Search

Your search keyword '"Chris M. Brierley"' showing total 19 results
Start Over Author "Chris M. Brierley"
19 results on '"Chris M. Brierley"'

1. No Consistent Simulated Trends in the Atlantic Meridional Overturning Circulation for the Past 6,000 Years

Author

Zhiyi Jiang, Chris M. Brierley, Jürgen Bader, Pascale Braconnot, Michael Erb, Peter O. Hopcroft, Dabang Jiang, Johann Jungclaus, Vyacheslav Khon, Gerrit Lohmann, Olivier Marti, Matthew B. Osman, Bette Otto‐Bliesner, Birgit Schneider, Xiaoxu Shi, David J. R. Thornalley, Zhiping Tian, and Qiong Zhang

Subjects
AMOC, Holocene, Geophysics. Cosmic physics, QC801-809
Abstract

Abstract The Atlantic Meridional Overturning Circulation (AMOC) is a key feature of the North Atlantic with global ocean impacts. The AMOC's response to past changes in forcings during the Holocene provides important context for the coming centuries. Here, we investigate AMOC trends using an emerging set of transient simulations using multiple global climate models for the past 6,000 years. Although some models show changes, no consistent trend in overall AMOC strength during the mid‐to‐late Holocene emerges from the ensemble. We interpret this result to suggest no overall change in AMOC, which fits with our assessment of available proxy reconstructions. The decadal variability of the AMOC does not change in ensemble during the mid‐ and late‐Holocene. There are interesting AMOC changes seen in the early Holocene, but their nature depends a lot on which inputs are used to drive the experiment.

Published
2023
Full Text
View/download PDF

2. Objective determination of the extratropical transition of tropical cyclones in the Northern Hemisphere

Author

Joshua Studholme, Kevin I. Hodges, and Chris M. Brierley

Subjects
tropical cyclones, extratropical transition, operational analyses, clustering, Oceanography, GC1-1581, Meteorology. Climatology, QC851-999
Abstract

Extratropical transition (ET) has eluded objective identification since the realisation of its existence in the 1970s. Recent advances in numerical, computational models have provided data of higher resolution than previously available. In conjunction with this, an objective characterisation of the structure of a storm has now become widely accepted in the literature. Here we present a method of combining these two advances to provide an objective method for defining ET. The approach involves applying K-means clustering to isolate different life-cycle stages of cyclones and then analysing the progression through these stages. This methodology is then tested by applying it to five recent years from the European Centre of Medium-Range Weather Forecasting operational analyses. It is found that this method is able to determine the general characteristics for ET in the Northern Hemisphere. Between 2008 and 2012, 54% (±7, 32 of 59) of Northern Hemisphere tropical storms are estimated to undergo ET. There is great variability across basins and time of year. To fully capture all the instances of ET is necessary to introduce and characterise multiple pathways through transition. Only one of the three transition types needed has been previously well-studied. A brief description of the alternate types of transitions is given, along with illustrative storms, to assist with further study.

Published
2015
Full Text
View/download PDF

3. Large-scale features of Last Interglacial climate: results from evaluating the lig127k simulations for the Coupled Model Intercomparison Project (CMIP6)–Paleoclimate Modeling Intercomparison Project (PMIP4)

Author

Bette L. Otto-Bliesner, Esther C. Brady, Anni Zhao, Chris M. Brierley, Yarrow Axford, Emilie Capron, Aline Govin, Jeremy S. Hoffman, Elizabeth Isaacs, Masa Kageyama, Paolo Scussolini, Polychronis C. Tzedakis, Charles J. R.Williams, Eric Wolff, Ayako Abe-Ouchi, Pascale Braconnot, Silvana Ramos Buarque, Jian Cao, Anne de Vernal, Maria Vittoria Guarino, Chuncheng Guo, Allegra N. Legrande, Gerrit Lohmann, Katrin J. Meissner, Laurie Menviel, Polina A. Morozova, Kerim H. Nisancioglu, Ryouta O’ishi, David Salas y Mélia, Xiaoxu Shi, Marie Sicard, Louise Sime, Christian Stepanek, Robert Tomas, Evgeny Volodin, Nicholas K. H. Yeung, Qiong Zhang, Zhongshi Zhang, and Weipeng Zheng

Subjects
Meteorology And Climatology
Abstract

The modeling of paleoclimate, using physically based tools, is increasingly seen as a strong out-of-sample test of the models that are used for the projection of future climate changes. New to the Coupled Model Intercomparison Project (CMIP6) is the Tier 1 Last Interglacial experiment for 127 000 years ago (lig127k), designed to address the climate responses to stronger orbital forcing than the midHolocene experiment, using the same state-of-the-art models as for the future and following a common experimental protocol. Here we present a first analysis of a multi-model ensemble of 17 climate models, all of which have completed the CMIP6 DECK (Diagnostic, Evaluation and Characterization of Klima) experiments. The equilibrium climate sensitivity (ECS) of these models varies from 1.8 to 5.6°C. The seasonal character of the insolation anomalies results in strong summer warming over the Northern Hemisphere continents in the lig127k ensemble as compared to the CMIP6 piControl and much-reduced minimum sea ice in the Arctic. The multi-model results indicate enhanced summer monsoonal precipitation in the Northern Hemisphere and reductions in the Southern Hemisphere. These responses are greater in the lig127k than the CMIP6 midHolocene simulations as expected from the larger insolation anomalies at 127 than 6 ka. New synthesis for surface temperature and precipitation, targeted for 127 ka, have been developed for comparison to the multi-model ensemble. The lig127k model ensemble and data reconstructions are in good agreement for summer temperature anomalies over Canada, Scandinavia, and the North Atlantic and for precipitation over the Northern Hemisphere continents. The model–data comparisons and mismatches point to further study of the sensitivity of the simulations to uncertainties in the boundary conditions and of the uncertainties and sparse coverage in current proxy reconstructions. The CMIP6–Paleoclimate Modeling Intercomparison Project (PMIP4) lig127k simulations, in combination with the proxy record, improve our confidence in future projections of monsoons, surface temperature, and Arctic sea ice, thus providing a key target for model evaluation and optimization.

