Search

Your search keyword '"Friedlingstein, Pierre"' showing total 946 results
Start Over Author "Friedlingstein, Pierre"
946 results on '"Friedlingstein, Pierre"'

351. On the causes of trends in the seasonal amplitude of atmospheric CO2.

Author

Piao, Shilong, Liu, Zhuo, Wang, Yilong, Ciais, Philippe, Yao, Yitong, Peng, Shushi, Chevallier, Frédéric, Friedlingstein, Pierre, Janssens, Ivan A., Peñuelas, Josep, Sitch, Stephen, and Wang, Tao

Subjects
ATMOSPHERIC carbon dioxide, ATMOSPHERIC chemistry, ATMOSPHERIC transport, BIOMES, TAIGAS
Abstract

Abstract: No consensus has yet been reached on the major factors driving the observed increase in the seasonal amplitude of atmospheric CO2 in the northern latitudes. In this study, we used atmospheric CO2 records from 26 northern hemisphere stations with a temporal coverage longer than 15 years, and an atmospheric transport model prescribed with net biome productivity (NBP) from an ensemble of nine terrestrial ecosystem models, to attribute change in the seasonal amplitude of atmospheric CO2. We found significant (p < .05) increases in seasonal peak‐to‐trough CO2 amplitude (AMPP‐T) at nine stations, and in trough‐to‐peak amplitude (AMPT‐P) at eight stations over the last three decades. Most of the stations that recorded increasing amplitudes are in Arctic and boreal regions (>50°N), consistent with previous observations that the amplitude increased faster at Barrow (Arctic) than at Mauna Loa (subtropics). The multi‐model ensemble mean (MMEM) shows that the response of ecosystem carbon cycling to rising CO2 concentration (eCO2) and climate change are dominant drivers of the increase in AMPP‐T and AMPT‐P in the high latitudes. At the Barrow station, the observed increase of AMPP‐T and AMPT‐P over the last 33 years is explained by eCO2 (39% and 42%) almost equally than by climate change (32% and 35%). The increased carbon losses during the months with a net carbon release in response to eCO2 are associated with higher ecosystem respiration due to the increase in carbon storage caused by eCO2 during carbon uptake period. Air‐sea CO2 fluxes (10% for AMPP‐T and 11% for AMPT‐P) and the impacts of land‐use change (marginally significant 3% for AMPP‐T and 4% for AMPT‐P) also contributed to the CO2 measured at Barrow, highlighting the role of these factors in regulating seasonal changes in the global carbon cycle. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

352. Fossil CO2emissions in the post-COVID-19 era

Author

Le Quéré, Corinne, Peters, Glen P., Friedlingstein, Pierre, Andrew, Robbie M., Canadell, Josep G., Davis, Steven J., Jackson, Robert B., and Jones, Matthew W.

Abstract

Five years after the adoption of the Paris Climate Agreement, growth in global CO2emissions has begun to falter. The pervasive disruptions from the COVID-19 pandemic have radically altered the trajectory of global CO2emissions. Contradictory effects of the post-COVID-19 investments in fossil fuel-based infrastructure and the recent strengthening of climate targets must be addressed with new policy choices to sustain a decline in global emissions in the post-COVID-19 era.

Published
2021
Full Text
View/download PDF

353. Three-dimensional transport and concentration of SF6

Author

Denning, A. Scott, Holzer, Mark, Gurney, Kevin R., Heimann, Martin, Law, Rachel M., Rayner, Peter J., Fung, Inez Y., Fan, Song-Miao, Taguchi, Shoichi, Friedlingstein, Pierre, Balkanski, Yves, Taylor, John, Maiss, Manfred, and Levin, Ingeborg

Abstract

Sulfur hexafluoride (SF6) is an excellent tracer of large-scale atmospheric transport, because it has slowly increasing sources mostly confined to northern midlatitudes, and has a lifetime of thousands of years. We have simulated the emissions, transport, and concentration of SF6 for a 5-year period, and compared the results with atmospheric observations. In addition, we have performed an intercomparison of interhemispheric transport among 11 models to investigate the reasons for the differences among the simulations. Most of the models are reasonably successful at simulating the observed meridional gradient of SF6 in the remote marine boundary layer, though there is less agreement at continental sites. Models that compare well to observations in the remote marine boundary layer tend to systematically overestimate SF6 at continental locations in source regions, suggesting that vertical trapping rather than meridional transport may be a dominant control on the simulated meridional gradient. The vertical structure of simulated SF6 in the models supports this interpretation. Some of the models perform quite well in terms of the simulated seasonal cycle at remote locations, while others do not. Interhemispheric exchange time varies by a factor of 2 when estimated from 1-dimensional meridional profiles at the surface, as has been done for observations. The agreement among models is better when the global surface mean mole fraction is used, and better still when the full 3-dimensional mean mixing ratio is used. The ranking of the interhemispheric exchange time among the models is not sensitive to the change from station values to surface means, but is very sensitive to the change from surface means to the full 3-dimensional tracer fields. This strengthens the argument that vertical redistribution dominates over interhemispheric transport in determining the meridional gradient at the surface. Vertically integrated meridional transport in the models is divided roughly equally into transport by the mean motion, the standing eddies, and the transient eddies. The vertically integrated mass flux is a good index of the degree to which resolved advection vs. parameterized diffusion accomplishes the meridional transport of SF6. Observational programs could provide a much better constraint on simulated chemical tracer transport if they included regular sampling of vertical profiles of nonreactive trace gases over source regions and meridional profiles in the middle to upper troposphere. Further analysis of the SF6simulations will focus on the subgrid-scale parameterized transports.DOI: 10.1034/j.1600-0889.1999.00012.x

