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1. Multimodel Forecasting of Precipitation at Subseasonal Timescales Over the Southwest Tropical Pacific

Author

Damien Specq, Lauriane Batté, Michel Déqué, and Constantin Ardilouze

Subjects
Astronomy, QB1-991, Geology, QE1-996.5
Abstract

Abstract Multimodel ensemble (MME) reforecasts of rainfall at subseasonal time scales in the southwest tropical Pacific are constructed using six models (BoM, CMA, ECCC, ECMWF, Météo‐France, and UKMO) from the Subseasonal‐to‐Seasonal (S2S) database by member pooling. These reforecasts are verified at each grid point of the 110°E to 200°E; 30°S to 0° domain for the 1996–2013 DJF period. The evaluation is based on correlation and on the ROC skill score of the upper quintile of precipitation for both weekly targets and Weeks 3–4 outlook. Confirming previous results at the seasonal time scales, the MME reaches the highest skill and also improves the reliability of probabilistic forecasts. However, an equivalent ensemble size comparison between the MME and the individual models shows that the better performance of the MME compared to the best individual models is significantly related to the larger ensemble size of the MME. Forecast skill is then explained in light of potential sources of predictability by evaluating the performance of the models depending on the initial ENSO and MJO state. While the role of ENSO on predictability is quite consistent with its related rainfall anomalies, the role of the MJO is more ambiguous and strongly depends on the location: An initialization in active MJO conditions does not necessarily imply better forecasts. This influence of ENSO and the MJO on predictability does not change when switching from individual models to the MME.

Published
2020
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2. Empirical Run‐Time Bias Correction for Antarctic Regional Climate Projections With a Stretched‐Grid AGCM

Author

Gerhard Krinner, Julien Beaumet, Vincent Favier, Michel Déqué, and Claire Brutel‐Vuilmet

Subjects
bias correction, climate modeling, regional climate, Physical geography, GB3-5030, Oceanography, GC1-1581
Abstract

Abstract This work presents snapshot simulations of the late 20th and late 21st century Antarctic climate under the RCP8.5 scenario carried out with an empirically bias‐corrected global atmospheric general circulation model (AGCM), forced with bias‐corrected sea‐surface temperatures and sea ice and run with about 100‐km resolution over Antarctica. The bias correction substantially improves the simulated mean late 20th century climate. The simulated atmospheric circulation of the bias‐corrected model compares very favorably to the best available AMIP (Atmospheric Model Intercomparison Project)‐type climate models. The simulated interannual circulation variability is improved by the bias correction. Depending on the metric, a slight improvement or degradation is found in the simulated variability on synoptic timescales. The simulated climate change over the 21st century is broadly similar in the corrected and uncorrected versions of the atmospheric model, and atmospheric circulation patterns are not geographically “pinned” by the applied bias correction. These results suggest that the method presented here can be used for bias‐corrected climate projections. Finally, the authors discuss different possible choices in terms of the place of bias corrections and other intermediate steps in the modeling chain leading from global coupled climate simulations to impact assessment.

Published
2019
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3. A multi-model climate response over tropical Africa at +2 °C

Author

Michel Déqué, Sandro Calmanti, Ole Bøssing Christensen, Alessandro Dell Aquila, Cathrine Fox Maule, Andreas Haensler, Grigory Nikulin, and Claas Teichmann

Subjects
Climate change, Africa, Nile River, Niger River, Meteorology. Climatology, QC851-999, Social sciences (General), H1-99
Abstract

The impact of a +2 °C global warming on temperature and precipitation over tropical Africa is examined, based on an ensemble of 12 regional climate model scenario simulations. These 12 scenarios are re-phased so that they all correspond to the same global warming of 2 °C with respect to pre-industrial conditions. The continental temperature increase is above the global average. If heat waves are defined with the same temperature threshold in the reference climate and in the scenario, their frequency increases by a factor of 10. When the temperature threshold is adapted to future conditions, there is still a slight increase in frequency. The average precipitation does not show a significant response, due to model-to-model spread. However two compensating phenomena occur, which are robust among the models: (a) the number of rain days decreases whereas the precipitation intensity increases, and (b) the rain season occurs later during the year with less precipitation in early summer and more precipitation in late summer. Simulated daily temperature and precipitation data are combined in two impact models, one for the hydrology of the Nile and Niger basins, one for the food security of the different countries. They show that the main feature of the climate change is not a continuous trend signal, but an alternation of dry and wet decadal to multidecadal episodes.

Published
2017
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4. A fully coupled Mediterranean regional climate system model: design and evaluation of the ocean component for the 1980–2012 period

Author

Florence Sevault, Samuel Somot, Antoinette Alias, Clotilde Dubois, Cindy Lebeaupin-Brossier, Pierre Nabat, Fanny Adloff, Michel Déqué, and Bertrand Decharme

Subjects
Mediterranean Sea, regional climate system model, air-sea fluxes, hindcast simulation, interannual variability, Oceanography, GC1-1581, Meteorology. Climatology, QC851-999
Abstract

A fully coupled regional climate system model (CNRM-RCSM4) dedicated to the Mediterranean region is described and evaluated using a multidecadal hindcast simulation (1980–2012) driven by global atmosphere and ocean reanalysis. CNRM-RCSM4 includes the regional representation of the atmosphere (ALADIN-Climate model), land surface (ISBA model), rivers (TRIP model) and the ocean (NEMOMED8 model), with a daily coupling by the OASIS coupler. This model aims to reproduce the regional climate system with as few constraints as possible: there is no surface salinity, temperature relaxation, or flux correction; the Black Sea budget is parameterised and river runoffs (except for the Nile) are fully coupled. The atmospheric component of CNRM-RCSM4 is evaluated in a companion paper; here, we focus on the air–sea fluxes, river discharges, surface ocean characteristics, deep water formation phenomena and the Mediterranean thermohaline circulation. Long-term stability, mean seasonal cycle, interannual variability and decadal trends are evaluated using basin-scale climatologies and in-situ measurements when available. We demonstrate that the simulation shows overall good behaviour in agreement with state-of-the-art Mediterranean RCSMs. An overestimation of the shortwave radiation and latent heat loss as well as a cold Sea Surface Temperature (SST) bias and a slight trend in the bottom layers are the primary current deficiencies. Further, CNRM-RCSM4 shows high skill in reproducing the interannual to decadal variability for air–sea fluxes, river runoffs, sea surface temperature and salinity as well as open-sea deep convection, including a realistic simulation of the Eastern Mediterranean Transient. We conclude that CNRM-RCSM4 is a mature modelling tool allowing the climate variability of the Mediterranean regional climate system to be studied and understood. It is used in hindcast and scenario modes in the HyMeX and Med-CORDEX programs.

Published
2014
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5. The importance of using a high-resolution model to study the climate change on small islands: the Lesser Antilles case

Author

Philippe Cantet, Michel Déqué, Philippe Palany, and Jean-Louis Maridet

Subjects
climate change, regional climate model, RCP scenarios, Lesser Antilles, temperature, precipitation, Oceanography, GC1-1581, Meteorology. Climatology, QC851-999
Abstract

High-resolution climate change simulations over the Lesser Antilles are performed using the ALADIN-Climate regional climate model nested within the global model ARPEGE (Météo-France). Three sets of simulations are conducted at 10 km grid spacing for reference (1971–2000) and future climate (2071–2100) under two CMIP5 scenarios (RCP4.5 and RCP8.5). With the dynamical downscaling, islands of Lesser Antilles are considered as land by the model, whereas, for the driving model, there is only sea over the domain. Temperature and precipitation change are analysed on land and on sea separately. For temperature, the warming is greater on land than on sea, especially for the minimum daily temperature (3.2°C vs. 2.3°C for the RCP85 scenario). For precipitation, projections are less reliable because the seasonality is not well reproduced by the model. Nevertheless, simulations exhibit the fact that projections on land differ from one island to the other and disagree with those on sea notably during the wet season. This underlines the importance of the dynamical downscaling to study the climate on small islands. Statistical downscaling has been performed on the Guadeloupe Island to study changes in extreme precipitation indices. The projections provided by the regional climate model suggest an increase in extreme rainfall events: longer dry periods, a bigger annual total precipitation, more frequent very heavy daily precipitation and a stronger 1 d maximum precipitation, whereas for the driving Global Climate Model, these trends are less intense.

Published
2014
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6. Regional climate simulation with a mosaic of RCMs

Author

Michel Déqué

Subjects
Meteorology. Climatology, QC851-999
Abstract

The aim of the present study is to explore the possibility of getting high horizontal resolution over Europe by using a cluster of low computational cost atmospheric general circulation models (AGCM). The approach is based on global models with stretched grid, driven by a medium-resolution model serving as a "conductor" to maintain time consistency of the synoptic events and avoid climate degradation in the low resolution part of the grids. Thus the global models behave as regional climate models (RCM). A perfect model approach is used with a high resolution AGCM serving as a reference. The results show that when the different models are merged on a high resolution grid, the mean climate is similar to what is obtained with an equivalent high resolution AGCM with an unstretched grid. A climate change numerical experiment shows that this is also valid for the climate response to increased greenhouse gas concentration.

Published
2010
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7. CECILIA Regional Climate Simulations for Future Climate: Analysis of Climate Change Signal

Author

Michal Belda, Petr Skalák, Aleš Farda, Tomáš Halenka, Michel Déqué, Gabriella Csima, Judit Bartholy, Csaba Torma, Constanta Boroneant, Mihaela Caian, and Valery Spiridonov

Subjects
Meteorology. Climatology, QC851-999
Abstract

Regional climate models (RCMs) are important tools used for downscaling climate simulations from global scale models. In project CECILIA, two RCMs were used to provide climate change information for regions of Central and Eastern Europe. Models RegCM and ALADIN-Climate were employed in downscaling global simulations from ECHAM5 and ARPEGE-CLIMAT under IPCC A1B emission scenario in periods 2021–2050 and 2071–2100. Climate change signal present in these simulations is consistent with respective driving data, showing similar large-scale features: warming between 0 and 3°C in the first period and 2 and 5°C in the second period with the least warming in northwestern part of the domain increasing in the southeastern direction and small precipitation changes within range of +1 to −1 mm/day. Regional features are amplified by the RCMs, more so in case of the ALADIN family of models.

Published
2015
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8. Climate change impacts on the power generation potential of a European mid-century wind farms scenario

Author

Isabelle Tobin, Sonia Jerez, Robert Vautard, Françoise Thais, Erik van Meijgaard, Andreas Prein, Michel Déqué, Sven Kotlarski, Cathrine Fox Maule, Grigory Nikulin, Thomas Noël, and Claas Teichmann

Subjects
climate change impacts, wind energy, regional climate modelling, Europe, Environmental technology. Sanitary engineering, TD1-1066, Environmental sciences, GE1-350, Science, Physics, QC1-999
Abstract

Wind energy resource is subject to changes in climate. To investigate the impacts of climate change on future European wind power generation potential, we analyze a multi-model ensemble of the most recent EURO-CORDEX regional climate simulations at the 12 km grid resolution. We developed a mid-century wind power plant scenario to focus the impact assessment on relevant locations for future wind power industry. We found that, under two greenhouse gas concentration scenarios, changes in the annual energy yield of the future European wind farms fleet as a whole will remain within ±5% across the 21st century. At country to local scales, wind farm yields will undergo changes up to 15% in magnitude, according to the large majority of models, but smaller than 5% in magnitude for most regions and models. The southern fleets such as the Iberian and Italian fleets are likely to be the most affected. With regard to variability, changes are essentially small or poorly significant from subdaily to interannual time scales.

Published
2016
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9. Significant additional Antarctic warming in atmospheric bias-corrected ARPEGE projections

Author

Gerhard Krinner, Cécile Agosta, Michel Déqué, Julien Beaumet, Antoinette Alias, and Vincent Favier

Subjects
geography, geography.geographical_feature_category, Atmospheric circulation, Climatology, Environmental science, Antarctic ice sheet, Westerlies, Precipitation, Atmospheric model, Ice sheet, Southern Hemisphere, Latitude
Abstract

In this study, we use run-time bias-correction to correct for ARPEGE atmospheric model systematic errors on large-scale atmospheric circulation. The bias correction terms are built using the climatological mean of the adjustment terms on tendency errors in an ARPEGE simulation relaxed towards ERA-Interim reanalyses. The improvements with respect to the AMIP-style uncorrected control run for the general atmospheric circulation in the Southern Hemisphere are significant for mean state and daily variability. Comparisons for the Antarctic Ice Sheet with the polar-oriented regional atmospheric models MAR and RACMO2 and in-situ observations also suggest substantial bias reduction for near-surface temperature and precipitation in coastal areas. Applying the method to climate projections for the late 21st century (2071–2100) leads to large differences in the projected changes of the atmospheric circulation in the Southern high latitudes and of the Antarctic surface climate. The projected poleward shift and strengthening of the southern westerly winds are greatly reduced. These changes result in a significant 0.7 to 0.9 K additional warming and a 6 to 9 % additional increase in precipitation over the grounded ice sheet. The sensitivity of precipitation increase to temperature (+7.7 and +9 %.K−1) found is also higher than previous estimates. Highest additional warming rates are found over East Antarctica in summer. In winter, there is a dipole of weaker warming and weaker precipitation increase over West Antarctica, contrasted by a stronger warming and a concomitant stronger precipitation increase from Victoria to Adélie Land, associated with a weaker intensification of the Amundsen Sea Low.

Published
2020

10. Multi-component ensembles of future meteorological and natural snow conditions for 1500 m altitude in the Chartreuse mountain range, Northern French Alps

Author

Michel Déqué, Samuel Morin, Deborah Verfaillie, Nicolas Eckert, Yves Lejeune, Matthieu Lafaysse, Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Erosion torrentielle neige et avalanches (UR ETGR (ETNA)), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, 0208 environmental biotechnology, 02 engineering and technology, 01 natural sciences, Altitude, Natural hazard, lcsh:Environmental sciences, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, lcsh:GE1-350, geography, geography.geographical_feature_category, Global temperature, lcsh:QE1-996.5, 15. Life on land, Snowpack, Snow, CHARTREUSE MASSIF, 020801 environmental engineering, Water resources, lcsh:Geology, 13. Climate action, [SDU]Sciences of the Universe [physics], Climatology, [SDE]Environmental Sciences, Environmental science, Climate model, Mountain range
Abstract

This article investigates the climatic response of a series of indicators for characterizing annual snow conditions and corresponding meteorological drivers at 1500 m altitude in the Chartreuse mountain range in the Northern French Alps. Past and future changes were computed based on reanalysis and observations from 1958 to 2016, and using CMIP5–EURO-CORDEX GCM–RCM pairs spanning historical (1950–2005) and RCP2.6 (4), RCP4.5 and RCP8.5 (13 each) future scenarios (2006–2100). The adjusted climate model runs were used to drive the multiphysics ensemble configuration of the detailed snowpack model Crocus. Uncertainty arising from physical modeling of snow accounts for 20 % typically, although the multiphysics is likely to have a much smaller impact on trends. Ensembles of climate projections are rather similar until the middle of the 21st century, and all show a continuation of the ongoing reduction in average snow conditions, and sustained interannual variability. The impact of the RCPs becomes significant for the second half of the 21st century, with overall stable conditions with RCP2.6, and continued degradation of snow conditions for RCP4.5 and 8.5, the latter leading to more frequent ephemeral snow conditions. Changes in local meteorological and snow conditions show significant correlation with global temperature changes. Global temperature levels 1.5 and 2 ∘C above preindustrial levels correspond to a 25 and 32 % reduction, respectively, of winter mean snow depth with respect to the reference period 1986–2005. Larger reduction rates are expected for global temperature levels exceeding 2 ∘C. The method can address other geographical areas and sectorial indicators, in the field of water resources, mountain tourism or natural hazards.