Published
2021
Full Text
View/download PDF

4. Evaluation of Arctic Warming in Mid-Pliocene Climate Simulations

Author

Wesley de Nooijer, Qiong Zhang, Qiang Zhang, Xiangyu Li, Chuncheng Guo, Kerim H Nisancioglu, Alan M Haywood, Julia C Tindall, Stephen J Hunter, Harry J Dowsett, Christian Stepanek, Gerrit Lohmann, Bette L Otto-Bliesner, Ran Feng, Linda E Sohl, Mark A Chandler, Ning Tan, Camille Contoux, Gilles Ramstein, Michiel L J Baatsen, Anna S von der Heydt, Deepak Chandan, W Richard Peltier, Ayako Abe-Ouchi, Wing-Le Chan, Youichi Kamae, and Chris M Brierley

Subjects
Meteorology And Climatology
Abstract

Palaeoclimate simulations improve our understanding of the climate, inform us about the performance of climate models in a different climate scenario, and help to identify robust features of the climate system. Here, we analyse Arctic warming in an ensemble of 16 simulations of the mid-Pliocene Warm Period (mPWP), derived from the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2). The PlioMIP2 ensemble simulates Arctic (60–90∘ N) annual mean surface air temperature (SAT) increases of 3.7 to 11.6 ∘C compared to the pre-industrial period, with a multi-model mean (MMM) increase of 7.2 ∘C. The Arctic warming amplification ratio relative to global SAT anomalies in the ensemble ranges from 1.8 to 3.1 (MMM is 2.3). Sea ice extent anomalies range from −3.0 to −10.4×106 km2, with a MMM anomaly of −5.6×106 km2, which constitutes a decrease of 53 % compared to the pre-industrial period. The majority (11 out of 16) of models simulate summer sea-ice-free conditions (≤1×106 km2) in their mPWP simulation. The ensemble tends to underestimate SAT in the Arctic when compared to available reconstructions, although the degree of underestimation varies strongly between the simulations. The simulations with the highest Arctic SAT anomalies tend to match the proxy dataset in its current form better. The ensemble shows some agreement with reconstructions of sea ice, particularly with regard to seasonal sea ice. Large uncertainties limit the confidence that can be placed in the findings and the compatibility of the different proxy datasets. We show that while reducing uncertainties in the reconstructions could decrease the SAT data–model discord substantially, further improvements are likely to be found in enhanced boundary conditions or model physics. Lastly, we compare the Arctic warming in the mPWP to projections of future Arctic warming and find that the PlioMIP2 ensemble simulates greater Arctic amplification than CMIP5 future climate simulations and an increase instead of a decrease in Atlantic Meridional Overturning Circulation (AMOC) strength compared to pre-industrial period. The results highlight the importance of slow feedbacks in equilibrium climate simulations, and that caution must be taken when using simulations of the mPWP as an analogue for future climate change.

Published
2020
Full Text
View/download PDF

5. Large-scale features and evaluation of the PMIP4-CMIP6 midHolocene simulations

Author

Chris M. Brierley, Anni Zhao, Sandy P. Harrison, Pascale Braconnot, Charles J. R. Williams, David J. R. Thornalley, Xiaoxu Shi, Jean-Yves Peterschmitt, Rumi Ohgaito, Darrell S. Kaufman, Masa Kageyama, Julia C. Hargreaves, Michael P. Erb, Julien Emile-Geay, Roberta D Agostino, Deepak Chandan, Matthieu Carré, Partrick J. Bartlein, Weipeng Zheng, Zhongshi Zhang, Qiong Zhang, Hu Yang, Evgeny M. Volodin, Robert A. Tomas, Cody Routson, W. Richard Peltier, Bette Otto-Bliesner, Polina A. Morozova, Nicholas P. McKay, Gerrit Lohmann, Allegra N. Legrande, Chuncheng Guo, Jian Cao, Esther Brady, James D. Annan, and Ayako Abe-Ouchi7

Subjects
Meteorology And Climatology
Abstract

The mid-Holocene (6000 years ago) is a standard time period for the evaluation of the simulated response of global climate models using palaeoclimate reconstructions. The latest mid-Holocene simulations are a palaeoclimate entry card for the Palaeoclimate Model Intercomparison Project (PMIP4) component of the current phase of the Coupled Model Intercomparison Project (CMIP6) – hereafter referred to as PMIP4-CMIP6. Here we provide an initial analysis and evaluation of the results of the experiment for the mid-Holocene. We show that state-of-the-art models produce climate changes that are broadly consistent with theory and observations, including increased summer warming of the Northern Hemisphere and associated shifts in tropical rainfall. Many features of the PMIP4-CMIP6 simulations were present in the previous generation (PMIP3-CMIP5) of simulations. The PMIP4-CMIP6 ensemble for the mid-Holocene has a global mean temperature change of −0.3 K, which is −0.2 K cooler than the PMIP3-CMIP5 simulations predominantly as a result of the prescription of realistic greenhouse gas concentrations in PMIP4-CMIP6. Biases in the magnitude and the sign of regional responses identified in PMIP3-CMIP5, such as the amplification of the northern African monsoon, precipitation changes over Europe, and simulated aridity in mid-Eurasia, are still present in the PMIP4-CMIP6 simulations. Despite these issues, PMIP4-CMIP6 and the mid-Holocene provide an opportunity both for quantitative evaluation and derivation of emergent constraints on the hydrological cycle, feedback strength, and potentially climate sensitivity.