Published
2011

354. Can a strong atmospheric CO2 rectifier effect be reconciled with a 'reasonable' carbon budget?

Author

Denning, A. Scott, Takahashi, Taro, and Friedlingstein, Pierre

Abstract

Atmospheric CO2 accumulates near the Earth's surface because of relatively deeper vertical mixing when photosynthesis is active than when it is not. Some models simulate an excess of more than 2.5 ppmv CO2 in the remote Northern Hemisphere due to this ‘‘rectification’′ of an annually balanced terrestrial carbon cycle. The covariance between CO2 flux and vertical mixing, and the resulting vertical structure of CO2 are generally consistent with field data at local scales, but it is difficult to reconcile such a strong rectifier signal with current ideas about the global carbon budget. A rectifier effect of 2.5 ppmv at northern flask sampling stations implies an unreasonably strong northern sink of atmospheric CO2, and a corresponding source in the tropics or Southern Hemisphere.DOI: 10.1034/j.1600-0889.1999.t01-1-00010.x

Published
2011

355. The relationship between peak warming and cumulative CO2emissions, and its use to quantify vulnerabilities in the carbon–climate–human system

Author

Raupach, Michael R., Canadell, Josep G., Ciais, Philippe, Friedlingstein, Pierre, Rayner, Peter J., and Trudinger, Catherine M.

Subjects
Atmospheric Science
Abstract

Interactions between the carbon cycle, climate and human societies are subject to several major vulnerabilities, broadly defined as factors contributing to the risk of harm from human-induced climate change. We assess five vulnerabilities: (1) effects of increasing CO2 on the partition of anthropogenic carbon between atmospheric, land and ocean reservoirs; (2) effects of climate change (quantified by temperature) on CO2 fluxes; (3) uncertainty in climate sensitivity; (4) non-CO2 radiative forcing and (5) anthropogenic CO2 emissions. Our analysis uses a physically based expression for Tp(Qp), the peak warming Tp associated with a cumulative anthropogenic CO2 emission Qp to the time of peak warming. The approximations in this expression are evaluated using a non-linear box model of the carbon–climate system, forced with capped emissions trajectories described by an analytic form satisfying integral and smoothness constraints. The first four vulnerabilities appear as parameters that influence Tp(Qp), whereas the last appears through the independent variable. In terms of likely implications for Tp(Qp), the decreasing order of the first four vulnerabilities is: uncertainties in climate sensitivity, effects of non-CO2 radiative forcing, effects of climate change on CO2 fluxes and effects of increasing CO2 on the partition of anthropogenic carbon.DOI: 10.1111/j.1600-0889.2010.00521.x

Published
2011

356. The relationship between peak warming and cumulative CO 2 emissions, and its use to quantify vulnerabilities in the carbon-climate-human system

Author

Raupach, Michael, Canadell, Josep, Ciais, Philippe, Friedlingstein, Pierre, Rayner, Peter, Trudinger, Catherine, CSIRO Marine and Atmospheric Research (CSIRO-MAR), Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), 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), ICOS-ATC (ICOS-ATC), 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
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; Interactions between the carbon cycle, climate and human societies are subject to several major vulnerabilities, broadly defined as factors contributing to the risk of harm from human-induced climate change. We assess five vulnerabilities: (1) effects of increasing CO 2 on the partition of anthropogenic carbon between atmospheric, land and ocean reservoirs ; (2) effects of climate change (quantified by temperature) on CO 2 fluxes; (3) uncertainty in climate sensitivity; (4) non-CO 2 radiative forcing and (5) anthropogenic CO 2 emissions. Our analysis uses a physically based expression for T p (Q p), the peak warming T p associated with a cumulative anthropogenic CO 2 emission Q p to the time of peak warming. The approximations in this expression are evaluated using a non-linear box model of the carbon-climate system, forced with capped emissions trajectories described by an analytic form satisfying integral and smoothness constraints. The first four vulnerabilities appear as parameters that influence T p (Q p), whereas the last appears through the independent variable. In terms of likely implications for T p (Q p), the decreasing order of the first four vulnerabilities is: uncertainties in climate sensitivity, effects of non-CO 2 radiative forcing, effects of climate change on CO 2 fluxes and effects of increasing CO 2 on the partition of anthropogenic carbon.