Published
2018
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11. Assessing bias corrections of oceanic surface conditions for atmospheric models

Author

Rein Haarsma, Julien Beaumet, Gerhard Krinner, Michel Déqué, Laurent Li, Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Royal Netherlands Meteorological Institute (KNMI), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 010504 meteorology & atmospheric sciences, Atmospheric models, Anomaly (natural sciences), lcsh:QE1-996.5, 0207 environmental engineering, Boundary (topology), 02 engineering and technology, Function (mathematics), [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology, Atmospheric sciences, 01 natural sciences, lcsh:Geology, Constraint (information theory), Sea surface temperature, 13. Climate action, Consistency (statistics), Environmental science, 020701 environmental engineering, 0105 earth and related environmental sciences, Downscaling
Abstract

Future sea surface temperature and sea-ice concentration from coupled ocean–atmosphere general circulation models such as those from the CMIP5 experiment are often used as boundary forcings for the downscaling of future climate experiments. Yet, these models show some considerable biases when compared to the observations over present climate. In this paper, existing methods such as an absolute anomaly method and a quantile–quantile method for sea surface temperature (SST) as well as a look-up table and a relative anomaly method for sea-ice concentration (SIC) are presented. For SIC, we also propose a new analogue method. Each method is objectively evaluated with a perfect model test using CMIP5 model experiments and some real-case applications using observations. We find that with respect to other previously existing methods, the analogue method is a substantial improvement for the bias correction of future SIC. Consistency between the constructed SST and SIC fields is an important constraint to consider, as is consistency between the prescribed sea-ice concentration and thickness; we show that the latter can be ensured by using a simple parameterisation of sea-ice thickness as a function of instantaneous and annual minimum SIC.

Published
2019
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12. On the Link between Summer Dry Bias over the U.S. Great Plains and Seasonal Temperature Prediction Skill in a Dynamical Forecast System

Author

Constantin Ardilouze, Michel Déqué, Bertrand Decharme, Lauriane Batté, Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Moisture, 0207 environmental engineering, Forecast skill, 02 engineering and technology, [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology, 01 natural sciences, 13. Climate action, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Climatology, Seasonal forecasting, Environmental science, Predictability, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, 020701 environmental engineering, Water content, 0105 earth and related environmental sciences
Abstract

Soil moisture anomalies are expected to be a driver of summer predictability for the U.S. Great Plains since this region is prone to intense and year-to-year varying water and energy exchange between the land and the atmosphere. However, dynamical seasonal forecast systems struggle to deliver skillful summer temperature forecasts over that region, otherwise subject to a consistent warm-season dry bias in many climate models. This study proposes two techniques to mitigate the impact of this precipitation deficit on the modeled soil water content in a forecast system based on the CNRM-CM6-1 model. Both techniques lead to increased evapotranspiration during summer and reduced temperature and precipitation bias. However, only the technique based on a correction of the precipitation feeding the land surface throughout the forecast integration enables skillful summer prediction. Although this result cannot be generalized for other parts of the globe, it confirms the link between bias and skill over the U.S. Great Plains and pleads for continued efforts of the modeling community to tackle the summer bias affecting that region.

Published
2019
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13. Investigating the impact of soil moisture on European summer climate in ensemble numerical experiments

Author

Bart van den Hurk, Erik van Meijgaard, Michel Déqué, Constantin Ardilouze, Lauriane Batté, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and Royal Netherlands Meteorological Institute (KNMI)

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Ensemble forecasting, Climate change, 010502 geochemistry & geophysics, 01 natural sciences, 13. Climate action, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Climatology, Evapotranspiration, Soil water, Summer climate variability, Environmental science, Climate model, Precipitation, Soil moisture, Predictability, Regional Climate modelling, Ensembles, Water content, Land-atmosphere coupling, 0105 earth and related environmental sciences
Abstract

International audience; A better anticipation of high-impact heat and drought on human activity is the underlying motivation of many climate studies focused on the summer season. Although a large body of research has already highlighted the prominent impact of soil moisture anomalies on summer mid-latitudes climate variability and predictability, it still leaves room for a wide range of uncertainty and sometimes contradictions. The present work aims at revisiting soil moisture sensitivity studies by comparing an idealized ensemble model experiment in which soil moisture conditions are prescribed with a reference experiment in which soil moisture evolves freely. Two regional climate models centered over Europe contribute to these experiments and generate very similar results. Simulations with constrained soil moisture display significantly increased correlation between observed and simulated seasonal anomalies of maximum temperature, precipitation and surface solar radiation, as compared to the reference experiment. This widespread increase is not restricted to regions already known as hot-spots of land-atmosphere coupling such as southern Europe, where evapotranspiration is mainly driven by soil moisture. In spite of a limited change in the ensemble spread, the sensitivity experiments show a substantially modified magnitude of temperature and precipitation variability. A focus on two case studies reveal contrasting results for the 2003 and 2010 heat waves. These results stress the prominent role of soil moisture as a boundary condition of the climate system in Europe, including regions that have not been highlighted by previous sensitivity works.

Published
2019
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14. Empirical Run-Time Bias Correction for Antarctic Regional Climate Projections With a Stretched-Grid AGCM

Author

Michel Déqué, Claire Brutel-Vuilmet, Gerhard Krinner, Julien Beaumet, Vincent Favier, Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Recherche pour le Développement (IRD)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), and Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Global and Planetary Change, 010504 meteorology & atmospheric sciences, regional climate, 0207 environmental engineering, 02 engineering and technology, Grid, bias correction, 01 natural sciences, lcsh:Oceanography, 13. Climate action, Climatology, General Earth and Planetary Sciences, Environmental Chemistry, Environmental science, Climate model, Bias correction, lcsh:GC1-1581, lcsh:GB3-5030, 020701 environmental engineering, lcsh:Physical geography, climate modeling, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

This work presents snapshot simulations of the late 20th and late 21st century Antarctic climate under the RCP8.5 scenario carried out with an empirically bias‐corrected global atmospheric general circulation model (AGCM), forced with bias‐corrected sea‐surface temperatures and sea ice and run with about 100‐km resolution over Antarctica. The bias correction substantially improves the simulated mean late 20th century climate. The simulated atmospheric circulation of the bias‐corrected model compares very favorably to the best available AMIP (Atmospheric Model Intercomparison Project)‐type climate models. The simulated interannual circulation variability is improved by the bias correction. Depending on the metric, a slight improvement or degradation is found in the simulated variability on synoptic timescales. The simulated climate change over the 21st century is broadly similar in the corrected and uncorrected versions of the atmospheric model, and atmospheric circulation patterns are not geographically “pinned” by the applied bias correction. These results suggest that the method presented here can be used for bias‐corrected climate projections. Finally, the authors discuss different possible choices in terms of the place of bias corrections and other intermediate steps in the modeling chain leading from global coupled climate simulations to impact assessment.

Published
2019
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15. Predictability of soil moisture and river flows over France for the spring season

Author

Jean-Pierre Céron, Fabienne Regimbeau, Jean-Philippe Vidal, Florence Habets, S. Singla, Eric Martin, Michel Déqué, Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Structure et fonctionnement des systèmes hydriques continentaux (SISYPHE), Université Pierre et Marie Curie - Paris 6 (UPMC)-École pratique des hautes études (EPHE)-MINES ParisTech - École nationale supérieure des mines de Paris-Centre National de la Recherche Scientifique (CNRS), Hydrologie-Hydraulique (UR HHLY), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Université Pierre et Marie Curie - Paris 6 (UPMC)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-École Pratique des Hautes Études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Mines Paris - PSL (École nationale supérieure des mines de Paris)

Subjects
010504 meteorology & atmospheric sciences, DEBIT DE COURS D'EAU, 0207 environmental engineering, FRANCE, 02 engineering and technology, lcsh:Technology, 01 natural sciences, lcsh:TD1-1066, HYDROMETEOROLOGIE, Hydrology (agriculture), Streamflow, Hydrometeorology, Precipitation, Predictability, lcsh:Environmental technology. Sanitary engineering, 020701 environmental engineering, lcsh:Environmental sciences, 0105 earth and related environmental sciences, lcsh:GE1-350, lcsh:T, HUMIDITE DU SOL, lcsh:Geography. Anthropology. Recreation, Snow, PREVISION, lcsh:G, 13. Climate action, Climatology, Soil water, [SDE]Environmental Sciences, Environmental science, Climate model
Abstract

Sources of spring predictability of the hydrological system over France were studied on a seasonal time scale over the 1960–2005 period. Two random sampling experiments were set up in order to test the relative importance of the land surface initial state and the atmospheric forcing. The experiments were based on the SAFRAN-ISBA-MODCOU hydrometeorological suite which computed soil moisture and river flow forecasts over a 8-km grid and more than 880 river-gauging stations. Results showed that the predictability of hydrological variables primarily depended on the seasonal atmospheric forcing (mostly temperature and total precipitation) over most plains, whereas it mainly depended on snow cover over high mountains. However, the Seine catchment area was an exception as the skill mainly came from the initial state of its large and complex aquifers. Seasonal meteorological hindcasts with the Météo-France ARPEGE climate model were then used to force the ISBA-MODCOU hydrological model and obtain seasonal hydrological forecasts from 1960 to 2005 for the entire March-April-May period. Scores from this seasonal hydrological forecasting suite could thus be compared with the random atmospheric experiment. Soil moisture and river flow skill scores clearly showed the added value in seasonal meteorological forecasts in the north of France, contrary to the Mediterranean area where values worsened.

Published
2018
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16. The method ADAMONT v1.0 for statistical adjustment of climate projections applicable to energy balance land surface models

Author

Matthieu Lafaysse, Samuel Morin, Michel Déqué, and Deborah Verfaillie

Subjects
Meteorological reanalysis, 010504 meteorology & atmospheric sciences, Meteorology, lcsh:QE1-996.5, 0208 environmental biotechnology, Elevation, 02 engineering and technology, Grid, Snow, 01 natural sciences, Wind speed, 020801 environmental engineering, lcsh:Geology, Environmental science, Climate model, Precipitation, 0105 earth and related environmental sciences, Quantile
Abstract

We introduce the method ADAMONT v1.0 to adjust and disaggregate daily climate projections from a regional climate model against an observational dataset at hourly time resolution. The method uses a refined quantile mapping approach for statistical adjustment and an analogous method for sub-daily disaggregation. The method produces ultimately adjusted hourly time series of temperature, precipitation, wind speed, humidity, and short- and longwave radiation, which can in turn be used to force any energy balance land surface model. While the method is generic and can be employed on any appropriate observation time series, here we focus on the description and evaluation of the method in the French mountainous regions. The observational dataset used here is the SAFRAN meteorological reanalysis, which covers the entire French Alps split into 23 massifs, within which meteorological conditions are provided for several 300 m elevation bands. In order to evaluate the skills of the method itself, it is applied to the ALADIN-Climate v5 RCM using the ERA-Interim reanalysis as boundary conditions, for the time period from 1980 to 2010. Results of the ADAMONT method are compared to the SAFRAN reanalysis itself. Various evaluation criteria are used for temperature, precipitation, but also snow depth, which is computed by the SURFEX/ISBA-Crocus model using the meteorological driving data from either the adjusted RCM data, or the SAFRAN reanalysis itself. The evaluation addresses in particular the time transferability of the method (using various learning/application time periods), the impact of the RCM grid point selection procedure for each massif/altitude band configuration, and the inter-variable consistency of the adjusted meteorological data generated by the method. Results show that the performance of the method is satisfactory, with similar or even better evaluation metrics than alternative methods. However, results for air temperature are generally better than for precipitation. Results in terms of snow depth are satisfactory, which can be viewed as indicating a reasonably good inter-variable consistency of the meteorological data produced by the method. In terms of temporal transferability (evaluated over time periods of 15 years only), results depend on the learning period. In terms of RCM grid point selection technique, the use of a complex RCM grid points selection technique, taking into account horizontal but also altitudinal proximity to SAFRAN massif centre points/altitude couples, generally degrades evaluation metrics for high altitudes, compared to a simpler grid point selection method based on horizontal distance.

Published
2018

17. Benefits of explicit urban parameterization in regional climate modeling to study climate and city interactions

Author

V. Masson, Michel Déqué, Aude Lemonsu, Antoinette Alias, Samuel Somot, M. Daniel, Météo-France [Paris], Météo France, Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Météo-France, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Horizontal resolution, Atmospheric Science, 010504 meteorology & atmospheric sciences, Land use, [SDE.MCG]Environmental Sciences/Global Changes, Urban model, 010502 geochemistry & geophysics, 01 natural sciences, Atmosphere, 13. Climate action, Climatology, Urbanization, 11. Sustainability, [SDE]Environmental Sciences, Environmental science, Climate model, Precipitation, Urban heat island, 0105 earth and related environmental sciences
Abstract

International audience; Most climate models do not explicitly model urban areas and at best describe them as rock covers. Nonetheless, the very high resolutions reached now by the regional climate models may justify and require a more realistic parameterization of surface exchanges between urban canopy and atmosphere. To quantify the potential impact of urbanization on the regional climate, and evaluate the benefits of a detailed urban canopy model compared with a simpler approach, a sensitivity study was carried out over France at a 12-km horizontal resolution with the ALADIN-Climate regional model for 1980-2009 time period. Different descriptions of land use and urban modeling were compared, corresponding to an explicit modeling of cities with the urban canopy model TEB, a conventional and simpler approach representing urban areas as rocks, and a vegetated experiment for which cities are replaced by natural covers. A general evaluation of ALADIN-Climate was first done, that showed an overestimation of the incoming solar radiation but satisfying results in terms of precipitation and near-surface temperatures. The sensitivity analysis then highlighted that urban areas had a significant impact on modeled near-surface temperature. A further analysis on a few large French cities indicated that over the 30 years of simulation they all induced a warming effect both at daytime and nighttime with values up to + 1.5 °C for the city of Paris. The urban model also led to a regional warming extending beyond the urban areas boundaries. Finally, the comparison to temperature observations available for Paris area highlighted that the detailed urban canopy model improved the modeling of the urban heat island compared with a simpler approach.