Published
2020
Full Text
View/download PDF

6. Comparison of past and future simulations of ENSO in CMIP5/PMIP3 and CMIP6/PMIP4 models

Author

Josephine R. Brown, Chris M. Brierley, Soon-Il An, Maria-Vittoria Guarino, Samantha Stevenson, Charles J. R. Williams, Qiong Zhang, Anni Zhao, Ayako Abe-Ouchi, Pascale Braconnot, Esther C. Brady, Deepak Chandan, Roberta D’Agostino, Chuncheng Guo, Allegra N. Legrande, Gerrit Lohmann, Polina A. Morozova, Rumi Ohgaito, Ryouta O’ishi, Bette L. Otto-Bliesner, W. Richard Peltier, Xiaoxu Shi, Louise Sime, Evgeny M. Volodin, Zhongshi Zhang, and Weipeng Zheng

Subjects
Meteorology And Climatology
Abstract

El Niño–Southern Oscillation (ENSO) is the strongest mode of interannual climate variability in the current climate, influencing ecosystems, agriculture, and weather systems across the globe, but future projections of ENSO frequency and amplitude remain highly uncertain. A comparison of changes in ENSO in a range of past and future climate simulations can provide insights into the sensitivity of ENSO to changes in the mean state, including changes in the seasonality of incoming solar radiation, global average temperatures, and spatial patterns of sea surface temperatures. As a comprehensive set of coupled model simulations is now available for both palaeoclimate time slices (the Last Glacial Maximum, mid-Holocene, and last interglacial) and idealised future warming scenarios (1 % per year CO2 increase, abrupt four-time CO2 increase), this allows a detailed evaluation of ENSO changes in this wide range of climates. Such a comparison can assist in constraining uncertainty in future projections, providing insights into model agreement and the sensitivity of ENSO to a range of factors. The majority of models simulate a consistent weakening of ENSO activity in the last interglacial and mid-Holocene experiments, and there is an ensemble mean reduction of variability in the western equatorial Pacific in the Last Glacial Maximum experiments. Changes in global temperature produce a weaker precipitation response to ENSO in the cold Last Glacial Maximum experiments and an enhanced precipitation response to ENSO in the warm increased CO2 experiments. No consistent relationship between changes in ENSO amplitude and annual cycle was identified across experiments.

Published
2020
Full Text
View/download PDF

7. Analysing the PMIP4-CMIP6 collection: a workflow and tool (pmip_p2fvar_analyzer v1)

Author

Anni Zhao, Chris M. Brierley, Zhiyi Jiang, Rachel Eyles, Damián Oyarzún, and Jose Gomez-Dans

Subjects
General Medicine
Abstract

Experiment outputs are now available from the Coupled Model Intercomparison Project's sixth phase (CMIP6) and the past climate experiments defined in the Palaeoclimate Modelling Intercomparison Project's fourth phase (PMIP4). All of this output is freely available from the Earth System Grid Federation (ESGF). Yet there is overhead in analysing this resource that may prove complicated or prohibitive. Here we document the steps taken by ourselves to produce ensemble analyses covering past and future simulations. We outline the strategy used to curate, adjust the monthly calendar aggregation and process the information downloaded from the ESGF. The results of these steps were used to perform analysis for several of the initial publications arising from PMIP4. We provide post-processed fields for each simulation, such as climatologies and common measures of variability. Example scripts used to visualise and analyse these fields are provided for several important case studies.

Published
2022
Full Text
View/download PDF

8. No changes in overall AMOC strength in interglacial PMIP4 timeslices

Author

Zhiyi Jiang, Chris M. Brierley, David J. R. Thornalley, and Sophie Sax

Abstract

The Atlantic Meridional Overturning Circulation (AMOC) is a key mechanism of poleward heat transport and an important part of the global climate system. How it responded to past changes in forcing, such as experienced during Quaternary interglacials, is an intriguing and open question. Previous modelling studies suggest an enhanced AMOC in the mid-Holocene compared to the pre-industrial period. In earlier simulations from the Palaeoclimate Modelling Intercomparison Project (PMIP), this arose from feedbacks between sea ice and AMOC changes, which were dependent on resolution. Here we present an initial analysis of the recently available PMIP4 simulations. The ensemble mean of the PMIP4 models shows the strength of the AMOC does not markedly change between the midHolocene and piControl experiments or between the lig127k and piControl experiments. Therefore, it appears orbital forcing itself does not alter the overall AMOC. We further investigate the coherency of the forced response in AMOC across the two interglacials, along with the strength of the signal, using eight PMIP4 models which performed both interglacial experiments. Only 2 models show a stronger change with the stronger forcing, but those models disagree on the direction of the change. We propose that the strong signals in these 2 models are caused by a combination of forcing and the internal variability. After investigating the AMOC changes in the interglacials, we further explored the impact of AMOC on the climate system, especially on the changes in the simulated surface temperature and precipitation. After identifying the AMOC’s fingerprint on the surface temperature and rainfall, we demonstrate that only a small percentage of the simulated surface climate changes can be attributed to the AMOC. Proxy records during the two interglacial periods paint a similar picture of minimal changes, which fits nicely with the simulated results. Although the overall AMOC strength shows minimal changes, future work is required to explore whether this occurs through compensating variations in the different components of AMOC (such as Iceland-Scotland overflow water). This lines of evidence caution against interpreting reconstructions of past interglacial climate as being driven by AMOC, outside of abrupt events.