Published
2011

357. Spatiotemporal patterns of terrestrial gross primary production: A review

Author

Anav, Alessandro, primary, Friedlingstein, Pierre, additional, Beer, Christian, additional, Ciais, Philippe, additional, Harper, Anna, additional, Jones, Chris, additional, Murray-Tortarolo, Guillermo, additional, Papale, Dario, additional, Parazoo, Nicholas C., additional, Peylin, Philippe, additional, Piao, Shilong, additional, Sitch, Stephen, additional, Viovy, Nicolas, additional, Wiltshire, Andy, additional, and Zhao, Maosheng, additional

Published
2015
Full Text
View/download PDF

358. Multicriteria evaluation of discharge simulation in Dynamic Global Vegetation Models

Author

Yang, Hui, primary, Piao, Shilong, additional, Zeng, Zhenzhong, additional, Ciais, Philippe, additional, Yin, Yi, additional, Friedlingstein, Pierre, additional, Sitch, Stephen, additional, Ahlström, Anders, additional, Guimberteau, Matthieu, additional, Huntingford, Chris, additional, Levis, Sam, additional, Levy, Peter E., additional, Huang, Mengtian, additional, Li, Yue, additional, Li, Xiran, additional, Lomas, Mark R, additional, Peylin, Philippe, additional, Poulter, Ben, additional, Viovy, Nicolas, additional, Zaehle, Soenke, additional, Zeng, Ning, additional, Zhao, Fang, additional, and Wang, Lei, additional

Published
2015
Full Text
View/download PDF

359. The dominant role of semi-arid ecosystems in the trend and variability of the land CO 2 sink

Author

Ahlström, Anders, primary, Raupach, Michael R., additional, Schurgers, Guy, additional, Smith, Benjamin, additional, Arneth, Almut, additional, Jung, Martin, additional, Reichstein, Markus, additional, Canadell, Josep G., additional, Friedlingstein, Pierre, additional, Jain, Atul K., additional, Kato, Etsushi, additional, Poulter, Benjamin, additional, Sitch, Stephen, additional, Stocker, Benjamin D., additional, Viovy, Nicolas, additional, Wang, Ying Ping, additional, Wiltshire, Andy, additional, Zaehle, Sönke, additional, and Zeng, Ning, additional

Published
2015
Full Text
View/download PDF

361. Terrestrial nitrogen feedbacks may accelerate future climate change

Author

Zaehle, Sönke, Friedlingstein, Pierre, Friend, Andrew, 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), 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)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

The effects of nitrogen (N) constraints on future terrestrial carbon (C) dynamics are investigated using the O-CN land surface model. The model's responses to elevated [CO2] and soil warming agree well with observations made in ecosystem manipulation studies. N dynamics reduce terrestrial C storage due to CO2 fertilization over the period 1860-2100 by similar to 50% (342 Pg C) mainly in mid-high latitude ecosystems, compared to a simulation not accounting for N dynamics. Conversely, N dynamics reduce projected losses of land C due to increasing temperature by 16% (49 Pg C); however, this effect is prevalent only in mid-high latitude ecosystems. Despite synergistic interactions, the balance of these opposing effects is a significant reduction in future net land C storage. Terrestrial N dynamics thereby consistently increase atmospheric [CO2] in the year 2100 with a median value of 48 (41-55) ppmv, corresponding to an additional radiative forcing of 0.29 (0.28-0.34) W m(-2). Citation: Zaehle, S., P. Friedlingstein, and A. D. Friend (2010), Terrestrial nitrogen feedbacks may accelerate future climate change, Geophys. Res. Lett., 37, L01401, doi:10.1029/2009GL041345.

Published
2010

362. Evidence for a weakening relationship between interannual temperature variability and northern vegetation activity

Author

Piao, Shilong, primary, Nan, Huijuan, additional, Huntingford, Chris, additional, Ciais, Philippe, additional, Friedlingstein, Pierre, additional, Sitch, Stephen, additional, Peng, Shushi, additional, Ahlström, Anders, additional, Canadell, Josep G., additional, Cong, Nan, additional, Levis, Sam, additional, Levy, Peter E., additional, Liu, Lingli, additional, Lomas, Mark R., additional, Mao, Jiafu, additional, Myneni, Ranga B., additional, Peylin, Philippe, additional, Poulter, Ben, additional, Shi, Xiaoying, additional, Yin, Guodong, additional, Viovy, Nicolas, additional, Wang, Tao, additional, Wang, Xuhui, additional, Zaehle, Soenke, additional, Zeng, Ning, additional, Zeng, Zhenzhong, additional, and Chen, Anping, additional