Published
2018
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18. Evaluation of simulated decadal variations over the Euro-Mediterranean region from ENSEMBLES to Med-CORDEX

Author

Leone Cavicchia, Michel Déqué, Vladimir Djurdjevic, Sandro Calmanti, Alessandro Dell'Aquila, Annarita Mariotti, Miguel Ángel Gaertner, Silvio Gualdi, Sophie Bastin, Marta Domínguez, Agenzia Nazionale per le nuove Tecnologie, l’energia e lo sviluppo economico sostenibile = Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), NOAA Climate Program Office (CPO), National Oceanic and Atmospheric Administration (NOAA), SPACE - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centro Euro-Mediterraneo per i Cambiamenti Climatici [Bologna] (CMCC), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), University of Belgrade [Belgrade], Instituto de Ciencias Ambientales [Toledo] (ICAM), Universidad de Castilla-La Mancha = University of Castilla-La Mancha (UCLM), European Union, European Project: 282746,EC:FP7:ENV,FP7-ENV-2011,IMPACT2C(2011), European Project: 308378,EC:FP7:ENV,FP7-ENV-2012-two-stage,SPECS(2012), Agenzia Nazionale per le nuove Tecnologie, l’energia e lo sviluppo economico sostenibile (ENEA), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Météo France-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Universidad de Castilla-La Mancha (UCLM)

Subjects
Mediterranean climate, Euro-Mediterranean region, Atmospheric Science, Previous generation, 010504 meteorology & atmospheric sciences, 0208 environmental biotechnology, Climate change, Stratification (water), 02 engineering and technology, Regional climate modeling, 01 natural sciences, 020801 environmental engineering, Summer season, Amplitude, Evaluation metrics, 13. Climate action, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Climatology, Spatial ecology, Environmental science, Long term variations, Model development, 0105 earth and related environmental sciences
Abstract

International audience; Med-CORDEX simulations over the period 1979–2011 are evaluated with regard to their capability to represent observed decadal variations over the Euro-Mediterranean region and improve upon previous generation simulations from the ENSEMBLES project in their various experimental set-ups. Such an evaluation is needed to inform the use of these simulations and also future model development. For temperature, both Med-CORDEX and ENSEMBLES simulations tend to provide comparable results: they generally capture the sign and timing of the anomalies but not the amplitude. In general, no clear stratification appears when considering different types of Med-CORDEX regional modeling systems. Rather, it is remarkable that certain periods are poorly represented by all systems with a general underestimation of the observed long-term temperature trend, mostly in the summer season, even with respect to the corresponding global drivers. For precipitation, the Med-CORDEX simulations are closer to observations than the other datasets, with some improvement with respect to ENSEMBLES dataset. In general, all the systems experience difficulties in representing anomalies during specific periods or for specific regions. These appear in part due to limitations in the reanalysis boundary forcing data. For instance, in the second part of 1980s, the spatial patterns of surface air temperature during DJF/MAM are generally poorly represented, as well as the regionally averaged MAM/JJA surface air temperature decadal anomalies. Overall, the evaluation suggests limited improvement in Med-CORDEX simulations compared to ENSEMBLES, and a lack of sensitivity to resolution or coupling configuration, with persisting problems in part likely related to the representation of surface processes that could also affect the viability of future projections (e.g. the estimation of temperature trends). A set of decadal variability evaluation metrics, as applied in this study, could be useful in the context of a broader evaluation framework.

Published
2018
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19. A multi-model climate response over tropical Africa at +2 °C

Author

Alessandro Dell Aquila, Cathrine Fox Maule, Michel Déqué, Grigory Nikulin, Ole Bøssing Christensen, Sandro Calmanti, Claas Teichmann, and Andreas Haensler

Subjects
Wet season, Atmospheric Science, 010504 meteorology & atmospheric sciences, Niger River, 0208 environmental biotechnology, Climate change, 02 engineering and technology, lcsh:QC851-999, 01 natural sciences, Hydrology (agriculture), Precipitation, lcsh:Social sciences (General), 0105 earth and related environmental sciences, Global and Planetary Change, Global warming, 020801 environmental engineering, Geography, 13. Climate action, Climatology, Africa, Nile River, lcsh:Meteorology. Climatology, lcsh:H1-99, Climate model, Climate response, Intensity (heat transfer)
Abstract

The impact of a +2 °C global warming on temperature and precipitation over tropical Africa is examined, based on an ensemble of 12 regional climate model scenario simulations. These 12 scenarios are re-phased so that they all correspond to the same global warming of 2 °C with respect to pre-industrial conditions. The continental temperature increase is above the global average. If heat waves are defined with the same temperature threshold in the reference climate and in the scenario, their frequency increases by a factor of 10. When the temperature threshold is adapted to future conditions, there is still a slight increase in frequency. The average precipitation does not show a significant response, due to model-to-model spread. However two compensating phenomena occur, which are robust among the models: (a) the number of rain days decreases whereas the precipitation intensity increases, and (b) the rain season occurs later during the year with less precipitation in early summer and more precipitation in late summer. Simulated daily temperature and precipitation data are combined in two impact models, one for the hydrology of the Nile and Niger basins, one for the food security of the different countries. They show that the main feature of the climate change is not a continuous trend signal, but an alternation of dry and wet decadal to multidecadal episodes.

Published
2017
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20. The subseasonal to seasonal (S2S) prediction project database

Author

M. Manoussakis, Hai Lin, I. Mallas, C. Codorean, Arun Kumar, Andrew W. Robertson, Frederic Vitart, L. Zhang, E. Fucile, A. Minami, M. Chen, Yuhei Takaya, Piero Malguzzi, Constantin Ardilouze, J. Hodgson, Mikhail A. Tolstykh, H.-S. Kang, A. Bonet, Anca Brookshaw, D.-J. Won, Tetsuo Nakazawa, Paolo Ruti, Manuel Fuentes, S. Najm, Michel Déqué, Xiangwen Liu, D. Mastrangelo, Michel Rixen, Harry H. Hendon, C. Sun, Craig MacLachlan, Y. Nie, R. Mladek, H. Xiao, Peter McLean, Laura Ferranti, Tongwen Wu, Steven J. Woolnough, Guoqiang Liu, F. Venuti, R. B. Zaripov, and Duane E. Waliser

Subjects
IMPACTS, Atmospheric Science, WEATHER FORECASTS, 010504 meteorology & atmospheric sciences, Meteorology, Database, 0208 environmental biotechnology, Forecast skill, 02 engineering and technology, computer.software_genre, 01 natural sciences, 020801 environmental engineering, Deliverable, Systems research, Climatology, Research community, Environmental science, Predictability, Time range, computer, 0105 earth and related environmental sciences
Abstract

Demands are growing rapidly in the operational prediction and applications communities for forecasts that fill the gap between medium-range weather and long-range or seasonal forecasts. Based on the potential for improved forecast skill at the subseasonal to seasonal time range, the Subseasonal to Seasonal (S2S) Prediction research project has been established by the World Weather Research Programme/World Climate Research Programme. A main deliverable of this project is the establishment of an extensive database containing subseasonal (up to 60 days) forecasts, 3 weeks behind real time, and reforecasts from 11 operational centers, modeled in part on the The Observing System Research and Predictability Experiment (THORPEX) Interactive Grand Global Ensemble (TIGGE) database for medium-range forecasts (up to 15 days). The S2S database, available to the research community since May 2015, represents an important tool to advance our understanding of the subseasonal to seasonal time range that has been considered for a long time as a “desert of predictability.” In particular, this database will help identify common successes and shortcomings in the model simulation and prediction of sources of subseasonal to seasonal predictability. For instance, a preliminary study suggests that the S2S models significantly underestimate the amplitude of the Madden–Julian oscillation (MJO) teleconnections over the Euro-Atlantic sector. The S2S database also represents an important tool for case studies of extreme events. For instance, a multimodel combination of S2S models displays higher probability of a landfall over the islands of Vanuatu 2–3 weeks before Tropical Cyclone Pam devastated the islands in March 2015.

Published
2017
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21. How realistic are air quality hindcasts driven by forcings from climate model simulations?

Author

Muriel Joly, Béatrice Josse, Laura Watson, Joaquim Arteta, Virginie Marécal, Michel Déqué, D. Saint Martin, Vincent-Henri Peuch, and Gwendoline Lacressonnière

Subjects
lcsh:Geology, Boundary layer, Deposition (aerosol physics), Mean squared error, Climatology, lcsh:QE1-996.5, Range (statistics), Humidity, Environmental science, Climate model, Context (language use), Atmospheric sciences, Air quality index
Abstract

Predicting how European air quality could evolve over the next decades in the context of changing climate requires the use of climate models to produce results that can be averaged in a climatologically and statistically sound manner. This is a very different approach from the one that is generally used for air quality hindcasts for the present period; analysed meteorological fields are used to represent specifically each date and hour. Differences arise both from the fact that a climate model run results in a pure model output, with no influence from observations (which are useful to correct for a range of errors), and that in a "climate" set-up, simulations on a given day, month or even season cannot be related to any specific period of time (but can just be interpreted in a climatological sense). Hence, although an air quality model can be thoroughly validated in a "realistic" set-up using analysed meteorological fields, the question remains of how far its outputs can be interpreted in a "climate" set-up. For this purpose, we focus on Europe and on the current decade using three 5-yr simulations performed with the multiscale chemistry-transport model MOCAGE and use meteorological forcings either from operational meteorological analyses or from climate simulations. We investigate how statistical skill indicators compare in the different simulations, discriminating also the effects of meteorology on atmospheric fields (winds, temperature, humidity, pressure, etc.) and on the dependent emissions and deposition processes (volatile organic compound emissions, deposition velocities, etc.). Our results show in particular how differing boundary layer heights and deposition velocities affect horizontal and vertical distributions of species. When the model is driven by operational analyses, the simulation accurately reproduces the observed values of O3, NOx, SO2 and, with some bias that can be explained by the set-up, PM10. We study how the simulations driven by climate forcings differ, both due to the realism of the forcings (lack of data assimilated and lower resolution) and due to the lack of representation of the actual chronology of events. We conclude that the indicators such as mean bias, mean normalized bias, RMSE and deviation standards can be used to interpret the results with some confidence as well as the health-related indicators such as the number of days of exceedance of regulatory thresholds. These metrics are thus considered to be suitable for the interpretation of simulations of the future evolution of European air quality.

Published
2012

22. Impacts of future climatic change (2070–2099) on the potential occurrence of debris flows: a case study in the Massif des Ecrins (French Alps)

Author

Daniel Brunstein, Mathieu Vrac, Vincent Jomelli, Delphine Grancher, Michel Déqué, Laboratoire de géographie physique : Environnements Quaternaires et Actuels (LGP), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Hydrology, Atmospheric Science, Global and Planetary Change, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Elevation, Climate change, Current period, Massif, 010502 geochemistry & geophysics, Spatial distribution, 01 natural sciences, Debris, [SDE.ES]Environmental Sciences/Environmental and Society, 13. Climate action, Trend surface analysis, [SDE]Environmental Sciences, Environmental science, Physical geography, Scale (map), ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

In this paper we investigate the impacts of future climatic change on the occurrence of debris flows in the Massif des Ecrins (French Alps). Two distinct aspects are discussed: the impact of future climatic change on the evolution of the process, and changes in the spatial distribution. Three climate simulations are presented for the current period (1970-1999) and for future periods (2070-2099) using GCM ARPEGE CLIMAT model developed by M,t,o-France. Simulated data are then statistically downscaled to obtain a higher spatial resolution. In the first step, we compare occurrence probabilities in the current period and in the next century. In the second step, we estimate which zones would be affected by the process in the future at the scale of the Massif des Ecrins. For the current period, the best model was obtained between debris flows and the number of days between June 15th and October 15th with more than 20 mm calculated either from observed meteorological or simulated data. Results of the ARPEGE model considering the A2 hypothesis (IPCC 2007) showed that the most significant climatic trends for the end of the century will be a decrease in intense rainy events and an increase in temperature. These trends are expected to reduce the occurrence of hill slope debris flows in the Massif des Ecrins. From a spatial point of view, the increase in temperature should result in a shift of the 0A degrees C isotherm to a higher elevation which, in turn, should result in a 20% reduction of the number of slopes affected by the process.

Published
2009
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23. Climate change impacts on the power generation potential of a European mid-century wind farms scenario

Author

Andreas F. Prein, Claas Teichmann, Cathrine Fox Maule, Robert Vautard, Michel Déqué, Erik van Meijgaard, Isabelle Tobin, Thomas Noël, Françoise Thais, Sven Kotlarski, Sonia Jerez, Grigory Nikulin, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Universidad de Murcia, Extrèmes : Statistiques, Impacts et Régionalisation (ESTIMR), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut Technico-Economie (TECH ECO (ex-ITESE)), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Royal Netherlands Meteorological Institute (KNMI), National Center for Atmospheric Research [Boulder] (NCAR), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Danish Meteorological Institute (DMI), Swedish Meteorological and Hydrological Institute (SMHI), Helmholtz-Zentrum Geesthacht (GKSS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Wind power, Resource (biology), Climate Research, Renewable Energy, Sustainability and the Environment, business.industry, Impact assessment, 020209 energy, [SPI.NRJ]Engineering Sciences [physics]/Electric power, Public Health, Environmental and Occupational Health, Magnitude (mathematics), Climate change, 02 engineering and technology, 7. Clean energy, Klimatforskning, Electricity generation, Performance ratio, 13. Climate action, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Climatology, Greenhouse gas, 0202 electrical engineering, electronic engineering, information engineering, Environmental science, business, Climate change impacts, Wind energy, Regional climate modelling, Europe, General Environmental Science
Abstract

Wind energy resource is subject to changes in climate. To investigate the impacts of climate change on future European wind power generation potential, we analyze a multi-model ensemble of the most recent EURO-CORDEX regional climate simulations at the 12 km grid resolution. We developed a mid-century wind power plant scenario to focus the impact assessment on relevant locations for future wind power industry. We found that, under two greenhouse gas concentration scenarios, changes in the annual energy yield of the future European wind farms fleet as a whole will remain within ±5% across the 21st century. At country to local scales, wind farm yields will undergo changes up to 15% in magnitude, according to the large majority of models, but smaller than 5% in magnitude for most regions and models. The southern fleets such as the Iberian and Italian fleets are likely to be the most affected. With regard to variability, changes are essentially small or poorly significant from subdaily to interannual time scales. ISSN:1748-9326 ISSN:1748-9318

Published
2016
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24. Randomly correcting model errors in the ARPEGE-Climate v6.1 component of CNRM-CM: applications for seasonal forecasts