Published
2022

9. Calendar effects on surface air temperature and precipitation based on model-ensemble equilibrium and transient simulations from PMIP4 and PACMEDY

Author

Xiaoxu Shi, Martin Werner, Carolin Krug, Chris M. Brierley, Anni Zhao, Endurance Igbinosa, Pascale Braconnot, Esther Brady, Jian Cao, Roberta D'Agostino, Johann Jungclaus, Xingxing Liu, Bette Otto-Bliesner, Dmitry Sidorenko, Robert Tomas, Evgeny M. Volodin, Hu Yang, Qiong Zhang, Weipeng Zheng, Gerrit Lohmann, 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), 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)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), and This research has been supported by the German Federal Ministry of Education and Science (BMBF) PalMod II WP 3.3 (grant no. 01LP1924B) and the PAlaeo-Constraints on Monsoon Evolution and Dynamics (PACMEDY) Belmont Forum project (grant no. 01LP1607A). Xingxing Liu is funded by the open fund of State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, CAS (grant no. SKLLQG1920) and the National Science Foundation for Young Scientists of China (grant no. 41807425). Roberta D’Agostino is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy – EXC 2037 Climate, Climatic Change, and Society (CLICCS) – Cluster of Excellence Hamburg, A4 African and Asian Monsoon Margins (grant no. 390683824). Qiong Zhang is funded by the Swedish Research Council (Vetenskapsrådet, grant nos. 2013-06476 and 2017-04232). Esther Brady and Bette Otto-Bliesner are supported by the National Center for Atmospheric Research, which is a major facility sponsored by the National Science Foundation underCooperative Agreement (grant no. 1852977).

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Global and Planetary Change, Stratigraphy, Paleontology, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

Numerical modelling enables a comprehensive understanding not only of the Earth's system today, but also of the past. To date, a significant amount of time and effort has been devoted to paleoclimate modeling and analysis, which involves the latest and most advanced Paleoclimate Modelling Intercomparison Project phase 4 (PMIP4). The definition of seasonality, which is influenced by slow variations in the Earth's orbital parameters, plays a key role in determining the calculated seasonal cycle of the climate. In contrast to the classical calendar used today, where the lengths of the months and seasons are fixed, the angular calendar calculates the lengths of the months and seasons according to a fixed number of degrees along the Earth's orbit. When comparing simulation results for different time intervals, it is essential to account for the angular calendar to ensure that the data for comparison is from the same position along the Earth's orbit. Most models use the classical "fixed-length" calendar, which can lead to strong distortions of the monthly and seasonal values, especially for the climate of the past. Here, by analyzing daily outputs from multiple PMIP4 model simulations, we examine calendar effects on surface air temperature and precipitation under mid-Holocene, last interglacial, and pre-industrial climate conditions. We conclude that: (a) The largest cooling bias occurs in autumn when the classical calendar is applied for the mid-Holocene and last interglacial. (b) The sign of the temperature anomalies between the Last Interglacial and pre-industrial in boreal autumn can be reversed after the switch from classical to angular calendar, particularly over the Northern Hemisphere continents. (c) Precipitation over West Africa is overestimated in boreal summer and underestimated in boreal autumn when the "fixed-length" seasonal cycle is applied. (d) Finally, correcting the calendar based on the monthly model results can reduce the biases to a large extent, but not completely eliminate them. In addition, we examine the calendar effects in 3 transient simulations for 6–0 ka by AWI-ESM, MPI-ESM, and IPSL. We find significant discrepancies between adjusted and unadjusted temperature values over ice-free continents for both hemispheres in boreal autumn. While for other seasons the deviations are relatively small. A drying bias can be found in the summer monsoon precipitation in Africa (in the "fixed-length" calendar), whereby the magnitude of bias becomes smaller over time. Overall, our study underlines the importance of the application of calendar transformation in the analysis of climate simulations. Neglecting the calendar effects could lead to a profound artificial distortion of the calculated seasonal cycle of surface air temperature and precipitation. One important fact to be noted here is that the discrepancy in seasonality under different calendars is an analysis bias and is highly depends on the choice of the reference position/date (usually the vernal equinox, which is set to 31th March) on the Earth's ellipse around the sun. Different model groups may apply different reference dates, so ensuring a consistent reference date and seasonal definition is key when we compare results across multiple models.