Published
2014
Full Text
View/download PDF

363. Spatiotemporal patterns of terrestrial carbon cycle during the 20th century

Author

Piao, Shilong, Ciais, Philippe, Friedlingstein, Pierre, De Noblet-Ducoudré, Nathalie, Cadule, Patricia, Viovy, Nicolas, Wang, Tao, College of Urban and Environmental Sciences [Beijing], Peking University [Beijing], 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), ICOS-ATC (ICOS-ATC), 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), Extrèmes : Statistiques, Impacts et Régionalisation (ESTIMR), Modélisation des Surfaces et Interfaces Continentales (MOSAIC), 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
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; [1] We evaluated how climate change, rising atmospheric CO 2 concentration, and land use change influenced the terrestrial carbon (C) cycle for the last century using a process-based ecosystem model. Over the last century, the modeled land use change emitted about 129 Pg of C to the atmosphere. About 76% (or 98 Pg C) of this emission, however, was offset by net C uptake on land driven by climate changes and rising atmospheric CO 2 concentration. Thus, the modeled net release of C from the terrestrial ecosystems to the atmosphere from 1901 to 2002 is about 31 Pg C. Global net primary productivity (NPP) has significantly increased by 14% during the last century, especially since the 1970s. From 1980 to 2002, global NPP increased with an average increase rate of 0.4% yr À1. At global scale, such an increase seems to be primarily attributed to the increase in atmospheric CO 2 concentration, and then to precipitation change. Over the last 2 decades, climate change and rising CO 2 forced the land carbon sink (1.6 Pg C yr À1 for 1980s and 2.2 Pg C yr À1 for 1990s) to be larger than land use change driven carbon emissions (1.0 Pg C yr À1 for 1980s and 1.2 Pg C yr À1 for 1990s), resulting a net land sink of 0.5 Pg C yr À1 in the 1980s and of 1.0 Pg C yr À1 in the 1990s. The largest C emission from land use change appeared in tropical regions with an average emission of 0.6 Pg C yr À1 in 1980s and 0.7 Pg C yr À1 in 1990s, which is slightly larger than net carbon uptake due to CO 2 fertilization and climate change. Thus, net carbon balance of tropical lands is close to neutral over the past 2 decades (about 0.13 Pg C yr À1 in 1980s and 0.03 Pg C yr À1 in 1990s). We also found that current global warming has already started accelerating C loss from terrestrial ecosystems, by enhanced decomposition of soil organic carbon. In response to warming trends only, the global net carbon uptake significantly decreased, offsetting about 70% of the increase in global net carbon uptake owing to CO 2 fertilization during 1980-2002. The global terrestrial C cycle also shows large year-to-year variations, and different regions have quite distinct dominant drivers. Generally, interannual changes of carbon fluxes in tropical and temperate ecosystems are mainly explained by precipitation variability, while temperature variability plays a major role in boreal ecosystems.

Published
2009

364. Le GIEC. Pourquoi? Comment ?

Author

Friedlingstein, Pierre, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), 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)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2009

365. Global Climate Projections

Author

Meehl, Gerald A., Stocker, Thomas F., Collins, William D., Friedlingstein, Pierre, Gaye, Amadou T., Gregory, Jonathan M., Kitoh, Akio, Knutti, Reto, Murphy, James M., Noda, Akira, Raper, Sarah C.B., Watterson, Ian G., Weaver, Andrew J., and Zhao, Zong-Ci

Subjects
530 Physics
Abstract

The future climate change results assessed in this chapter are based on a hierarchy of models, ranging from Atmosphere-Ocean General Circulation Models (AOGCMs) and Earth System Models of Intermediate Complexity (EMICs) to Simple Climate Models (SCMs). These models are forced with concentrations of greenhouse gases and other constituents derived from various emissions scenarios ranging from non- mitigation scenarios to idealised long-term scenarios. In general, we assess non-mitigated projections of future climate change at scales from global to hundreds of kilometres. Further assessments of regional and local climate changes are provided in Chapter 11. Due to an unprecedented, joint effort by many modelling groups worldwide, climate change projections are now based on multi-model means, differences between models can be assessed quantitatively and in some instances, estimates of the probability of change of important climate system parameters complement expert judgement. New results corroborate those given in the Third Assessment Report (TAR). Continued greenhouse gas emissions at or above current rates will cause further warming and induce many changes in the global climate system during the 21st century that would very likely be larger than those observed during the 20th century.

Published
2007
Full Text
View/download PDF

366. Growing season extension and its impact on terrestrial carbon cycle in the Northern Hemisphere over the past 2 decades

Author

Piao, Shilong, Friedlingstein, Pierre, Ciais, Philippe, Viovy, Nicolas, Demarty, Jérôme, 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), ICOS-ATC (ICOS-ATC), 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), Modélisation des Surfaces et Interfaces Continentales (MOSAIC), 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
[SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology
Abstract

International audience; A number of studies have suggested that the growing season duration has significantly lengthened during the past decades, but the connections between phenology variability and the terrestrial carbon (C) cycle are far from clear. In this study, we used the “ORganizing Carbon and Hydrology In Dynamic Ecosystems” (ORCHIDEE) process based ecosystem model together with observed climate data to investigate spatiotemporal changes in phenology and their impacts on carbon fluxes in the Northern Hemisphere (>25°N) during 1980–2002. We found that the growing season length (GSL) has increased by 0.30 days yr−1 (R2 = 0.27, P = 0.010), owing to the combination of an earlier onset in spring (0.16 days yr−1) and a later termination in autumn (0.14 days yr−1). Trends in the GSL are however highly variable across the regions. In Eurasia, there is a significant trend toward earlier vegetation green‐up with an overall advancement rate of 0.28 days yr−1 (R2 = 0.32, P = 0.005), while in North America there is a significantly delayed vegetation senescence by 0.28 days yr−1 (R2 = 0.26, P = 0.013) during the study period. Our results also suggested that the GSL strongly correlates with annual gross primary productivity (GPP) and net primary productivity (NPP), indicating that longer growing seasons may eventually enhance vegetation growth. A 1‐day extension in GSL leads to an increase in annual GPP of 5.8 gC m−2 yr−1 (or 0.6% per day), and an increase in NPP of 2.8 gC m−2 yr−1 per day. However, owing to enhanced soil carbon decomposition accompanying the GPP increase, a change in GSL correlates only poorly with a change in annual net ecosystem productivity (NEP).