Author

Lauriane Batté, Michel Déqué, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), European Project: 308378,EC:FP7:ENV,FP7-ENV-2012-two-stage,SPECS(2012), and Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Ensemble forecasting, Meteorology, 0208 environmental biotechnology, lcsh:QE1-996.5, Northern Hemisphere, Mode (statistics), Geopotential height, Perturbation (astronomy), 02 engineering and technology, Atmospheric model, [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology, 01 natural sciences, 020801 environmental engineering, lcsh:Geology, Variable (computer science), 13. Climate action, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, [SDU]Sciences of the Universe [physics], Climatology, Errors-in-variables models, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, Mathematics
Abstract

Stochastic methods are increasingly used in global coupled model climate forecasting systems to account for model uncertainties. In this paper, we describe in more detail the stochastic dynamics technique introduced by Batté and Déqué (2012) in the ARPEGE-Climate atmospheric model. We present new results with an updated version of CNRM-CM using ARPEGE-Climate v6.1, and show that the technique can be used both as a means of analyzing model error statistics and accounting for model inadequacies in a seasonal forecasting framework.The perturbations are designed as corrections of model drift errors estimated from a preliminary weakly nudged re-forecast run over an extended reference period of 34 boreal winter seasons. A detailed statistical analysis of these corrections is provided, and shows that they are mainly made of intra-month variance, thereby justifying their use as in-run perturbations of the model in seasonal forecasts. However, the interannual and systematic error correction terms cannot be neglected. Time correlation of the errors is limited, but some consistency is found between the errors of up to 3 consecutive days.These findings encourage us to test several settings of the random draws of perturbations in seasonal forecast mode. Perturbations are drawn randomly but consistently for all three prognostic variables perturbed. We explore the impact of using monthly mean perturbations throughout a given forecast month in a first ensemble re-forecast (SMM, for stochastic monthly means), and test the use of 5-day sequences of perturbations in a second ensemble re-forecast (S5D, for stochastic 5-day sequences). Both experiments are compared in the light of a REF reference ensemble with initial perturbations only. Results in terms of forecast quality are contrasted depending on the region and variable of interest, but very few areas exhibit a clear degradation of forecasting skill with the introduction of stochastic dynamics. We highlight some positive impacts of the method, mainly on Northern Hemisphere extra-tropics. The 500 hPa geopotential height bias is reduced, and improvements project onto the representation of North Atlantic weather regimes. A modest impact on ensemble spread is found over most regions, which suggests that this method could be complemented by other stochastic perturbation techniques in seasonal forecasting mode.

Published
2016
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25. A fully coupled Mediterranean regional climate system model: design and evaluation of the ocean component for the 1980-2012 period

Author

Fanny Adloff, Michel Déqué, Antoinette Alias, Pierre Nabat, Bertrand Decharme, Samuel Somot, Cindy Lebeaupin-Brossier, Clotilde Dubois, Florence Sevault, and SMHI

Subjects
Mediterranean climate, Atmospheric Science, air-sea fluxes, interannual variability, lcsh:QC851-999, regional climate system model, Oceanography, Ocean modelling, Mediterranean Sea, Regional Coupled System Model, Atmosphere, lcsh:Oceanography, Sea surface temperature, Mediterranean sea, Regional climate system modelling, hindcast simulation, 13. Climate action, Climatology, Latent heat, Environmental science, Hindcast, lcsh:Meteorology. Climatology, Thermohaline circulation, lcsh:GC1-1581, Shortwave radiation
Abstract

A fully coupled regional climate system model (CNRM-RCSM4) dedicated to the Mediterranean region is described and evaluated using a multidecadal hindcast simulation (1980–2012) driven by global atmosphere and ocean reanalysis. CNRM-RCSM4 includes the regional representation of the atmosphere (ALADIN-Climate model), land surface (ISBA model), rivers (TRIP model) and the ocean (NEMOMED8 model), with a daily coupling by the OASIS coupler. This model aims to reproduce the regional climate system with as few constraints as possible: there is no surface salinity, temperature relaxation, or flux correction; the Black Sea budget is parameterised and river runoffs (except for the Nile) are fully coupled. The atmospheric component of CNRM-RCSM4 is evaluated in a companion paper; here, we focus on the air–sea fluxes, river discharges, surface ocean characteristics, deep water formation phenomena and the Mediterranean thermohaline circulation. Long-term stability, mean seasonal cycle, interannual variability and decadal trends are evaluated using basin-scale climatologies and in-situ measurements when available. We demonstrate that the simulation shows overall good behaviour in agreement with state-of-the-art Mediterranean RCSMs. An overestimation of the shortwave radiation and latent heat loss as well as a cold Sea Surface Temperature (SST) bias and a slight trend in the bottom layers are the primary current deficiencies. Further, CNRM-RCSM4 shows high skill in reproducing the interannual to decadal variability for air–sea fluxes, river runoffs, sea surface temperature and salinity as well as open-sea deep convection, including a realistic simulation of the Eastern Mediterranean Transient. We conclude that CNRM-RCSM4 is a mature modelling tool allowing the climate variability of the Mediterranean regional climate system to be studied and understood. It is used in hindcast and scenario modes in the HyMeX and Med-CORDEX programs. Keywords: Mediterranean Sea, regional climate system model, air-sea fluxes, hindcast simulation, interannual variability (Published: 18 November 2014) Citation: Tellus A 2014, 66 , 23967, http://dx.doi.org/10.3402/tellusa.v66.23967

Published
2014

26. Debris flow activity related to recent climate conditions in the French Alps: A regional investigation

Author

Eric Martin, Irina Pavlova, Vincent Jomelli, Delphine Grancher, Daniel Brunstein, Michel Déqué, Laboratoire de géographie physique : Environnements Quaternaires et Actuels (LGP), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Composites Thermostructuraux (LCTS), Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Snecma-SAFRAN group-Centre National de la Recherche Scientifique (CNRS), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Paris 1 Panthéon-Sorbonne (UP1), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Climate change, Logistic regression, [SHS.GEO]Humanities and Social Sciences/Geography, 010502 geochemistry & geophysics, 01 natural sciences, Debris flow, Current (stream), Climate changes, Intensity/duration thresholds, 13. Climate action, Climatology, Period (geology), Precipitation, Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Earth-Surface Processes, Debris flow activity
Abstract

The primary objective of this study was to document the relationships between current climatic conditions and debris flow activity in the French Alps based on a large historical database of debris flow events covering 35 years up to the present. The French Alps are composed of two contrasting geographic areas so two debris flow regions with different activity patterns were defined. For the period 1970–2005, the database contains 565 debris flow events in 87 catchments in the northern part of the French Alps, and in 150 catchments in the southern part. Possible links between debris flow and climate were investigated using two different approaches. The first approach was determining the rainfall thresholds responsible for triggering debris flow events by analysing the links between the intensity and the duration of rainfall events. The second approach used a probabilistic logit model to explore the links between the triggering of debris flow events and temperature and precipitation during the active debris flow period to identify inter-annual variability. Reanalysis data were used to document climate conditions in the two study areas. According to the results, in 80% of all debris flow events, precipitation was recorded during the three days preceding the event. However, in most cases, the quantity of precipitation associated with triggering of the debris flow was very low. Total precipitation exceeded 10 mm in only 30% of all cases. We attribute this to the convective nature of summer precipitation, which is quite difficult to model. Probabilistic analysis of the debris flow inventory in the two regions revealed that different parameters were responsible for changes in annual debris-flow activity. In the northern part of the French Alps, the number of rainy days and the maximum daily temperature affected debris flow, while in the southern part the only significant factor was mean daily temperature during the period of debris flow activity (May–October). Model scores had an accuracy of 75% and 70% in the northern and southern Alps, respectively. Our observations revealed that the increase in the above parameters has influenced changes in debris flow activity in both regions, where the number of debris flow events has doubled over the last 35 years.

Published
2014
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27. European air quality in the 2030s and 2050s: Impacts of global and regional emission trends and of climate change

Author

Michel Déqué, Muriel Joly, Vincent-Henri Peuch, David Saint-Martin, Béatrice Josse, Virginie Marécal, Gwendoline Lacressonnière, Robert Vautard, Joaquim Arteta, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Extrèmes : Statistiques, Impacts et Régionalisation (ESTIMR), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Pollution, Pollutant, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Atmospheric Science, Ozone, media_common.quotation_subject, Northern Hemisphere, Climate change, 7. Clean energy, chemistry.chemical_compound, Surface ozone, chemistry, 13. Climate action, Climatology, Environmental science, Tropospheric ozone, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Air quality index, ComputingMilieux_MISCELLANEOUS, General Environmental Science, media_common
Abstract

A chemistry-transport model using two-way nested regional (Europe) and global domains is used to evaluate the effects of climate and emission changes on air quality over Europe for the 2030s and 2050s, by comparison with the emissions and climate of the recent past. We investigated the pollutant levels under the implementations of reduced anthropogenic emissions (NO x , SO 2 , etc) over Europe and, at the global scale, under the Representative Concentrations Pathways (RCP8.5) scenario produced by the Fifth Assessment Report (AR5) of IPCC. The simulations show an increase in surface ozone in northwestern Europe and a decrease in southern areas in the future horizons studied here. Over Europe, average O 3 levels steadily increase with a rate of around 3 μg m −3 per decade in summer. For this pollutant, the contributions of long range transport over the Northern Hemisphere and climate changes have been assessed and appear to counterbalance and even slightly outweigh the effects of European reductions in precursors' anthropogenic emissions. The tropospheric ozone budget is found to be dominated by enhanced stratosphere–troposphere exchanges in future climate while the chemical budget is significantly reduced. Our results show that a NO x -limited chemical regime will stretch over most of Europe, including especially Western France in the future. These findings allow supporting efficient future precursor emissions abatement strategies in order to limit O 3 pollution and maintain or improve air quality standards in Europe.

Published
2014
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28. Regional climate modeling on European scales : A joint standard evaluation of the EURO-CORDEX RCM ensemble

Author

Christoph Schär, Daniel Lüthi, Grigory Nikulin, Ole Bøssing Christensen, Kirsten Warrach-Sagi, Klaus Goergen, Michel Déqué, Sven Kotlarski, Andreas Gobiet, Volker Wulfmeyer, Daniela Jacob, Claas Teichmann, E. van Meijgaard, Augustin Colette, Robert Vautard, Klaus Keuler, Institute for Atmospheric and Climate Science [Zürich] (IAC), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Institut National de l'Environnement Industriel et des Risques (INERIS), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), University of Bonn, Climate Service Center [Hambourg] (GERICS), Helmholtz-Zentrum Geesthacht (GKSS), Royal Netherlands Meteorological Institute (KNMI), Swedish Meteorological and Hydrological Institute (SMHI), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), University of Hohenheim, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Universität Bonn = University of Bonn, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Extrèmes : Statistiques, Impacts et Régionalisation (ESTIMR), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Brandenburg University of Technology [Cottbus – Senftenberg] (BTU), Danish Climate Centre, Danish Meteorological Institute (DMI), and Civs, Gestionnaire

Subjects
[SDE] Environmental Sciences, 010504 meteorology & atmospheric sciences, lcsh:QE1-996.5, 0207 environmental engineering, Magnitude (mathematics), 02 engineering and technology, 01 natural sciences, 7. Clean energy, lcsh:Geology, Data set, 13. Climate action, Climatology, Air temperature, [SDE]Environmental Sciences, Range (statistics), Environmental science, Climate model, Precipitation, 020701 environmental engineering, Joint (geology), Downscaling, 0105 earth and related environmental sciences
Abstract

EURO-CORDEX is an international climate downscaling initiative that aims to provide high-resolution climate scenarios for Europe. Here an evaluation of the ERA-Interim-driven EURO-CORDEX regional climate model (RCM) ensemble is presented. The study documents the performance of the individual models in representing the basic spatio-temporal patterns of the European climate for the period 1989–2008. Model evaluation focuses on near-surface air temperature and precipitation, and uses the E-OBS dataset as observational reference. The ensemble consists of 17 simulations carried out by seven different models at grid resolutions of 12 km (nine experiments) and 50 km (eight experiments). Several performance metrics computed from monthly and seasonal mean values are used to assess model performance over eight sub-domains of the European continent. Results are compared to those for the ERA40-driven ENSEMBLES simulations. The analysis confirms the ability of RCMs to capture the basic features of the European climate, including its variability in space and time. But it also identifies non-negligible deficiencies of the simulations for selected metrics, regions and seasons. Seasonally and regionally averaged temperature biases are mostly smaller than 1.5 °C, while precipitation biases are typically located in the ±40% range. Some bias characteristics, such as a predominant cold and wet bias in most seasons and over most parts of Europe and a warm and dry summer bias over southern and south-eastern Europe reflect common model biases. For seasonal mean quantities averaged over large European sub-domains, no clear benefit of an increased spatial resolution (12 km vs. 50 km) can be identified. The bias ranges of the EURO-CORDEX ensemble mostly correspond to those of the ENSEMBLES simulations, but some improvements in model performance can be identified (e.g., a less pronounced southern European warm summer bias). The temperature bias spread across different configurations of one individual model can be of a similar magnitude as the spread across different models, demonstrating a strong influence of the specific choices in physical parameterizations and experimental setup on model performance. Based on a number of simply reproducible metrics, the present study quantifies the currently achievable accuracy of RCMs used for regional climate simulations over Europe and provides a quality standard for future model developments.