Published
2022
Full Text
View/download PDF

10. Multi-centennial Holocene climate variability in proxy records and transient model simulations

Author

Thomas Gravgaard Askjær, Qiong Zhang, Frederik Schenk, Fredrik Charpentier Ljungqvist, Zhengyao Lu, Chris M. Brierley, Peter O. Hopcroft, Johann Jungclaus, Xiaoxu Shi, Gerrit Lohmann, Weiyi Sun, Jian Liu, Pascale Braconnot, Bette L. Otto-Bliesner, Zhipeng Wu, Qiuzhen Yin, Yibo Kang, Haijun Yang, 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), and UCL - SST/ELI/ELIC - Earth & Climate

Subjects
Archeology, Global and Planetary Change, History, Model-proxy comparison, Multi-centennial climate variability, Geology, Spectral analysis, Historia, Environmental Sciences related to Agriculture and Land-use, Holocene transient simulations, [SDU]Sciences of the Universe [physics], [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Miljö- och naturvårdsvetenskap, Ecology, Evolution, Behavior and Systematics, Paleoclimate proxy records
Abstract

Highlights: • Multi-centennial oscillation with 100–200 years periods is evident in proxy data and model simulations during the Holocene. • Multi-centennial oscillation is a global signal and is more significant in the Northern Hemisphere high latitudes. • None of the external forcings is found to be the sole driver of the multi-centennial variability. • It indicates the multi-centennial oscillation may be due to potential internal drivers and essential feedbacks. Abstract: Variability on centennial to multi-centennial timescales is mentioned as a feature in reconstructions of the Holocene climate. As more long transient model simulations with complex climate models become available and efforts have been made to compile large proxy databases, there is now a unique opportunity to study multi-centennial variability with greater detail and a large amount of data than earlier. This paper presents a spectral analysis of transient Holocene simulations from 9 models and 120 proxy records to find the common signals related to oscillation periods and geographic dependencies and discuss the implications for the potential driving mechanisms. Multi-centennial variability is significant in most proxy records, with the dominant oscillation periods around 120–130 years and an average of 240 years. Spectra of model-based global mean temperature (GMT) agree well with proxy evidence with significant multi-centennial variability in all simulations with the dominant oscillation periods around 120–150 years. It indicates a comparatively good agreement between model and proxy data. A lack of latitudinal dependencies in terms of oscillation period is found in both the model and proxy data. However, all model simulations have the highest spectral density distributed over the Northern hemisphere high latitudes, which could indicate a particular variability sensitivity or potential driving mechanisms in this region. Five models also have differentiated forcings simulations with various combinations of forcing agents. Significant multi-centennial variability with oscillation periods between 100 and 200 years is found in all forcing scenarios, including those with only orbital forcing. The different forcings induce some variability in the system. Yet, none appear to be the predominant driver based on the spectral analysis. Solar irradiance has long been hypothesized to be a primary driver of multi-centennial variability. However, all the simulations without this forcing have shown significant multi-centennial variability. The results then indicate that internal mechanisms operate on multi-centennial timescales, and the North Atlantic-Arctic is a region of interest for this aspect.

Published
2022
Full Text
View/download PDF

11. Severe Drought Conditions in Northern East Asia During the Early Pliocene Caused by Weakened Pacific Meridional Temperature Gradient

Author

Yanhong Zheng, Alexey V. Fedorov, Natalie J. Burls, Rui Zhang, Chris M. Brierley, Zhengkun Fang, Xuefeng Yu, Feng Xian, Hongxuan Lu, State Key Laboratory of Continental Tectonics and Dynamics [Beijing], Institute of Geology [Beijing], Chinese Academy of Geological Sciences [Beijing] (CAGS), Ministry of Land and Resources (MLR)-Ministry of Land and Resources (MLR)-Chinese Academy of Geological Sciences [Beijing] (CAGS), Ministry of Land and Resources (MLR)-Ministry of Land and Resources (MLR), State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences [Xi’an], Océan et variabilité du climat (VARCLIM), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-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)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-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)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), 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)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Department of Earth and Planetary Sciences [New Haven], Yale University [New Haven], George Mason University [Fairfax], Department of Geography, University College of London [London] (UCL), and ANR-18-MPGA-0001,ARCHANGE,Changement climatique et Arctique et circulation océanique globale(2018)

Subjects
drought conditions, Geophysics, Asian summer monsoon, [SDU]Sciences of the Universe [physics], [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, GDGTs, General Earth and Planetary Sciences, meridional SST gradient, early pliocene
Abstract

International audience; The evolution of hydroclimate in East Asia during the Pliocene—a potential analog of the future greenhouse climate—remains highly uncertain. Here we reconstruct changes in the hydroclimate of Northern China during this epoch. Our results reveal previously undocumented severe drought conditions that persisted through the early Pliocene with a significantly greater magnitude than suggested by other records. Using a broad hierarchy of climate simulations, we find that reduction in the Pacific meridional sea surface temperature (SST) gradient has particularly strong impacts on precipitation over Northern China, which suggests its key role in maintaining drought conditions during the early Pliocene. The weaker Pacific meridional SST gradient causes the weakening of the East Asian summer monsoon precipitation over this region via a reduction of atmospheric northward moisture transport from the ocean, which enhances aridity inland. Our results highlight the fundamental control of the tropical ocean on the extra-tropical hydrological cycle.

Published
2022
Full Text
View/download PDF

12. Supplementary material to 'Calendar effects on surface air temperature and precipitation based on model-ensemble equilibrium and transient simulations from PMIP4 and PACMEDY'

Author

Xiaoxu Shi, Martin Werner, Carolin Krug, Chris M. Brierley, Anni Zhao, Endurance Igbinosa, Pascale Braconnot, Esther Brady, Jian Cao, Roberta D'Agostino, Johann Jungclaus, Xingxing Liu, Bette Otto-Bliesner, Dmitry Sidorenko, Robert Tomas, Evgeny M. Volodin, Hu Yang, Qiong Zhang, Weipeng Zheng, and Gerrit Lohmann