Published
2007

367. Le défi du changement climatique

Author

Friedlingstein, Pierre, Jouzel, Jean, 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), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), 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), 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
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2007

368. Summary for Policymakers

Author

Alley, Richard B., Berntsen, Terje, Bindoff, Nathaniel, Chidthaisong, Amnat, Friedlingstein, Pierre, Gregory, Jonathan, Hegerl, Gabriele, Heimann, Martin, Hewitson, Bruce, Hoskins, Brian, Joos, Fortunat, Jouzel, Jean, Kattsov, Vladimir, Lohmann, Ulrike, Manning, Martin, Matsuno, Taroh, Molina, Mario, Nicholls, Neville, Overpeck, Jonathan, Qin, Dahe, Raga, Graciela, Ramaswamy, Venkatachalam, Ren, Jiawen, Rusticucci, Matilde, Solomon, Susan, Somerville, Richard, Stocker, Thomas, Stott, Peter, Stouffer, Ronald, Whetton, Penny, Wood, Richard, Wratt, David, Arblaster, J., Brasseur, G., Christensen, J.H., Denman, K.L., Fahey, D.W., Forster, P., Jansen, E., Jones, P.D., Knutti, R., Le Treut, H, Lemke, P., Meehl, G., Mote, P., Randall, D.A., Stone, D.A., Trenberth, K.E., Willebrand, J., Zwiers, F., Chen, Zhenlin, Marquis, M, Averyt, K, Tignor, M, Miller, H, 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), 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)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2007

369. What determines the magnitude of carbon cycle-climate feedbacks?

Author

Matthews, H. Damon, Eby, Michael, Ewen, Tracy, Friedlingstein, Pierre, Hawkins, Barbara, University of Zurich, Matthews, H Damon, 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), 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)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 2300 General Environmental Science, 10122 Institute of Geography, 2304 Environmental Chemistry, 1902 Atmospheric Science, 2306 Global and Planetary Change, 910 Geography & travel, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; Positive feedbacks between climate change and the carbon cycle have the potential to amplify the growth of atmospheric carbon dioxide and accelerate future climate warming. However, both the magnitude of and the processes which drive future carbon cycleclimate feedbacks remain highly uncertain. In this study, we use a coupled climate-carbon model to investigate how the response of vegetation photosynthesis to climate change contributes to the overall strength of carbon cycle-climate feedbacks. We find that the feedback strength is particularly sensitive to the model representation of the photosynthesis-temperature response, with lesser sensitivity to the parameterization of soil moisture and nitrogen availability. In all simulations, large feedbacks are associated with a climatic suppression of terrestrial primary productivity and consequent reduction of terrestrial carbon uptake. This process is particularly evident in the tropics and can explain a large part of the range of carbon cycle-climate feedbacks simulated by different coupled climate-carbon models.

Published
2007

370. Simulation de l'évolution récente et future du climat par les modèles du CNRM et de l'IPSL

Author

Dufresne, Jean-Louis, Salas y Mélia, David, Denvil, Sébastien, Tyteca, Sophie, Arzel, Olivier, Bony, Sandrine, Braconnot, Pascale, Brockmann, Patrick, Cadule, Patricia, Caubel, Arnaud, Chauvin, Fabrice, Déqué, Michel, Douville, Hervé, Fairhead, Laurent, Fichefet, Thierry, Foujols, Marie-Alice, Friedlingstein, Pierre, Guérémy, Jean-François, Hourdin, Frédéric, Idelkadi, Abderrahmane, Lévy, Claire, Madec, Gurvan, Marquet, Pascal, Marti, Olivier, Musat, Ionela, Planton, Serge, Royer, Jean-François, Swingedouw, Didier, Voldoire, Aurore, 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), 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 Pierre-Simon-Laplace (IPSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Institut d'Astronomie et de Géophysique Georges Lemaître (UCL-ASTR), Université Catholique de Louvain = Catholic University of Louvain (UCL), 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), Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID), 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), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), 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)), 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 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), 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), 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), 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 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)), and 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)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph]
Abstract

National audience; In support of the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) that should appear in early 2007, modelling groups world-wide have performed a huge coordinated exercise of climate change runs for the 20th and 21st century. In this paper we present the results of the two french climate models, from CNRM and IPSL. In particular we emphasise the progress made since the previous IPCC report and we identify which results are comparable among models and which strongly differ.; Dans le cadre de la préparation du 4e rapport du Groupe Intergouvernemental sur l'Evolution du Climat (GIEC) qui doit paraître début 2007, les principales équipes de modélisation du climat de part le monde ont réalisé un important exercice coordonné de simulation de l'évolution du climat au cours du 20e et du 21e siècle. Nous présentons ici les résultats obtenus par les modèles du CNRM et de l'IPSL, en évoquant les progrès réalisés depuis le précédent rapport du GIEC. Nous replacerons également nos résultats par rapport à ceux des autres modèles, et indiquerons les résultats qui sont communs à l'ensemble des modèles et ceux qui peuvent être différents.