Published
2014
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29. EURO-CORDEX: new high-resolution climate change projections for European impact research

Author

Sven Kotlarski, Michel Déqué, Andreas Gobiet, Jean-François Soussana, Augustin Colette, Susanne Pfeifer, Grigory Nikulin, Laurent Menut, Klaus Keuler, Robert Vautard, Diana Rechid, Christine Radermacher, Mark Rounsevell, Arne Kriegsmann, Laurens M. Bouwer, Samuel Somot, Juliane Petersen, Andreas Haensler, Kai Radtke, Erik van Meijgaard, Bastian Eggert, Nico Kröner, Goran Georgievski, Swantje Preuschmann, Alain Braun, Bjorn Weber, Christopher Moseley, Pascal Yiou, Antoinette Alias, Claas Teichmann, Elena Georgopoulou, Ole Bøssing Christensen, Eric Martin, Daniela Jacob, Colins Jones, Sari Kovats, Nils Hempelmann, Patrick Samuelsson, Riccardo Valentini, Climate Service Center, Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Danish Climate Centre, Danish Meteorological Institute (DMI), Institute for Environmental Studies, Vrije University, Institut National de l'Environnement Industriel et des Risques (INERIS), Brandenburg University of Technology [Cottbus – Senftenberg] (BTU), Institute for Environmental Research and Sustainable Development, Wegener Center for Climate and Global Change, University of Graz, Institute for Geophysics, Astrophysics and Meteorology [Graz] (IGAM), Karl-Franzens-Universität Graz, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Swedish Meteorological and Hydrological Institute (SMHI), London School of Hygiene and Tropical Medicine (LSHTM), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Royal Netherlands Meteorological Institute (KNMI), Max Planck Institute for Meteorology (MPI-M), Max-Planck-Gesellschaft, School of GeoSciences, Institute of Geography & the Lived Environment, University of Edinburgh, Unité Mixte de Recherche sur l'Ecosystème Prairial - UMR (UREP), Institut National de la Recherche Agronomique (INRA)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS), Department of Forest Science and Environment, University of Tuscia, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Vrije Universiteit Brussel [Bruxelles] (VUB), Wegener Center for Climate and Global Change (WEGC), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), UR 0874 Unité de recherche sur l'Ecosystème Prairial, Institut National de la Recherche Agronomique (INRA)-Unité de recherche sur l'Ecosystème Prairial (UREP)-Ecologie des Forêts, Prairies et milieux Aquatiques (EFPA), Institut National de la Recherche Agronomique (INRA), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Extrèmes : Statistiques, Impacts et Régionalisation (ESTIMR), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), EU FP6 Integrated Project ENSEMBLES [505539], 7th Framework EU-project IMPACT2C [FP7-ENV.2011.1.1.6-1], 7th Framework EU-project ECLISE [FP7-ENV.2010.1.1.4-1], Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Unité de recherche sur l'Ecosystème Prairial (UREP), Università degli studi della Tuscia [Viterbo], Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Karl-Franzens-Universität [Graz, Autriche], Spatial analysis & Decision Support, and Amsterdam Global Change Institute

Subjects
010504 meteorology & atmospheric sciences, 0207 environmental engineering, Climate change, High resolution, 02 engineering and technology, REGIONAL CLIMATE CHANGE, Atmospheric sciences, 01 natural sciences, HEAVY PRECIPITATION, Regional climate change, Impact indices, EURO-CORDEX, Heat wave, Heavy precipitation, Dry spells, ddc:550, SDG 13 - Climate Action, Precipitation, Mean radiant temperature, HEAT WAVE, 020701 environmental engineering, 0105 earth and related environmental sciences, Global and Planetary Change, Impact assessment, DRY SPELLS, Data set, Earth sciences, 13. Climate action, IMPACT INDICES, Climatology, [SDE]Environmental Sciences, Environmental science, Climate model, Downscaling
Abstract

A new high-resolution regional climate change ensemble has been established for Europe within the World Climate Research Program Coordinated Regional Downscaling Experiment (EURO-CORDEX) initiative. The first set of simulations with a horizontal resolution of 12.5 km was completed for the new emission scenarios RCP4.5 and RCP8.5 with more simulations expected to follow. The aim of this paper is to present this data set to the different communities active in regional climate modelling, impact assessment and adaptation. The EURO-CORDEX ensemble results have been compared to the SRES A1B simulation results achieved within the ENSEMBLES project. The large-scale patterns of changes in mean temperature and precipitation are similar in all three scenarios, but they differ in regional details, which can partly be related to the higher resolution in EURO-CORDEX. The results strengthen those obtained in ENSEMBLES, but need further investigations. The analysis of impact indices shows that for RCP8.5, there is a substantially larger change projected for temperature-based indices than for RCP4.5. The difference is less pronounced for precipitation-based indices. Two effects of the increased resolution can be regarded as an added value of regional climate simulations. Regional climate model simulations provide higher daily precipitation intensities, which are completely missing in the global climate model simulations, and they provide a significantly different climate change of daily precipitation intensities resulting in a smoother shift from weak to moderate and high intensities., Regional Environmental Change, 14 (2), ISSN:1436-3798, ISSN:1436-378X

Published
2014
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30. Erratum to: EURO-CORDEX: new high-resolution climate change projections for European impact research

Author

Laurent Menut, Patrick Samuelsson, Diana Rechid, Andreas Gobiet, Samuel Somot, Nils Hempelmann, Christopher Moseley, Bastian Eggert, Augustin Colette, Susanne Pfeifer, Michel Déqué, Kai Radtke, Bjorn Weber, Antoinette Alias, Goran Georgievski, Claas Teichmann, Laurens M. Bouwer, Jean-François Soussana, Alain Braun, Robert Vautard, Nico Kröner, Pascal Yiou, Erik van Meijgaard, Christine Radermacher, Grigory Nikulin, Andreas Haensler, Juliane Petersen, Elena Georgopoulou, Swantje Preuschmann, Sari Kovats, Ole Bøssing Christensen, Klaus Keuler, Mark Rounsevell, Eric Martin, Daniela Jacob, Colin Jones, Arne Kriegsmann, Sven Kotlarski, Riccardo Valentini, Climate Service Center, Max Planck Institute for Meteorology (MPI-M), Max-Planck-Gesellschaft, Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Danish Climate Centre, Danish Meteorological Institute (DMI), Institute for Environmental Studies, Vrije Universiteit Brussel [Bruxelles] (VUB), Institut National de l'Environnement Industriel et des Risques (INERIS), Brandenburg University of Technology, Institute for Environmental Research and Sustainable Development, National Observatory of Athens (NOA), Institute for Geophysics, Astrophysics and Meteorology [Graz] (IGAM), Karl-Franzens-Universität Graz, Wegener Center for Climate and Global Change (WEGC), Karl-Franzens-Universität [Graz, Autriche], Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Swedish Meteorological and Hydrological Institute (SMHI), London School of Hygiene and Tropical Medicine (LSHTM), Institute for Atmospheric and Climate Science [Zürich] (IAC), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), School of Geosciences [Edinburgh], University of Edinburgh, Unité de recherche sur l'Ecosystème Prairial, Institut National de la Recherche Agronomique (INRA), Department of Forest Science and Environment, University of Tuscia, Euro–Mediterranean Center for Climate Change, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Brandenburgische Technische Universität = Brandenburg Technical University (BTU), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Unité de recherche sur l'Ecosystème Prairial (UREP), Università degli studi della Tuscia [Viterbo], Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Vrije University, Wegener Center for Climate and Global Change, University of Graz, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), and Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Global and Planetary Change, 010504 meteorology & atmospheric sciences, media_common.quotation_subject, High resolution, Art, 010501 environmental sciences, 01 natural sciences, 13. Climate action, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Climatology, Nature Conservation, Humanities, 0105 earth and related environmental sciences, media_common
Abstract

Daniela Jacob • Juliane Petersen • Bastian Eggert • Antoinette Alias • Ole Bossing Christensen • Laurens M. Bouwer • Alain Braun • Augustin Colette • Michel Deque • Goran Georgievski • Elena Georgopoulou • Andreas Gobiet • Laurent Menut • Grigory Nikulin • Andreas Haensler • Nils Hempelmann • Colin Jones • Klaus Keuler • Sari Kovats • Nico Kroner • Sven Kotlarski • Arne Kriegsmann • Eric Martin • Erik van Meijgaard • Christopher Moseley • Susanne Pfeifer • Swantje Preuschmann • Christine Radermacher • Kai Radtke • Diana Rechid • Mark Rounsevell • Patrick Samuelsson • Samuel Somot • Jean-Francois Soussana • Claas Teichmann • Riccardo Valentini • Robert Vautard • Bjorn Weber • Pascal Yiou

Published
2014
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31. L'importance d'utiliser un modèle à haute résolution pour étudier le changement climatique sur les petites îles : le cas des Petites Antilles

Author

Jean-Louis Maridet, Michel Déqué, Philippe Palany, Philippe Cantet, Ouvrages hydrauliques et hydrologie (UR OHAX), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), DIRAG, Météo France, Direction Inter-Régionale des Antilles-Guyane (DIRAG), Centre national de recherches météorologiques (CNRM), Météo France-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and Météo-France

Subjects
Wet season, Lesser Antilles, Atmospheric Science, CLIMATIC CHANGE, MODELE REGIONALISE, [SDE.MCG]Environmental Sciences/Global Changes, SCENARIO, Climate change, precipitation, lcsh:QC851-999, Oceanography, lcsh:Oceanography, PREVISION DES PLUIES, medicine, RCP scenarios, lcsh:GC1-1581, 14. Life underwater, Precipitation, PLUIE EXTREME, TEMPERATURE, ComputingMilieux_MISCELLANEOUS, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, regional climate model, Meteorology, Atmospheric Physics, Climate modelling, Seasonality, medicine.disease, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, climate change, 13. Climate action, Maximum precipitation, Climatology, General Circulation Model, CHANGEMENT CLIMATIQUE, [SDE]Environmental Sciences, Environmental science, lcsh:Meteorology. Climatology, Climate Change, Regional Climate Model, RCP Scenarios, Temperature, Climate model, Downscaling
Abstract

High-resolution climate change simulations over the Lesser Antilles are performed using the ALADIN-Climate regional climate model nested within the global model ARPEGE (Météo-France). Three sets of simulations are conducted at 10 km grid spacing for reference (1971–2000) and future climate (2071–2100) under two CMIP5 scenarios (RCP4.5 and RCP8.5). With the dynamical downscaling, islands of Lesser Antilles are considered as land by the model, whereas, for the driving model, there is only sea over the domain. Temperature and precipitation change are analysed on land and on sea separately. For temperature, the warming is greater on land than on sea, especially for the minimum daily temperature (3.2°C vs. 2.3°C for the RCP85 scenario). For precipitation, projections are less reliable because the seasonality is not well reproduced by the model. Nevertheless, simulations exhibit the fact that projections on land differ from one island to the other and disagree with those on sea notably during the wet season. This underlines the importance of the dynamical downscaling to study the climate on small islands. Statistical downscaling has been performed on the Guadeloupe Island to study changes in extreme precipitation indices. The projections provided by the regional climate model suggest an increase in extreme rainfall events: longer dry periods, a bigger annual total precipitation, more frequent very heavy daily precipitation and a stronger 1 d maximum precipitation, whereas for the driving Global Climate Model, these trends are less intense.Keywords: climate change, regional climate model, RCP scenarios, Lesser Antilles, temperature, precipitation(Published: 21 October 2014)Citation: Tellus A 2014, 66, 24065, http://dx.doi.org/10.3402/tellusa.v66.24065

Published
2014
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32. Impact of climate change on the hydrogeology of two basins in Northern France

Author

Pascal Viennot, Julien Boé, Eric Martin, A. Hachour, Florence Habets, Simon Gascoin, Laurent Terray, Agnès Ducharne, Eric Sauquet, Dominique Thiéry, Michel Déqué, Christian Pagé, Ludovic Oudin, Structure et fonctionnement des systèmes hydriques continentaux (SISYPHE), Université Pierre et Marie Curie - Paris 6 (UPMC)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Mines Paris - PSL (École nationale supérieure des mines de Paris), Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Centre d'études spatiales de la biosphère (CESBIO), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Centre de Géosciences (GEOSCIENCES), Mines Paris - PSL (École nationale supérieure des mines de Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Hydrologie-Hydraulique (UR HHLY), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), GICC REXHYSS, Université Pierre et Marie Curie - Paris 6 (UPMC)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-MINES ParisTech - École nationale supérieure des mines de Paris, CERFACS, Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), MINES ParisTech - École nationale supérieure des mines de Paris, Université Pierre et Marie Curie - Paris 6 (UPMC)-École pratique des hautes études (EPHE)-MINES ParisTech - École nationale supérieure des mines de Paris-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), and MINES ParisTech - École nationale supérieure des mines de Paris-PSL Research University (PSL)

Subjects
Hydrology, Atmospheric Science, Global and Planetary Change, 010504 meteorology & atmospheric sciences, Hydrological modelling, [SDE.MCG]Environmental Sciences/Global Changes, Global warming, 0207 environmental engineering, Climate change, FRANCE, SEINE COURS D'EAU, 02 engineering and technology, Present day, 01 natural sciences, 6. Clean water, Water resources, 13. Climate action, Environmental science, Climate model, Precipitation, SOMME BASSIN, 020701 environmental engineering, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 0105 earth and related environmental sciences, Downscaling
Abstract

[Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAU; International audience; This study presents an analysis of climate change impacts on the water resources of two basins located in Northern France, by integrating four sources of uncertainty: climate modelling, hydrological modelling, downscaling methods, and emission scenarios. The analysis focused on the evolution of the water budget, the river discharges and piezometric heads. Seven hydrological models were used, from lumped rainfall-discharge to distributed hydrogeological models, and led to quite different estimates of the water balance components. One of the hydrological models, CLSM, was found to be unable to simulate the increased water stress and was thus considered as an outlier even though it gave fair results for the present day compared to observations. Although there were large differences in the results between the models, there was a marked tendency towards a decrease of the water resource in the rivers and aquifers (on average in 2050 about -14% and -2.5 m, respectively), associated with global warming and a reduction in annual precipitation (on average in 2050 +2.1 K and -3%, respectively). The uncertainty associated to climate models was shown to clearly dominate, while the three others were about the same order of magnitude and 3 to 4 times lower. In terms of impact, the results found in this work are rather different from those obtained in a previous study, even though two of the hydrological models and one of the climate models were used in both studies. This emphasizes the need for a survey of the climatic change impact on the water resource

Published
2013
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33. The CNRM-CM5.1 global climate model: description and basic evaluation

Author

Sophie Valcke, Marie-Pierre Moine, Julie Deshayes, S. Tyteca, Ramdane Alkama, D. Salas y Melia, Serge Planton, Christophe Cassou, Alain Braun, Aurore Voldoire, Fabrice Chauvin, Elodie Fernandez, Sophie Szopa, Emilia Sanchez-Gomez, Bertrand Decharme, Eric Maisonnave, Michel Déqué, I. Beau, Hervé Douville, Gurvan Madec, Laure Coquart, S. Belamari, David Saint-Martin, Stephane Sénési, Antoinette Alias, Matthieu Chevallier, Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS), CERFACS, Météo-France [Paris], Météo France, Laboratoire de physique des océans (LPO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Modélisation du climat (CLIM), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Météo-France, Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire Midi-Pyrénées (OMP), and Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Meteorology, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.MCG]Environmental Sciences/Global Changes, 0207 environmental engineering, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], 02 engineering and technology, Atmospheric model, 01 natural sciences, Atmosphere, Troposphere, Global climate modelling, Radiative transfer, Sea ice, CMIP5, 14. Life underwater, Precipitation, 020701 environmental engineering, 0105 earth and related environmental sciences, Coupled model intercomparison project, geography, geography.geographical_feature_category, Lead (sea ice), GCM, 13. Climate action, Climatology, Environmental science
Abstract

A new version of the general circulation model CNRM-CM has been developed jointly by CNRM-GAME (Centre National de Recherches Météorologiques-Groupe d'Etudes de l'AtmosphSre Météorologique) and Cerfacs (Centre Européen de Recherche et de Formation Avancée) in order to contribute to phase 5 of the Coupled Model Intercomparison Project (CMIP5). The purpose of the study is to describe its main features and to provide a preliminary assessment of its mean climatology. CNRM-CM5.1 includes the atmospheric model ARPEGE-Climat (v5.2), the ocean model NEMO (v3.2), the land surface scheme ISBA and the sea ice model GELATO (v5) coupled through the OASIS (v3) system. The main improvements since CMIP3 are the following. Horizontal resolution has been increased both in the atmosphere (from 2.8A degrees to 1.4A degrees) and in the ocean (from 2A degrees to 1A degrees). The dynamical core of the atmospheric component has been revised. A new radiation scheme has been introduced and the treatments of tropospheric and stratospheric aerosols have been improved. Particular care has been devoted to ensure mass/water conservation in the atmospheric component. The land surface scheme ISBA has been externalised from the atmospheric model through the SURFEX platform and includes new developments such as a parameterization of sub-grid hydrology, a new freezing scheme and a new bulk parameterisation for ocean surface fluxes. The ocean model is based on the state-of-the-art version of NEMO, which has greatly progressed since the OPA8.0 version used in the CMIP3 version of CNRM-CM. Finally, the coupling between the different components through OASIS has also received a particular attention to avoid energy loss and spurious drifts. These developments generally lead to a more realistic representation of the mean recent climate and to a reduction of drifts in a preindustrial integration. The large-scale dynamics is generally improved both in the atmosphere and in the ocean, and the bias in mean surface temperature is clearly reduced. However, some flaws remain such as significant precipitation and radiative biases in many regions, or a pronounced drift in three dimensional salinity.