Published
2021
Full Text
View/download PDF

13. Supplementary material to 'Evaluation of Arctic warming in mid-Pliocene climate simulations'

Author

Wesley de Nooijer, Qiong Zhang, Qiang Li, Qiang Zhang, Xiangyu Li, Zhongshi Zhang, Chuncheng Guo, Kerim H. Nisancioglu, Alan M. Haywood, Julia C. Tindall, Stephen J. Hunter, Harry J. Dowsett, Christian Stepanek, Gerrit Lohmann, Bette L. Otto-Bliesner, Ran Feng, Linda E. Sohl, Ning Tan, Camille Contoux, Gilles Ramstein, Michiel L. J. Baatsen, Anna S. von der Heydt, Deepak Chandan, W. Richard Peltier, Ayako Abe-Ouchi, Wing-Le Chan, Youichi Kamae, and Chris M. Brierley

Published
2020
Full Text
View/download PDF

14. Supplementary material to 'Comparison of past and future simulations of ENSO in CMIP5/PMIP3 and CMIP6/PMIP4 models'

Author

Josephine R. Brown, Chris M. Brierley, Soon-Il An, Maria-Vittoria Guarino, Samantha Stevenson, Charles J. R. Williams, Qiong Zhang, Anni Zhao, Pascale Braconnot, Esther C. Brady, Deepak Chandan, Roberta D'Agostino, Chuncheng Guo, Allegra N. LeGrande, Gerrit Lohmann, Polina A. Morozova, Rumi Ohgaito, Ryouta O'ishi, Bette Otto-Bliesner, W. Richard Peltier, Xiaoxu Shi, Louise Sime, Evgeny M. Volodin, Zhongshi Zhang, and Weipeng Zheng

Published
2020
Full Text
View/download PDF

17. Supplementary material to 'Large-scale features and evaluation of the PMIP4-CMIP6 midHolocene simulations'

Author

Chris M. Brierley, Anni Zhao, Sandy P. Harrison, Pascale Braconnot, Charles J. R. Williams, David J. R. Thornalley, Xiaoxu Shi, Jean-Yves Peterschmitt, Rumi Ohgaito, Darrell S. Kaufman, Masa Kageyama, Julia C. Hargreaves, Micheal P. Erb, Julien Emile-Geay, Roberta D'Agostino, Deepak Chandan, Matthieu Carré, Patrick Bartlein, Weipeng Zheng, Zhongshi Zhang, Qiong Zhang, Hu Yang, Evgeny M. Volodin, Robert A. Tomas, Cody Routson, W. Richard Peltier, Bette Otto-Bliesner, Polina A. Morozova, Nicholas P. McKay, Gerrit Lohmann, Allegra N. Legrande, Chuncheng Guo, Jian Cao, Esther Brady, James D. Annan, and Ayako Abe-Ouchi

Published
2020
Full Text
View/download PDF

18. Large-scale features of Last Interglacial climate: Results from evaluating the lig127k simulations for the Coupled Model Intercomparison Project (CMIP6)-Paleoclimate Modeling Intercomparison Project (PMIP4)