Published
2006

371. Recent and futur climate change as simulated by the CNRM and IPSL models

Author

Dufresne, Jean-Louis, Salas Y Mélia, David, Denvil, Sébastien, Tyteca, Sophie, Arzel, Olivier, Bony, Sandrine, Braconnot, Pascale, Brockmann, Patrick, Cadule, Patricia, Caubel, Arnaud, Chauvin, Fabrice, Déqué, Michel, Douville, Hervé, Fairhead, Laurent, Fichefet, Thierry, Foujols, Marie-Alice, Friedlingstein, Pierre, Guérémy, Jean-François, Hourdin, Frédéric, Idelkadi, Abderrahmane, Lévy, Claire, Madec, Gurvan, Marquet, Pascal, Marti, Olivier, Musat, Ionela, Planton, Serge, Royer, Jean-François, Swingedouw, Didier, Voldoire, Aurore, 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), 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 Pierre-Simon-Laplace (IPSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Institut d'Astronomie et de Géophysique Georges Lemaître (UCL-ASTR), Université Catholique de Louvain = Catholic University of Louvain (UCL), 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), Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID), 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), Modélisation du climat (CLIM), 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)), 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), and 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)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph]
Abstract

National audience; In support of the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) that should appear in early 2007, modelling groups world-wide have performed a huge coordinated exercise of climate change runs for the 20th and 21st century. In this paper we present the results of the two french climate models, from CNRM and IPSL. In particular we emphasise the progress made since the previous IPCC report and we identify which results are comparable among models and which strongly differ.; Dans le cadre de la préparation du 4e rapport du Groupe Intergouvernemental sur l'Evolution du Climat (GIEC) qui doit paraître début 2007, les principales équipes de modélisation du climat de part le monde ont réalisé un important exercice coordonné de simulation de l'évolution du climat au cours du 20e et du 21e siècle. Nous présentons ici les résultats obtenus par les modèles du CNRM et de l'IPSL, en évoquant les progrès réalisés depuis le précédent rapport du GIEC. Nous replacerons également nos résultats par rapport à ceux des autres modèles, et indiquerons les résultats qui sont communs à l'ensemble des modèles et ceux qui peuvent être différents.

Published
2006

372. The new IPSL climate system model: IPSL-CM4

Author

Marti, Olivier, Braconnot, Pascale, Bellier, Jacques, Benshila, Rachid, Bony, Sandrine, Brockmann, Patrick, Cadule, Patricia, Caubel, Arnaud, Denvil, Sébastien, Dufresne, Jean-Louis, Fairhead, Laurent, Filiberti, Marie-Angèle, Foujols, Marie-Alice, Fichefet, Thierry, Friedlingstein, Pierre, Gosse, H., Grandpeix, Jean-Yves, Hourdin, Frédéric, Krinner, Gerhard, Lévy, Claire, Madec, Gurvan, Musat, I., de Noblet, Nathalie, Polcher, Jan, Talandier, Claude, Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID), 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)-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'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), Modélisation du climat (CLIM), Calcul Scientifique (CALCULS), Institut Pierre-Simon-Laplace (IPSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-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, 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), Extrèmes : Statistiques, Impacts et Régionalisation (ESTIMR), IPSL, 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), 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 Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), and Aptel, Florence

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, [SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

The estimate of future climate change and of its impact on the environment requires to increase our knowledge of the complex interactions between the atmosphere, the ocean, sea-ice, land surfaces and glaciers. These components are coupled through the cycles of energy and water, but also through biogeochemical cycles such as the carbon or the ozone cycles. One of the goals of the IPSL modeling community is to study how these different couplings can modulate climate and climate variability, and to determine how feedbacks in the Earth system control the response of climate to a perturbation such as the anthropogenic emissions of greenhouse gases. For this purpose, the Earth system model of the IPSL is developed as a modular suite of model components of the Earth system that can be use either as stand alone models or coupled to each other. This note presents the new features and results of the last version of the global IPSL coupled model that will be used to run the set of simulations planned for the next IPCC assessment. In particular, chapter 2 presents the model components of the coupled system, highlighting important features for the coupling or the quality of model simulations. Chapter 3 synthesise all the coupling procedures and the coupling environment, and chapter 4 discussed the major characteristics of the model climatology.