Published
2013
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34. The CIRCE Simulations: Regional Climate Change Projections with Realistic Representation of the Mediterranean Sea

Author

Clotilde Dubois, Michel Déqué, Adriana Carillo, Daniela Jacob, Samuel Somot, Ali Harzallah, Gianmaria Sannino, Enrico Scoccimarro, Florence Sevault, Alain Braun, Paolo Ruti, Antonio Navarra, Sandro Calmanti, Alessio Bellucci, Wilhelm May, Vincenzo Artale, Alberto Elizalde, Alessandro Dell'Aquila, Mario Adani, Antonella Sanna, Paolo Oddo, Silvio Gualdi, Blandine L'Hévéder, Laurent Li, Centro Euro-Mediterraneo per i Cambiamenti Climatici [Bologna] (CMCC), Ist Nazl Geofis & Vulcanol, Bologna, Italy, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Italian Natl Agcy New Technol Energy & Sustainabl, Rome, Italy, Max-Planck-Institut für Meteorologie (MPI-M), Max-Planck-Gesellschaft, Natl Inst Marine Sci & Technol, Salammbo, Tunisia, Danish Meteorological Institute (DMI), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Sannino, G., Dell'Aquila, A., Ruti, P., Carillo, A., Calmanti, S., Artale, V., Gualdi S, Somot S, Li L, Artale V, Adani M, Bellucci A, Braun A, Calmanti S, Carillo A, Dell'Aquila A, Deque M, Dubois C, Elizalde A, Harzallah A, Jacob D, L'Heveder B, May W, Oddo P, Ruti P, Sanna A, Sannino G, Scoccimarro E, Sevault F, and Navarra A

Subjects
Mediterranean climate, Atmospheric Science, Special Report on Emissions Scenarios, 010504 meteorology & atmospheric sciences, Climate commitment, Climate change, 010501 environmental sciences, 01 natural sciences, Regional Model, CIRCE, Mediterranean Sea, Mediterranean sea, 13. Climate action, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Climatology, Environmental science, media_common.cataloged_instance, Climate model, 14. Life underwater, Precipitation, European union, 0105 earth and related environmental sciences, media_common
Abstract

In this article, the authors describe an innovative multimodel system developed within the Climate Change and Impact Research: The Mediterranean Environment (CIRCE) European Union (EU) Sixth Framework Programme (FP6) project and used to produce simulations of the Mediterranean Sea regional climate. The models include high-resolution Mediterranean Sea components, which allow assessment of the role of the basin and in particular of the air–sea feedbacks in the climate of the region. The models have been integrated from 1951 to 2050, using observed radiative forcings during the first half of the simulation period and the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1B scenario during the second half. The projections show a substantial warming (about 1.5°–2°C) and a significant decrease of precipitation (about 5%) in the region for the scenario period. However, locally the changes might be even larger. In the same period, the projected surface net heat loss decreases, leading to a weaker cooling of the Mediterranean Sea by the atmosphere, whereas the water budget appears to increase, leading the basin to lose more water through its surface than in the past. Overall, these results are consistent with the findings of previous scenario simulations, such as the Prediction of Regional Scenarios and Uncertainties for Defining European Climate Change Risks and Effects (PRUDENCE), Ensemble-Based Predictions of Climate Changes and Their Impacts (ENSEMBLES), and phase 3 of the Coupled Model Intercomparison Project (CMIP3). The agreement suggests that these findings are robust to substantial changes in the configuration of the models used to make the simulations. Finally, the models produce a 2021–50 mean steric sea level rise that ranges between +7 and +12 cm, with respect to the period of reference.

Published
2013
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35. The simulation of European heat waves from an ensemble of regional climate models within the EURO-CORDEX project

Author

Tomas Halenka, Ivan Güttler, Michel Déqué, Erik van Meijgaard, Grigory Nikulin, Martin Suklitsch, Robert Vautard, Volker Wulfmeyer, Andreas Gobiet, Theodore Karacostas, Augustin Colette, Markel García-Díez, Michal Belda, Mirta Patarčić, Klaus Goergen, Jesús Fernández, Pascal Yiou, Eleni Katragkou, Stephanie Mayer, Kirsten Warrach-Sagi, Klaus Keuler, John Scinocca, Sven Kotlarski, Daniela Jacob, Stefan Sobolowski, Claas Teichmann, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Extrèmes : Statistiques, Impacts et Régionalisation (ESTIMR), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Wegener Center for Climate and Global Change (WEGC), Karl-Franzens-Universität Graz, Institute for Geophysics, Astrophysics and Meteorology [Graz] (IGAM), Climate Service Center, Department of Meteorology and Environment Protection, Charles University [Prague] (CU), Institut National de l'Environnement Industriel et des Risques (INERIS), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Department Applied Mathematics and Computer Science, Universidad de Cantabria [Santander], Instituto de Fisica de Cantabria, Instituto de Física de Cantabria, Centre de Recherche Public - Gabriel Lippmann (LUXEMBOURG), Croatian Meteorological and Hydrological Service (DHMZ), Aristotelian University of Thessaloniki, Aristotle University of Thessaloniki, Brandenburg University of Technology [Cottbus – Senftenberg] (BTU), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Bjerknes Centre for Climate Research (BCCR), Department of Biological Sciences [Bergen] (BIO / UiB), University of Bergen (UiB)-University of Bergen (UiB), Royal Netherlands Meteorological Institute (KNMI), Swedish Meteorological and Hydrological Institute (SMHI), Canadian Centre for Climate Modelling and Analysis (CCCma), Environment and Climate Change Canada, Max Planck Institute for Meteorology (MPI-M), Max-Planck-Gesellschaft, Institute of Physics and Meteorology [Stuttgart] (IPM), University of Hohenheim, European Commission, Fonds National de la Recherche Luxembourg, Ministerio de Ciencia e Innovación (España), Charles University (Czech Republic), Deutsche Forschungsgemeinschaft, Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Karl-Franzens-Universität [Graz, Autriche], Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), and German Research Foundation

Subjects
Convection, Atmospheric Science, Percentile, 010504 meteorology & atmospheric sciences, 0207 environmental engineering, Scale (descriptive set theory), 02 engineering and technology, 01 natural sciences, Heat waves, Hot Temperature, Climate projections, Precipitation, Bowen ratio, 020701 environmental engineering, Model evaluation, 0105 earth and related environmental sciences, Microphysics, Regional climate modeling, regional climate modeling, heat waves, model evaluation, climate projection, EURO-CORDEX, Climate projection, 13. Climate action, Climatology, [SDE]Environmental Sciences, Environmental science, Climate model
Abstract

The ability of a large ensemble of regional climate models to accurately simulate heat waves at the regional scale of Europe was evaluated. Within the EURO-CORDEX project, several state-of-the art models, including non-hydrostatic meso-scale models, were run for an extended time period (20 years) at high resolution (12 km), over a large domain allowing for the first time the simultaneous representation of atmospheric phenomena over a large range of spatial scales. Eight models were run in this configuration, and thirteen models were run at a classical resolution of 50 km. The models were driven with the same boundary conditions, the ERA-Interim re-analysis, and except for one simulation, no observations were assimilated in the inner domain. Results, which are compared with daily temperature and precipitation observations (ECA&D and E-OBS data sets) show that, even forced by the same re-analysis, the ensemble exhibits a large spread. A preliminary analysis of the sources of spread, using in particular simulations of the same model with different parameterizations, shows that the simulation of hot temperature is primarily sensitive to the convection and the microphysics schemes, which affect incoming energy and the Bowen ratio. Further, most models exhibit an overestimation of summertime temperature extremes in Mediterranean regions and an underestimation over Scandinavia. Even after bias removal, the simulated heat wave events were found to be too persistent, but a higher resolution reduced this deficiency. The amplitude of events as well as the variability beyond the 90th percentile threshold were found to be too strong in almost all simulations and increasing resolution did not generally improve this deficiency. Resolution increase was also shown to induce large-scale 90th percentile warming or cooling for some models, with beneficial or detrimental effects on the overall biases. Even though full causality cannot be established on the basis of this evaluation work, the drivers of such regional differences were shown to be linked to changes in precipitation due to resolution changes, affecting the energy partitioning. Finally, the inter-annual sequence of hot summers over central/southern Europe was found to be fairly well simulated in most experiments despite an overestimation of the number of hot days and of the variability. The accurate simulation of inter-annual variability for a few models is independent of the model bias. This indicates that internal variability of high summer temperatures should not play a major role in controlling inter-annual variability. Despite some improvements, especially along coastlines, the analyses conducted here did not allow us to generally conclude that a higher resolution is clearly beneficial for a correct representation of heat waves by regional climate models. Even though local-scale feedbacks should be better represented at high resolution, combinations of parameterizations have to be improved or adapted accordingly. © 2013 Springer-Verlag Berlin Heidelberg., The EURO-CORDEX simulations and analysis were carried out in several groups within the framework of the IMPACT2C FP7 project (Grant FP7-ENV.2011.1.1.6-1). The BTU Cottbus offered an exchange ftp site for sharing all model simulation files. The contribution from CRP-GL was funded by the Luxembourg National Research Fund (FNR) through Grant FNR C09/SR/16 (CLIMPACT). We acknowledge financial support from the Spanish R&D program through Grants CGL2010-21869 (EXTREMBLES) and CGL2010-22158-C02-01 (CORWES). Charles University runs were supported partially in framework of the Research Plan of MSMT (No. MSM 0021620860) and GACR project No. P209/11/2405. The contribution from UHOH was funded by the German Science Foundation (DFG) through project FOR 1695. The REMO simulations were supported by CSC, MPI, as well as BMBF and performed under the ‘‘Konsortial’’ share at the German Climate Computing Centre (DKRZ), as well as the CCLM simulations carried out by BTU, which we are further thankful for their various support. We are thankful to the French CCRT/TGCC supercomputing center support and the CEA and GENCI computing resource allocation agency for the WRF-IPSL-INERIS runs. The development of the modeling chain at INERIS and IPSL was carried out in part within the French national project SALUT’AIR (PRIMEQUAL research program). Part of SMHI contribution was done in the ECLISE projects that receive funding from the European Union Seventh Framework Programme (FP7/2007–2013) under Grant agreement 265240 and in the Swedish Mistra-SWECIA programme founded by Mistra (the Foundation for Strategic Environmental Research). DHMZ contribution was partially supported by the Croatian Ministry of Science, Education and Sports (Grant No. 004-1193086-3035).

Published
2013
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36. Future projections of the surface heat and water budgets of the Mediterranean Sea in an ensemble of coupled atmosphere–ocean regional climate models

Author

Daniela Jacob, Gianmaria Sannino, Blandine L'Hévéder, A. Dell'Aquilla, Clotilde Dubois, Adriana Carillo, Samuel Somot, Silvio Gualdi, Michel Déqué, Paolo Oddo, Alberto Elizalde, Enrico Scoccimarro, Florence Sevault, Laurent Li, Sandro Calmanti, Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Max Planck Institute for Meteorology (MPI-M), Max-Planck-Gesellschaft, Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Bologna (INGV), Istituto Nazionale di Geofisica e Vulcanologia, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Agenzia Nazionale per le nuove Tecnologie, l’energia e lo sviluppo economico sostenibile = Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Cloud cover, 0207 environmental engineering, Climate commitment, Climate change, 02 engineering and technology, [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology, 01 natural sciences, Sea surface temperature, Mediterranean sea, 13. Climate action, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Climatology, Greenhouse gas, Climate change scenario, Environmental science, Climate model, 020701 environmental engineering, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract

International audience; Within the CIRCE project "Climate change and Impact Research: the Mediterranean Environment", an ensemble of high resolution coupled atmosphere-ocean regional climate models (AORCMs) are used to simulate the Mediterranean climate for the period 1950-2050. For the first time, realistic net surface air-sea fluxes are obtained. The sea surface temperature (SST) variability is consistent with the atmospheric forcing above it and oceanic constraints. The surface fluxes respond to external forcing under a warming climate and show an equivalent trend in all models. This study focuses on the present day and on the evolution of the heat and water budget over the Mediterranean Sea under the SRES-A1B scenario. On the contrary to previous studies, the net total heat budget is negative over the present period in all AORCMs and satisfies the heat closure budget controlled by a net positive heat gain at the strait of Gibraltar in the present climate. Under climate change scenario, some models predict a warming of the Mediterranean Sea from the ocean surface (positive net heat flux) in addition to the positive flux at the strait of Gibraltar for the 2021-2050 period. The shortwave and latent flux are increasing and the longwave and sensible fluxes are decreasing compared to the 1961-1990 period due to a reduction of the cloud cover and an increase in greenhouse gases (GHGs) and SSTs over the 2021-2050 period. The AORCMs provide a good estimates of the water budget with a drying of the region during the twenty-first century. For the ensemble mean, he decrease in precipitation and runoff is about 10 and 15% respectively and the increase in evaporation is much weaker, about 2% compared to the 1961-1990 period which confirm results obtained in recent studies. Despite a clear consistency in the trends and results between the models, this study also underlines important differences in the model set-ups, methodology and choices of some physical parameters inducing some difference in the various air-sea fluxes. An evaluation of the uncertainty sources and possible improvement for future generation of AORCMs highlights the importance of the parameterisation of the ocean albedo, rivers and cloud cover. © 2011 Springer-Verlag.