Author

Yarrow Axford, Ayako Abe-Ouchi, Maria-Vittoria Guarino, Qiong Zhang, Elizabeth B. Isaacs, Bette L. Otto-Bliesner, Robert A. Tomas, Jeremy S. Hoffman, Zhongshi Zhang, Anne de Vernal, Nicholas K. H. Yeung, Masa Kageyama, Weipeng Zheng, Katrin J. Meissner, Christian Stepanek, Jian Cao, Chris Brierley, Gerrit Lohmann, Anni Zhao, Laurie Menviel, David Salas y Mélia, Polina Morozova, Louise C. Sime, Eric W. Wolff, Ryouta O'ishi, Silvana Ramos Buarque, Emilie Capron, Allegra N. LeGrande, Charles Williams, Marie Sicard, Polychronis C Tzedakis, Pascale Braconnot, Evgeny Volodin, Chuncheng Guo, Esther C. Brady, Xaoxu Shi, Paolo Scussolini, Aline Govin, Kerim H. Nisancioglu, 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), Climat et Magnétisme (CLIMAG), 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), Modélisation du climat (CLIM), Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID), National Science Foundation, NSF National Center for Atmospheric Research, NCAR: 1852977 Natural Environment Research Council, NERC: NE/S009736/1 Nederlandse Organisatie voor Wetenschappelijk Onderzoek, NWO: ALWOP.164 Sorbonne Université California Earthquake Authority, CEA Carlsbergfondet École Polytechnique Fédérale de Lausanne, EPFL Royal Society Centre National d’Etudes Spatiales, CNES 742224 European Research Council, ERC NE/P01903X/1, ANR-18-BELM-0001-06 312979 Centre National de la Recherche Scientifique, CNRS RSF Social Finance: 20-17-00190 Natural Environment Research Council, NERC: NE/P013279/1 Vetenskapsrådet, VR Bundesministerium für Bildung und Forschung, BMBF Vetenskapsrådet, VR: 2016-07213, 2013-06476, 2017-04232 Achievement Rewards for College Scientists Foundation, ARCS: JPMXD1300000000 JPMXD1420318865 Australian Research Council, ARC: FT180100606 2016YFC1401401 Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, AWI Japan Society for the Promotion of Science, KAKEN: 17H06104 Ministry of Education, Culture, Sports, Science and Technology, Monbusho: 17H06323 Chinese Academy of Sciences, CAS: XDB42000000, XDA19060102 Japan Agency for Marine-Earth Science and Technology, JAMSTEC: 0148-2019-0009 National Natural Science Foundation of China, NSFC: 91958201and 41376002 National Science Foundation, NSF Chinese Academy of Sciences, CAS Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, SNF Akademie der Naturwissenschaften, SCNAT National Science Foundation, NSF: 1852977 National Center for Atmospheric Research, NCAR, Acknowledgements. Bette L. Otto-Bliesner, Esther C. Brady and Robert Tomas acknowledge the CESM project, which is supported primarily by the National Science Foundation (NSF). This material is based upon work supported by the National Center for Atmospheric Research (NCAR), which is a major facility sponsored by the NSF under Cooperative Agreement No. 1852977. Computing and data storage resources, including the Cheyenne supercomputer (https://doi.org/10.5065/D6RX99HX), were provided by the Computational and Information Systems Laboratory (CISL) at NCAR. Chris M. Brierley acknowledges the financial support of the Natural Environment Research Council through grant NE/S009736/1. Anni Zhao and Chris M. Brierley would like to thank Rachel Eyles for her sterling work curating the local replica of the PMIP archive at UCL., Charles J. R. Williams acknowledges the financial support of the UK Natural Environment Research Council-funded SWEET project (Super-Warm Early Eocene Temperatures), research grant NE/P01903X/1, and the financial support of the Belmont-funded PACMEDY (PAlaeo-Constraints on Monsoon Evolution and Dynamics) project. Aline Govin acknowledges the support of the French national program LEFE/INSU (CircLIG project) and of the Belmont-funded ACCEDE project (ANR-18-BELM-0001-06). Eric Wolff has received funding from the European Research Council under the Horizon 2020 program research and innovation program (grant agreement no. 742224, WACSWAIN). Eric Wolff is also funded by a Royal Society Professorship. Paolo Scussolini acknowledges funding from the NWO (Nederlandse Organisatie voor Wetenschappelijk Onderzoek) under grant ALWOP.164. Emilie Capron acknowledges financial support from the ChronoCli-mate project, funded by the Carlsberg Foundation. Pascale Bra-connot and Masa Kageyama acknowledge the HPC resources of TGCC allocated to the IPSL CMIP6 project by GENCI (Grand Equipment National de Calcul Intensif) under the allocations 2016-A0030107732, 2017-R0040110492, and 2018-R0040110492 (project gencmip6). This work was undertaken in the framework of the LABEX L-IPSL and the IPSL Climate Graduate School, under the 'Investissements d’avenir' program with the reference ANR-11-IDEX-0004-17-EURE-0006. This study benefited from the ES-PRI (Ensemble de Services Pour la Recherche à l’IPSL) computing and data center (https://mesocentre.ipsl.fr, last access: 22 December 2020), which is supported by CNRS, Sorbonne Université, École Polytechnique, and CNES and through national and international projects, including the EU-FP7 Infrastructure project IS-ENES2 (grant no. 312979). Marie Sicard is funded by a scholarship from CEA and 'Convention des Services Climatiques' from IPSL., Laurie Menviel acknowledges support from the Australian Research Council FT180100606. The ACCESS-ESM 1.5 experiments were performed on Raijin at the NCI National Facility at the Australian National University, through awards under the National Computational Merit Allocation Scheme, the Intersect allocation scheme, and the UNSW HPC at NCI Scheme. Qiong Zhang acknowledges the support from the Swedish Research Council (Vetenskapsrådet, grant nos. 2013-06476 and 2017-04232). The EC-Earth simulations are performed on ECMWF’s computing and archive facilities and on resources provided by the Swedish National Infrastructure for Computing (SNIC) at the National Supercomputer Centre (NSC) partially funded by the Swedish Research Council through grant agreement no. 2016-07213. Weipeng Zheng acknowledges the financial support from National Key R&D Program for Developing Basic Sciences (grant no. 2016YFC1401401), the Strategic Priority Research Program of Chinese Academy of Sciences (grant nos. XDA19060102 and XDB42000000) and the National Natural Science Foundation of China (grant nos. 91958201and 41376002), and the technical support from the National Key Scientific and Technological Infrastructure project 'Earth System Science Numerical Simulator Facility' (EarthLab). Maria Vittoria Guarino and Louise Sime acknowledge the financial support of the NERC research grant NE/P013279/1. Silvana Ramos Buarque and David Salas y Mélia acknowledge Météo-France/DSI for providing computing and data storage resources. Xiaoxu Shi and Christian Stepanek acknowledge computing and data storage resources for the generation of the AWI-ESM-1/AWI-ESM-2 and MPI-ESM-1-2 simulations of Deutsches Klimarechenzentrum (DKRZ) granted by its Scientific Steering Committee (WLA) under project ID ba1066. The Max Planck Institute for Meteorology in Hamburg is acknowledged for development and provision of the MPI-ESM as well as the ECHAM6/JSBACH, which provides the atmosphere and land surface component of AWI-ESM. Gerrit Lohmann acknowledges funding via the Alfred Wegener Institute’s research program PACES2. Christian Stepanek acknowledges funding by the Helmholtz Climate Initiative REKLIM and the Alfred Wegener Institute’s research program PACES2. Xiaoxu Shi acknowledges financial support through the BMBF funded PACMEDY and PalMOD initiatives. Ayako Abe-Ouchi and Ryouta O’ishi acknowledge the financial support from Arctic Challenge for Sustainability (ArCS) Project (grant JPMXD1300000000), Arctic Challenge for Sustainability II (ArCS II) Project (grant no. JPMXD1420318865), JSPS KAKENHI grant 17H06104 and MEXT KAKENHI grant 17H06323, and the support from JAMSTEC for the use of the Earth Simulator supercomputer. Polina A. Morozova was supported by the state assignment project 0148-2019-0009. Evgeny Volodin was supported by RSF grant 20-17-00190., The authors acknowledge QUIGS (Quaternary Interglacials), a working group of Past Global Changes (PAGES), which in turn received support from the US National Science Foundation, Swiss National Science Foundation, Swiss Academy of Sciences, and the Chinese Academy of Sciences. We are grateful to the World Climate Research Programme (WCRP), which, through its Working Group on Coupled Modelling, coordinated and promoted CMIP6., Financial support. Funding of the publication has been supported by the National Center for Atmospheric Research (NCAR), which is a major facility sponsored by the National Science Foundation under cooperative agreement no. 1852977., Water and Climate Risk, Wolff, Eric [0000-0002-5914-8531], Apollo - University of Cambridge Repository, 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), and 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)