Published
2006

373. Representation of dissolved organic carbon in the JULES land surface model (vn4.4_JULES-DOCM).

Author

Nakhavali, Mahdi, Friedlingstein, Pierre, Lauerwald, Ronny, Jing Tang, Chadburn, Sarah, Camino-Serrano, Marta, Guenet, Bertrand, Harper, Anna, Walmsley, David, Peichl, Matthias, and Gielen, Bert

Subjects
*CARBON cycle, *CARBON compounds, *OCEAN, *MATHEMATICAL models
Abstract

Current global models of the carbon (C) cycle consider only vertical gas exchanges between terrestrial or oceanic reservoirs and the atmosphere, thus not considering lateral transport of carbon from the continents to the oceans. Therefore, those models implicitly consider that all the C which is not respired to the atmosphere is stored on land, hence overestimating the land C sink capability. A model that represents the whole continuum from atmosphere to land and into the ocean would provide better understanding of the Earth's C cycle and hence more reliable historical or future projections. We present an original representation of Dissolved Organic C (DOC) processes in the Joint UK Land Environment Simulator (JULES-DOCM). The standard version of JULES represents energy, water and carbon dynamics between vegetation, soil and atmosphere, while lateral fluxes only account for water run-off. Here we integrate a representation of DOC production in terrestrial ecosystems based on incomplete decomposition of organic matter, DOC decomposition within the soil column, and DOC export to the river network via leaching. The model performance is evaluated in five specific sites for which observations of soil DOC concentration are available. Results show that the model is able to reproduce the DOC concentration and controlling processes including leaching to the riverine system which is fundamental for integrating terrestrial and aquatic ecosystems. [ABSTRACT FROM AUTHOR]

Published
2017
Full Text
View/download PDF

374. Global Carbon Budget 2017.

Author

Le Quéré, Corinne, Andrew, Robbie M., Friedlingstein, Pierre, Sitch, Stephen, Pongratz, Julia, Manning, Andrew C., Korsbakken, Jan Ivar, Peters, Glen P., Canadell, Josep G., Jackson, Robert B., Boden, Thomas A., Tans, Pieter P., Andrews, Oliver D., Arora, Vivek K., Bakker, Dorothee C. E., Barbero, Leticia, Becker, Meike, Betts, Richard A., Bopp, Laurent, and Chevallier, Frédéric

Subjects
CARBON dioxide mitigation, CARBON offsetting, EFFECT of human beings on climate change
Abstract

Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere - the "global carbon budget" - is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. CO2 emissions from fossil fuels and industry (EFF) are based on energy statistics and cement production data, respectively, while emissions from land-use change (ELUC), mainly deforestation, are based on land-cover change data and bookkeeping models. The global atmospheric CO2 concentration is measured directly and its rate of growth (GATM) is computed from the annual changes in concentration. The ocean CO2 sink (SOCEAN) and terrestrial CO2 sink (SLAND) are estimated with global process models constrained by observations. The resulting carbon budget imbalance (BIM), the difference between the estimated total emissions and the estimated changes in the atmosphere, ocean, and terrestrial biosphere, is a measure of our imperfect data and understanding of the contemporary carbon cycle. All uncertainties are reported as ±1σ. For the last decade available (2007-2016), EFF was 9.4 ± 0.5 GtC yr-1, ELUC 1.3 ± 0.7 GtC yr-1, GATM 4.7 ± 0.1 GtC yr-1, SOCEAN 2.4 ± 0.5 GtC yr-1, and SLAND 3.0 ± 0.8 GtC yr-1, with a budget imbalance BIM of 0.6 GtC yr-1 indicating overestimated emissions and/or underestimated sinks. For year 2016 alone, the growth in EFF was approximately zero and emissions remained at 9.9 ± 0.5 GtC yr-1. Also for 2016, ELUC was 1.3 ± 0.7 GtC yr-1, GATM was 6.1 ± 0.2 GtC yr-1, SOCEAN was 2.6 ± 0.5 GtC yr-1 and SLAND was 2.7 ± 1.0 GtC yr-1, with a small BIM of -0.3 GtC. GATM continued to be higher in 2016 compared to the past decade (2007-2016), reflecting in part the higher fossil emissions and smaller SLAND for that year consistent with El Niño conditions. The global atmospheric CO2 concentration reached 402.8 ± 0.1 ppm averaged over 2016. For 2017, preliminary data indicate a renewed growth in EFF of +2.0 % (range of 0.8 % to 3.0 %) based on national emissions projections for China, USA, and India, and projections of Gross Domestic Product corrected for recent changes in the carbon intensity of the economy for the rest of the world. For 2017, initial data indicate an increase in atmospheric CO2 concentration of around 5.3 GtC (2.5 ppm), attributed to a combination of increasing emissions and receding El Niño conditions. This living data update documents changes in the methods and data sets used in this new global carbon budget compared with previous publications of this data set (Le Quéré et al., 2016; 2015b; 2015a; 2014; 2013). All results presented here can be downloaded from https://doi.org/10.18160/GCP-2017. [ABSTRACT FROM AUTHOR]