Published
2012
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37. Statistical adaptation of ALADIN RCM outputs over the French Alps - application to future climate and snow cover

Author

Gérald Giraud, Laurent Mérindol, Hélène Castebrunet, M. Rousselot, Yves Durand, Michel Déqué, Ingrid Dombrowski-Etchevers, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Ecosystèmes méditerranéens et risques (UR EMAX), and Centre national du machinisme agricole, du génie rural, des eaux et forêts (CEMAGREF)

Subjects
010504 meteorology & atmospheric sciences, Cloud cover, 0207 environmental engineering, Climate change, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 02 engineering and technology, [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology, 01 natural sciences, Shortwave radiation, Precipitation, 020701 environmental engineering, lcsh:Environmental sciences, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, lcsh:GE1-350, lcsh:QE1-996.5, Longwave, Snowpack, Snow, lcsh:Geology, 13. Climate action, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Climatology, Environmental science, Climate model
Abstract

In this study, snowpack scenarios are modelled across the French Alps using dynamically downscaled variables from the ALADIN Regional Climate Model (RCM) for the control period (1961–1990) and three emission scenarios (SRES B1, A1B and A2) for the mid- and late 21st century (2021–2050 and 2071–2100). These variables are statistically adapted to the different elevations, aspects and slopes of the Alpine massifs. For this purpose, we use a simple analogue criterion with ERA40 series as well as an existing detailed climatology of the French Alps (Durand et al., 2009a) that provides complete meteorological fields from the SAFRAN analysis model. The resulting scenarios of precipitation, temperature, wind, cloudiness, longwave and shortwave radiation, and humidity are used to run the physical snow model CROCUS and simulate snowpack evolution over the massifs studied. The seasonal and regional characteristics of the simulated climate and snow cover changes are explored, as is the influence of the scenarios on these changes. Preliminary results suggest that the snow water equivalent (SWE) of the snowpack will decrease dramatically in the next century, especially in the Southern and Extreme Southern parts of the Alps. This decrease seems to result primarily from a general warming throughout the year, and possibly a deficit of precipitation in the autumn. The magnitude of the snow cover decline follows a marked altitudinal gradient, with the highest altitudes being less exposed to climate change. Scenario A2, with its high concentrations of greenhouse gases, results in a SWE reduction roughly twice as large as in the low-emission scenario B1 by the end of the century. This study needs to be completed using simulations from other RCMs, since a multi-model approach is essential for uncertainty analysis.

Published
2012
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38. The spread amongst ENSEMBLES regional scenarios: regional climate models, driving general circulation models and interannual variability

Author

Daniela Jacob, Samuel Somot, Michel Déqué, Clare Goodess, Geert Lenderink, Ole Bøssing Christensen, and Emilia Sanchez-Gomez

Subjects
Atmospheric Science, Climatology, Greenhouse gas, Environmental science, Climate change, Sampling (statistics), Climate model, Precipitation, Variance (accounting), Expected value, Explained variation, Atmospheric sciences
Abstract

Various combinations of thirteen regional climate models (RCM) and six general circulation models (GCM) were used in FP6-ENSEMBLES. The response to the SRES-A1B greenhouse gas concentration scenario over Europe, calculated as the difference between the 2021-2050 and the 1961-1990 means can be viewed as an expected value about which various uncertainties exist. Uncertainties are measured here by variance explained for temperature and precipitation changes over eight European sub-areas. Three sources of uncertainty can be evaluated from the ENSEMBLES database. Sampling uncertainty is due to the fact that the model climate is estimated as an average over a finite number of years (30) despite a non-negligible interannual variability. Regional model uncertainty is due to the fact that the RCMs use different techniques to discretize the equations and to represent sub-grid effects. Global model uncertainty is due to the fact that the RCMs have been driven by different GCMs. Two methods are presented to fill the many empty cells of the ENSEMBLES RCM × GCM matrix. The first one is based on the same approach as in FP5-PRUDENCE. The second one uses the concept of weather regimes to attempt to separate the contribution of the GCM and the RCM. The variance of the climate response is analyzed with respect to the contribution of the GCM and the RCM. The two filling methods agree that the main contributor to the spread is the choice of the GCM, except for summer precipitation where the choice of the RCM dominates the uncertainty. Of course the implication of the GCM to the spread varies with the region, being maximum in the South-western part of Europe, whereas the continental parts are more sensitive to the choice of the RCM. The third cause of spread is systematically the interannual variability. The total uncertainty about temperature is not large enough to mask the 2021-2050 response which shows a similar pattern to the one obtained for 2071-2100 in PRUDENCE. The uncertainty about precipitation prevents any quantitative assessment on the response at grid point level for the 2021-2050 period. One can however see, as in PRUDENCE, a positive response in winter (more rain in the scenario than in the reference) in northern Europe and a negative summer response in southern Europe. © 2011 The Author(s).

Published
2012
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39. Impact du changement climatique sur les vagues et la dérive littorale le long du littoral aquitain

Author

Gonéri Le Cozannet, Elodie Charles, Déborah Idier, Pascale Delecluse, Michel Déqué, Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Fondation AXA pour la recherche, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, modelling, climate change, 010504 meteorology & atmospheric sciences, 13. Climate action, Aquitanian coast, 010604 marine biology & hydrobiology, waves, 01 natural sciences, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Water Science and Technology, sediment transport
Abstract

La dynamique sedimentaire littorale est controlee par un ensemble de facteurs hydrodynamiques qui sont susceptibles d’etre modifies par le changement climatique. Les vagues ont un role dominant dans la dynamique du littoral aquitain. Afin d’analyser l’impact du changement climatique, un modele de vagues est mis en place et des simulations sont realisees pour les climats actuel (1961-2000) et futurs (2061-2100). L’analyse des futures conditions de vague dans le Golfe de Gascogne met en evidence une diminution generalisee des hauteurs de vague et une rotation horaire de l’ensemble des vagues estivales et des houles hivernales par rapport au climat actuel. Le long de la cote aquitaine, la diminution des hauteurs de vague est toujours significative. Cependant, la refraction bathymetrique induit une attenuation de la rotation des vagues, en particulier des houles hivernales. Le calcul de la derive littorale (aussi appelee flux de sediment longshore ) au niveau de la plage de Biscarrosse a partir de formules empiriques indique que ces changements resulteraient en une diminution des flux longshore pouvant atteindre 10 %. Cette diminution est associee a la diminution des hauteurs de vague a proximite de la cote. Enfin, l’inventaire des incertitudes liees aux differentes etapes de cette etude suggere des pistes d’amelioration de la quantification des futurs flux de sediment, par exemple en considerant davantage de modeles climatiques ou en modelisant les vagues dans la zone de deferlement.

Published
2012
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40. On the comparison between two sets of 500 mb geopotential height eigenfunctions

Author

Michel Déqué

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Meteorology, 010505 oceanography, Mathematical analysis, Northern Hemisphere, Magnitude (mathematics), Geopotential height, Empirical orthogonal functions, Eigenfunction, Oceanography, 01 natural sciences, Linear subspace, Eigenvalues and eigenvectors, 0105 earth and related environmental sciences, Mathematics
Abstract

When the largest eigenvalues of an Empirical Orthogonal Function (EOF) analysis are of similar magnitude, the corresponding EOFs do not hold great interest when they are considered one at a time; only the vector subspace generated by the first EOFs is significant. In this case, the comparison between two EOF analyses may be summarized by a distance index between the two subspaces. Such a method is applied to EOF analyses over the northern hemisphere of the 500 mb geopotential height from 10 winters of simulation (using a version of the ECMWF spectral model) and 13 observed winters. For more than the first three low-order EOFs, the agreement between simulation and observation is statistically significant. DOI: 10.1111/j.1600-0870.1986.tb00477.x

Published
2011

41. Seasonal predictability of tropical rainfall: probabilistic formulation and validation

Author

Michel Déqué

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, 010505 oceanography, Probabilistic logic, Forecast skill, Variance (accounting), Empirical probability, Oceanography, 01 natural sciences, Forecast verification, Climatology, Quantitative precipitation forecast, Predictability, Consensus forecast, 0105 earth and related environmental sciences, Mathematics
Abstract

Two idealized seasonal forecast experiments are performed by prescribing monthly observed SSTs to atmospheric GCMs. The first one uses 3 different models, each with 9 individual forecasts (PROVOST experiment). The second one uses an improved version of one of the 3 models and larger ensembles consisting of 120 members. Both experiments show that forecast scores are maximum in the tropics during winter and during summer. The relatively high correlations in the tropics (0.4 to 0.7) imply, however, that the forecasts explain less than 50% of the variance of the observations. The raw probabilistic forecasts obtained by the empirical probability distribution of the forecast members exhibit very little skill, when evaluated by a euclidian distance versus the climatological forecast. The lack of reliability can be partly corrected by a simple statistical adaptation. Moreover, when the skill is evaluated by an economical value in a cost/loss approach, the model forecasts are more efficient than the climatological forecast. A more realistic evaluation of the probabilistic skill is obtained by replacing observed by statistically predicted SSTs. A simple but efficient method is used, which lets each member of the ensemble develop its own SST anomalies. Although lower, skill is significant in the tropics. DOI: 10.1111/j.1600-0870.2001.00500.x

Published
2011

42. Tropical influence on boreal summer mid-latitude stationary waves

Author

Nicholas M. J. Hall, Christophe Cassou, Hervé Douville, Soline Bielli, S. Tyteca, Michel Déqué, Aurore Voldoire, Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS), CERFACS, Océan du Large et Variabilité Climatique (OLVAC), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Atmospheric Science, 010504 meteorology & atmospheric sciences, Atmospheric circulation, 010502 geochemistry & geophysics, Atmospheric sciences, 01 natural sciences, African easterly jet, Sea surface temperature, 13. Climate action, Anticyclone, Climatology, Middle latitudes, Extratropical cyclone, Environmental science, Climate model, 0105 earth and related environmental sciences, Teleconnection
Abstract

International audience; While organized tropical convection is a well-known source of extratropical planetary waves, state-of-the-art climate models still show serious deficiencies in simulating accurately the atmospheric response to tropical sea surface temperature (SST) anomalies and the associated teleconnections. In the present study, the remote influence of the tropical atmospheric circulation is evaluated in ensembles of global boreal summer simulations in which the Arpege-Climat atmospheric General Circulation Model (GCM) is nudged towards 6-h reanalyses. The nudging is applied either in the whole tropical band or in a regional summer monsoon domain. Sensitivity tests to the experimental design are first conducted using prescribed climatological SST. They show that the tropical relaxation does not improve the zonal mean extratropical climatology but does lead to a significantly improved representation of the mid-latitude stationary waves in both hemispheres. Low-pass filtering of the relaxation fields has no major effect on the model response, suggesting that high-frequency tropical variability is not responsible for extratropical biases. Dividing the nudging strength by a factor 10 only decreases the magnitude of the response. Model errors in each monsoon domain contribute to deficiencies in the model's mid-latitude climatology, although an exaggerated large-scale subsidence in the central equatorial Pacific appears as the main source of errors for the representation of stationary waves in the Arpege-Climat model. Case studies are then conducted using either climatological or observed SST. The focus is first on summer 2003 characterized by a strong and persistent anticyclonic anomaly over western Europe. This pattern is more realistic in nudging experiments than in simulations only driven by observed SST, especially when the nudging domain is centred over Central America. Other case studies also show a significant tropical forcing of the summer mid-latitude stationary waves and suggest a weak influence of prescribed observed SST in the northern extratropics. Results therefore indicate that improving the tropical divergent circulation and its response to tropical SST anomalies remains a key issue for increasing the skill of extratropical seasonal predictions, not only in the winter hemisphere but also in the boreal summer hemisphere where the prediction of heatwave and drought likelihood is expected to become an important challenge with increasing concentrations of greenhouse gases.

Published
2011
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43. Evaluation of Probabilistic Quality and Value of the ENSEMBLES Multimodel Seasonal Forecasts: Comparison with DEMETER

Author

Alberto Arribas, Philippe Rogel, Michel Déqué, Antje Weisheimer, Antonio Navarra, Andrea Borrelli, Andrea Alessandri, Alessandri A, Borrelli A, Navarra A, Arribas A, Deque M, Rogel P, and Weisheimer A

Subjects
Atmospheric Science, geography, geography.geographical_feature_category, Meteorology, Probabilistic logic, Initialization, Climate change, Forecast skill, Forcing (mathematics), Greenhouse gas, Climatology, Sea ice, Environmental science, ensemble, seasonal forecasting, Predictability
Abstract

The performance of the new multimodel seasonal prediction system developed in the framework of the European Commission FP7 project called ENSEMBLE-based predictions of climate changes and their impacts (ENSEMBLES) is compared with the results from the previous project [i.e., Development of a European Multimodel Ensemble System for Seasonal-to-Interannual Prediction (DEMETER)]. The comparison is carried out over the five seasonal prediction systems (SPSs) that participated in both projects. Since DEMETER, the contributing SPSs have improved in all aspects with the main advancements including the increase in resolution, the better representation of subgrid physical processes, land, sea ice, and greenhouse gas boundary forcing, and the more widespread use of assimilation for ocean initialization. The ENSEMBLES results show an overall enhancement for the prediction of anomalous surface temperature conditions. However, the improvement is quite small and with considerable space–time variations. In the tropics, ENSEMBLES systematically improves the sharpness and the discrimination attributes of the forecasts. Enhancements of the ENSEMBLES resolution attribute are also reported in the tropics for the forecasts started 1 February, 1 May, and 1 November. Our results indicate that, in ENSEMBLES, an increased portion of prediction signal from the single-models effectively contributes to amplify the multimodel forecasts skill. On the other hand, a worsening is shown for the multimodel calibration over the tropics compared to DEMETER. Significant changes are also shown in northern midlatitudes, where the ENSEMBLES multimodel discrimination, resolution, and reliability improve for February, May, and November starting dates. However, the ENSEMBLES multimodel decreases the capability to amplify the performance with respect to the contributing single models for the forecasts started in February, May, and August. This is at least partly due to the reduced overconfidence of the ENSEMBLES single models with respect to the DEMETER counterparts. Provided that they are suitably calibrated beforehand, it is shown that the ENSEMBLES multimodel forecasts represent a step forward for the potential economical value they can supply. A warning for all potential users concerns the need for calibration due to the degraded tropical reliability compared to DEMETER. In addition, the superiority of recalibrating the ENSEMBLES predictions through the discrimination information is shown. Concerning the forecasts started in August, ENSEMBLES exhibits mixed results over both tropics and northern midlatitudes. In this case, the increased potential predictability compared to DEMETER appears to be balanced by the reduction in the independence of the SPSs contributing to ENSEMBLES. Consequently, for the August start dates no clear advantage of using one multimodel system instead of the other can be evidenced.