Subjects
IMPACTS, 010506 paleontology, 010504 meteorology & atmospheric sciences, Orbital forcing, sub-01, EXPERIMENTAL-DESIGN, Stratigraphy, lcsh:Environmental protection, 3705 Geology, POLAR AMPLIFICATION, MIDHOLOCENE, 01 natural sciences, lcsh:Environmental pollution, Paleoclimatology, Sea ice, lcsh:TD169-171.8, SDG 14 - Life Below Water, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, TEMPERATURE, AFRICAN MONSOON, lcsh:Environmental sciences, 0105 earth and related environmental sciences, lcsh:GE1-350, 13 Climate Action, Global and Planetary Change, geography, Coupled model intercomparison project, geography.geographical_feature_category, EARTH SYSTEM MODEL, CHRONOLOGY AICC2012, Northern Hemisphere, Paleontology, 37 Earth Sciences, 3709 Physical Geography and Environmental Geoscience, Arctic ice pack, ANTARCTIC ICE, 13. Climate action, Climatology, lcsh:TD172-193.5, 3701 Atmospheric Sciences, Climate sensitivity, Environmental science, Climate model, SENSITIVITY
Abstract

The modeling of paleoclimate, using physically based tools, is increasingly seen as a strong out-of-sample test of the models that are used for the projection of future climate changes. New to the Coupled Model Intercomparison Project (CMIP6) is the Tier 1 Last Interglacial experiment for 127 000 years ago (lig127k), designed to address the climate responses to stronger orbital forcing than the midHolocene experiment, using the same state-of-the-art models as for the future and following a common experimental protocol. Here we present a first analysis of a multi-model ensemble of 17 climate models, all of which have completed the CMIP6 DECK (Diagnostic, Evaluation and Characterization of Klima) experiments. The equilibrium climate sensitivity (ECS) of these models varies from 1.8 to 5.6 ∘C. The seasonal character of the insolation anomalies results in strong summer warming over the Northern Hemisphere continents in the lig127k ensemble as compared to the CMIP6 piControl and much-reduced minimum sea ice in the Arctic. The multi-model results indicate enhanced summer monsoonal precipitation in the Northern Hemisphere and reductions in the Southern Hemisphere. These responses are greater in the lig127k than the CMIP6 midHolocene simulations as expected from the larger insolation anomalies at 127 than 6 ka. New synthesis for surface temperature and precipitation, targeted for 127 ka, have been developed for comparison to the multi-model ensemble. The lig127k model ensemble and data reconstructions are in good agreement for summer temperature anomalies over Canada, Scandinavia, and the North Atlantic and for precipitation over the Northern Hemisphere continents. The model–data comparisons and mismatches point to further study of the sensitivity of the simulations to uncertainties in the boundary conditions and of the uncertainties and sparse coverage in current proxy reconstructions. The CMIP6–Paleoclimate Modeling Intercomparison Project (PMIP4) lig127k simulations, in combination with the proxy record, improve our confidence in future projections of monsoons, surface temperature, and Arctic sea ice, thus providing a key target for model evaluation and optimization.

Published
2021
Full Text
View/download PDF

19. The social cost of carbon dioxide under climate-economy feedbacks and temperature variability

Author

Jarmo S Kikstra, Paul Waidelich, James Rising, Dmitry Yumashev, Chris Hope, and Chris M Brierley

Subjects
climate change, cost–benefit analysis, temperature variability, damage persistence, growth effects, PAGE, Environmental technology. Sanitary engineering, TD1-1066, Environmental sciences, GE1-350, Science, Physics, QC1-999
Abstract

A key statistic describing climate change impacts is the ‘social cost of carbon dioxide’ (SCCO _2 ), the projected cost to society of releasing an additional tonne of CO _2 . Cost-benefit integrated assessment models that estimate the SCCO _2 lack robust representations of climate feedbacks, economy feedbacks, and climate extremes. We compare the PAGE-ICE model with the decade older PAGE09 and find that PAGE-ICE yields SCCO _2 values about two times higher, because of its climate and economic updates. Climate feedbacks only account for a relatively minor increase compared to other updates. Extending PAGE-ICE with economy feedbacks demonstrates a manifold increase in the SCCO _2 resulting from an empirically derived estimate of partially persistent economic damages. Both the economy feedbacks and other increases since PAGE09 are almost entirely due to higher damages in the Global South. Including an estimate of interannual temperature variability increases the width of the SCCO _2 distribution, with particularly strong effects in the tails and a slight increase in the mean SCCO _2 . Our results highlight the large impacts of climate change if future adaptation does not exceed historical trends. Robust quantification of climate-economy feedbacks and climate extremes are demonstrated to be essential for estimating the SCCO _2 and its uncertainty.

Published
2021
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results