Published
2011

44. DRIAS: a step toward Climate Services in France

Author

M. Kerdoncuff, J. Lémond, Thomas Noël, Serge Planton, L. Franchistéguy, J. M. Moisselin, S. Geindre, Ph. Dandin, Y. M. Tourre, Robert Vautard, C. Pagé, Michel Déqué, Laurent Li, Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Extrèmes : Statistiques, Impacts et Régionalisation (ESTIMR), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), CERFACS [Toulouse], Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS), École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL)

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Best practice, 0207 environmental engineering, Climate change, 02 engineering and technology, lcsh:QC851-999, 7. Clean energy, 01 natural sciences, 12. Responsible consumption, Order (exchange), Multidisciplinary approach, 11. Sustainability, 020701 environmental engineering, Adaptation (computer science), lcsh:Science, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Environmental planning, 0105 earth and related environmental sciences, Sustainable development, Database server, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Ecological Modeling, Pollution, lcsh:QC1-999, Geophysics, Data access, 13. Climate action, lcsh:Q, lcsh:Meteorology. Climatology, Business, lcsh:Physics
Abstract

DRIAS (Providing access to Data on French Regionalized climate scenarios and Impacts on the environment and Adaptation of Societies) is a 2-yr project (2010–2012). It is funded by the GICC (Management and Impact of Climate Change) program of the French Ministry of Ecology, Sustainable Development, Transportation, and Housing (MEDDTL). DRIAS is to provide easy access to French regional climate data and products in order to facilitate mitigation and adaptation studies. The DRIAS project focuses on existing French regional climate projections obtained from national modelling groups such as: IPSL, CERFACS, and CNRM. It is more than a data server, it also delivers all kinds of climate information from numerical data to tailored climate products. Moreover, guidance is to be provided to end-users in order to promote best practices and know-how. Whilst the project is coordinated by the Department of Climatology at Météo-France, a multidisciplinary group of users and stakeholders at large concerned by climate change issues is also involved with the project. The ultimate goal will be to identify societal needs, validate the decision making processes, and thus facilitate exchanges between producers and practitioners. Key results from the DRIAS project will contribute to the implementation of French Climate Services.

Published
2011
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45. Climate change evolution of the hydrological balance of the Mediterranean, Black and Caspian Seas: impact of climate model resolution

Author

Michel Déqué, Samuel Somot, Nellie Elguindi, Wolfgang Ludwig, Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Météo France, Centre de formation et de recherche sur l'environnement marin (CEFREM), Université de Perpignan Via Domitia (UPVD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Météo-France Direction Interrégionale Sud-Est (DIRSE), and Météo-France

Subjects
Mediterranean climate, Atmospheric Science, 010504 meteorology & atmospheric sciences, Resolution (electron density), 0207 environmental engineering, Climate change, Magnitude (mathematics), 02 engineering and technology, 01 natural sciences, 13. Climate action, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Climatology, Environmental science, Climate model, Precipitation, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, 020701 environmental engineering, Surface runoff, 0105 earth and related environmental sciences, Downscaling
Abstract

International audience; In this study we have evaluated the ability of the CNRM-ARPEGE CLIMATE V4 general circulation model (GCM) to estimate the present-day hydrological budget components [precipitation minus evaporation over the sea (P − E) and fresh water runoff (R)] over the Mediterranean, Black and Caspian sea basins. Three simulations were performed which were exactly identical except for horizontal resolution, allowing for a unique opportunity to isolate and study the effects of resolution on simulating the hydrological components. Model calculated values of runoff and P − E were compared to a variety of data sources and show that the model's performance improves significantly with increased resolution, especially in regions with mountainous terrain. Corresponding future climate simulations (following the IPCC A2 scenario) were also performed and indicate that while resolution does not seem to have a significant effect on the qualitative impacts of future climate change on the hydrologic balance, quantitatively the results vary significantly among the models. These results suggests that high resolution global models, or downscaling models such as RCMs, are necessary in order to assess the magnitude of future changes in the hydrological components of these basins.

Published
2011
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46. ENSEMBLES: A new multi-model ensemble for seasonal-to-annual predictions-Skill and progress beyond DEMETER in forecasting tropical Pacific SSTs

Author

Noel Keenlyside, P. Rogel, Andrea Alessandri, Antonio Navarra, Francisco J. Doblas-Reyes, M. MacVean, Michel Déqué, Antje Weisheimer, Alberto Arribas, Tim Palmer, Weisheimer A, Doblas-Reyes FJ, Palmer TN, Alessandri A, Arribas A, Deque M, Keenlyside N, MacVean M, Navarra A, and Rogel P

Subjects
Tropical pacific, 010504 meteorology & atmospheric sciences, Meteorology, Anomaly (natural sciences), 0207 environmental engineering, Probabilistic logic, Forecast skill, 02 engineering and technology, seasonal forecasts, ensemble, 01 natural sciences, Sea surface temperature, Geophysics, Climatology, Range (statistics), General Earth and Planetary Sciences, Environmental science, Hindcast, Statistical dispersion, 020701 environmental engineering, 0105 earth and related environmental sciences
Abstract

A new 46-year hindcast dataset for seasonal-to-annual ensemble predictions has been created using a multi-model ensemble of 5 state-of-the-art coupled atmosphere-ocean circulation models. The multi-model outperforms any of the single-models in forecasting tropical Pacific SSTs because of reduced RMS errors and enhanced ensemble dispersion at all lead-times. Systematic errors are considerably reduced over the previous generation (DEMETER). Probabilistic skill scores show higher skill for the new multi-model ensemble than for DEMETER in the 4-6 month forecast range. However, substantially improved models would be required to achieve strongly statistical significant skill increases. The combination of ENSEMBLES and DEMETER into a grand multi-model ensemble does not improve the forecast skill further. Annual-range hindcasts show anomaly correlation skill of similar to 0.5 up to 14 months ahead. A wide range of output from the multi-model simulations is becoming publicly available and the international community is invited to explore the full scientific potential of these data. Citation: Weisheimer, A., F. J. Doblas-Reyes, T. N. Palmer, A. Alessandri, A. Arribas, M. Deque, N. Keenlyside, M. MacVean, A. Navarra, and P. Rogel (2009), ENSEMBLES: A new multi-model ensemble for seasonal-to-annual predictions-Skill and progress beyond DEMETER in forecasting tropical Pacific SSTs, Geophys. Res. Lett., 36, L21711, doi:10.1029/2009GL040896.

Published
2009

47. Spectral nudging in a spectral regional climate model

Author

Samuel Somot, Raluca Radu, Michel Déqué, Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), and Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS)

Subjects
021110 strategic, defence & security studies, Atmospheric Science, 010504 meteorology & atmospheric sciences, Meteorology, 010505 oceanography, 0211 other engineering and technologies, High resolution, 02 engineering and technology, [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology, Oceanography, 01 natural sciences, Scale interaction, 13. Climate action, Environmental science, Climate model, Precipitation, Regional model, Representation (mathematics), ComputingMilieux_MISCELLANEOUS, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, Quantile, Downscaling
Abstract

Spectral nudging, a dynamic downscaling method, has been used as a suitable approach to force a regional model to adopt prescribed large-scales over the entire domain, not just at the lateral boundaries, while developing realistic detailed regional features consistent with the large-scales. The aim of this study is to compare a global spectral climate model at high resolution (50 km) and a driven spectral regional climate model over Europe by using the so-called perfect model approach. The spectral nudging method is applied in order to achieve a better representation of large-scale climate over a limited domain. The results show that the regional model driven only at its lateral boundaries presents a summer warm bias in the middle of the domain. This bias disappears when spectral nudging is applied. On the other hand, the smallest scales which are not driven by the spectral nudging are not significantly affected by scale interaction. The only detrimental impact of spectral nudging is a slight precipitation increase in the upper quantiles of precipitation, which can be resolved by large-scale nudging of specific humidity.

Published
2008

48. Expected impacts of climate change on extreme climate events

Author

Serge Planton, Michel Déqué, Laurent Terray, Fabrice Chauvin, Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS), and CERFACS

Subjects
Changement climatique, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Global and Planetary Change, 010504 meteorology & atmospheric sciences, Extremes, Climate commitment, Climate change, Storm, 010501 environmental sciences, [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology, 01 natural sciences, Événements extrêmes, 13. Climate action, Effects of global warming, Climatology, Greenhouse gas, Abrupt climate change, General Earth and Planetary Sciences, Environmental science, Precipitation, 0105 earth and related environmental sciences, Downscaling
Abstract

Résumé : Impacts du changement climatique sur les événements climatiques extrêmes. Nous présentons, dans cet article, une revue des changements attendus au cours de ce siècle sur les extrêmes climatiques, du fait des émissions anthropiques de gaz à effet de serre et d'aérosols. Les méthodologies les plus couramment utilisées reposent sur la descente d'échelle dynamique ou statistique des projections climatiques réalisées à partir de modèles de circulation générale atmosphériques et océaniques couplés. Qu'elles soient de type statistique ou dynamique, les méthodes de descente d'échelle présentent des forces et des faiblesses, mais ni leur validation sur les conditions du climat actuel, ni leur capacité potentielle à projeter l'impact du changement climatique sur les statistiques des événements extrêmes ne permet de donner un avantage spécifique à l'un des deux types. Les résultats synthétisés dans le dernier rapport du GIEC et des études plus récentes soulignent une convergence, pour une très probable augmentation des épisodes de vague de chaleur au-dessus des surfaces continentales, liée au réchauffement moyen et à l'augmentation de la variabilité de la température. De plus, le nombre de jours de gel devrait décroître et la saison de croissance s'allonger. L'accroissement projeté des événements de précipitations intenses apparaît aussi très probable sur la plupart des régions et semble aussi lié à un changement de la forme de la fonction de distribution de l'intensité des précipitations. Les tendances globales sur la durée des sécheresses sont moins cohérentes entre les différents modèles ou suivant les différentes méthodes de descente d'échelle, du fait de leur variabilité régionale. Les changements des extrêmes liés au vent sont aussi dépendants de la région et sont associés à un déplacement, vers les poles, des trajectoires des dépressions des moyennes latitudes. L'étude spécifique des événements extrêmes en France révèle la forte sensibilité de certaines statistiques des extrêmes climatiques à l'échelle de temps décennales du fait de la variabilité interne du climat à l'échelle régionale.; International audience; An overview of the expected change of climate extremes during this century due to greenhouse gases and aerosol anthropogenic emissions is presented. The most commonly used methodologies rely on the dynamical or statistical downscaling of climate projections, performed with coupled atmosphere–ocean general circulation models. Either of dynamical or of statistical type, downscaling methods present strengths and weaknesses, but neither their validation on present climate conditions, nor their potential ability to project the impact of climate change on extreme event statistics allows one to give a specific advantage to one of the two types. The results synthesized in the last IPCC report and more recent studies underline a convergence for a very likely increase in heat wave episodes over land surfaces, linked to the mean warming and the increase in temperature variability. In addition, the number of days of frost should decrease and the growing season length should increase. The projected increase in heavy precipitation events appears also as very likely over most areas and also seems linked to a change in the shape of the precipitation intensity distribution. The global trends for drought duration are less consistent between models and downscaling methodologies, due to their regional variability. The change of wind-related extremes is also regionally dependent, and associated to a poleward displacement of the midlatitude storm tracks. The specific study of extreme events over France reveals the high sensitivity of some statistics of climate extremes at the decadal time scale as a consequence of regional climate internal variability.

Published
2008

49. Impacts of climate change on temperate forests and interaction with management

Author

Denis Loustau, Jérôme Ogée, Michel Déqué, Jean-Luc Dupouey, Vincent BADEAU, Nicolas Viovy, Philippe Ciais, Marie Laure Desprez Loustau, Alain Roques, Isabelle Chuine, Florent Mouillot, ProdInra, Migration, Peter Freer-Smith (Editeur), Mark Broadmeadow (Editeur), Jim Lynch (Editeur), Écologie fonctionnelle et physique de l'environnement (EPHYSE), Institut National de la Recherche Agronomique (INRA), Météo France, Ecologie et Ecophysiologie Forestières [devient SILVA en 2018] (EEF), Institut National de la Recherche Agronomique (INRA)-Université de Lorraine (UL), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Biodiversité, Gènes & Communautés (BioGeCo), Institut National de la Recherche Agronomique (INRA)-Université de Bordeaux (UB), Unité de recherche Zoologie Forestière (URZF), Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Université Paul-Valéry - Montpellier 3 (UPVM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut de Recherche pour le Développement (IRD [France-Sud]), Institut de Recherche pour le Développement (IRD), Météo-France Direction Interrégionale Sud-Est (DIRSE), Météo-France, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Paul-Valéry - Montpellier 3 (UPVM)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École Pratique des Hautes Études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)

Subjects
[SDV] Life Sciences [q-bio], [SDE] Environmental Sciences, [SDV]Life Sciences [q-bio], CYCLES BIOGEOCHIMIQUES, [SDE]Environmental Sciences, ComputingMilieux_MISCELLANEOUS, ECOLOGIE
Abstract

International audience

Published
2008

50. Dense water formation in the Gulf of Lions shelf: Impact of atmospheric interannual variability and climate change

Author

Patrick Marsaleix, Florence Sevault, Marine Herrmann, Michel Déqué, Samuel Somot, Claude Estournel, Laboratoire d'aérologie (LA), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire d'aérologie (LAERO), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, Climate change, Stratification (water), Atmospheric model, Aquatic Science, Oceanography, 01 natural sciences, Deep sea, Interannual variability, Water column, Mediterranean sea, Dense water cascading, 14. Life underwater, Surface layer, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], geography, geography.geographical_feature_category, Continental shelf, 010604 marine biology & hydrobiology, Modeling, Geology, 13. Climate action, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Environmental science
Abstract

accepted; International audience; Dense water formed over the continental shelf and cascading down the slope is responsible for shelf-slope exchanges in many parts of the world ocean, and transports large amounts of sediment and organic matter into the deep ocean. Here we perform numerical modeling experiments to investigate the impact of atmospheric interannual variability and climate change on dense water formation over the Gulf of Lions shelf, in the Northwestern Mediterranean Sea. Results obtained for a 140 years eddy-permitting simulation (1960–2100) performed over the whole Mediterranean Sea under IPCC A2 scenario forcings are used to force a regional eddy-resolving model of the Northwestern Mediterranean Sea.For the years selected in the present period, the quantity of dense water formed over and exported from the shelf is well correlated with atmospheric conditions, and dense water cascading is in agreement with available observations. During years colder than the average, most of the dense water formed over the shelf sinks into the deep ocean by cascading. During warmer years, dense water is mainly consumed by mixing with lighter surrounding water, and only a small quantity escapes the shelf, flowing along the coast without sinking.For the years selected in the future period, dense water formation over the shelf is strongly reduced, due to the stronger stratification of the water column. Most of the dense water formed is consumed over the shelf by mixing. A very small part escapes the shelf, flowing mainly in the surface layer: cascading practically disappears.The extrapolation of the results obtained for the selected years to the whole present and future periods suggests that volumes of dense water annually formed on the shelf, exported and cascading from the shelf are reduced by, respectively, 50%, 90% and 90% between the 20th century and the end of the 21st century. Uncertainties regarding our results are evaluated: the uncertainty due to the choice of the atmospheric forcing model is the most important, however, a decrease of cascading of at least 60% for the end of the 21st century compared to the present climate is obtained for every atmospheric model examined.

Published
2008
Full Text
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