Published
2017
Full Text
View/download PDF

375. Compensatory water effects link yearly global land CO2 sink changes to temperature.

Author

Jung, Martin, Reichstein, Markus, Schwalm, Christopher R., Huntingford, Chris, Sitch, Stephen, Ahlström, Anders, Arneth, Almut, Camps-Valls, Gustau, Ciais, Philippe, Friedlingstein, Pierre, Gans, Fabian, Ichii, Kazuhito, Jain, Atul K., Kato, Etsushi, Papale, Dario, Poulter, Ben, Raduly, Botond, Rödenbeck, Christian, Tramontana, Gianluca, and Viovy, Nicolas

Abstract

Large interannual variations in the measured growth rate of atmospheric carbon dioxide (CO2) originate primarily from fluctuations in carbon uptake by land ecosystems. It remains uncertain, however, to what extent temperature and water availability control the carbon balance of land ecosystems across spatial and temporal scales. Here we use empirical models based on eddy covariance data and process-based models to investigate the effect of changes in temperature and water availability on gross primary productivity (GPP), terrestrial ecosystem respiration (TER) and net ecosystem exchange (NEE) at local and global scales. We find that water availability is the dominant driver of the local interannual variability in GPP and TER. To a lesser extent this is true also for NEE at the local scale, but when integrated globally, temporal NEE variability is mostly driven by temperature fluctuations. We suggest that this apparent paradox can be explained by two compensatory water effects. Temporal water-driven GPP and TER variations compensate locally, dampening water-driven NEE variability. Spatial water availability anomalies also compensate, leaving a dominant temperature signal in the year-to-year fluctuations of the land carbon sink. These findings help to reconcile seemingly contradictory reports regarding the importance of temperature and water in controlling the interannual variability of the terrestrial carbon balance. Our study indicates that spatial climate covariation drives the global carbon cycle response. [ABSTRACT FROM AUTHOR]

Published
2017
Full Text
View/download PDF

376. Reducing uncertainties in decadal variability of the global carbon budget with multiple datasets.

Author

Wei Li, Ciaisa, Philippe, Yilong Wang, Shushi Peng, Broquet, Grégoire, Ballantyne, Ashley P., Cooper, Leila, Canadell, Josep G., Friedlingstein, Pierre, Le Quéré, Corinne, Myneni, Ranga B., Peters, Glen P., Shilong Piao, and Pongratz, Julia

Subjects
CARBON cycle, EMISSIONS (Air pollution), FOSSIL fuels & the environment, CLIMATE change mitigation
Abstract

Conventional calculations of the global carbon budget infer the land sink as a residual between emissions, atmospheric accumulation, and the ocean sink. Thus, the land sink accumulates the errors from the other flux terms and bears the largest uncertainty. Here, we present a Bayesian fusion approach that combines multiple observations in different carbon reservoirs to optimize the land (B) and ocean (O) carbon sinks, land use change emissions (L), and indirectly fossil fuel emissions (F) from 1980 to 2014. Compared with the conventional approach, Bayesian optimization decreases the uncertainties in B by 41% and in O by 46%. The L uncertainty decreases by 47%, whereas F uncertainty is marginally improved through the knowledge of natural fluxes. Both ocean and net land uptake (B + L) rates have positive trends of 29± 8 and 37± 17 Tg C·y-2 since 1980, respectively. Our Bayesian fusion of multiple observations reduces uncertainties, thereby allowing us to isolate important variability in global carbon cycle processes. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

378. 7. L’usage des terres

Author

de Noblet-Ducoudré, Nathalie, primary, Davin, Édouard, additional, Laval, Katia, additional, Guimberteau, Matthieu, additional, Friedlingstein, Pierre, additional, and Delire, Christine, additional

Full Text
View/download PDF

379. Sharing a quota on cumulative carbon emissions

Author

Raupach, Michael R., primary, Davis, Steven J., additional, Peters, Glen P., additional, Andrew, Robbie M., additional, Canadell, Josep G., additional, Ciais, Philippe, additional, Friedlingstein, Pierre, additional, Jotzo, Frank, additional, van Vuuren, Detlef P., additional, and Le Quéré, Corinne, additional

Published
2014
Full Text
View/download PDF

381. Evaluation of Land Surface Models in Reproducing Satellite-Derived LAI over the High-Latitude Northern Hemisphere. Part I: Uncoupled DGVMs

Author

Murray-Tortarolo, Guillermo, primary, Anav, Alessandro, additional, Friedlingstein, Pierre, additional, Sitch, Stephen, additional, Piao, Shilong, additional, Zhu, Zaichun, additional, Poulter, Benjamin, additional, Zaehle, Soenke, additional, Ahlström, Anders, additional, Lomas, Mark, additional, Levis, Sam, additional, Viovy, Nicholas, additional, and Zeng, Ning, additional

Published
2013
Full Text
View/download PDF

382. Positive feedback of the carbon cycle on future change climate ch

Author

Friedlingstein, Pierre, Bopp, Laurent, Ciais, Philippe, Dufresne, Jean-Louis, Fairhead, Laurent, Le Treut, Hervé, Monfray, Patrick, Orr, James C., 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), ICOS-ATC (ICOS-ATC), 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), IPSL, 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
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Published
2000

383. Can a strong atmospheric CO 2 rectifier effect be reconciled with a 'reasonable' carbon budget?

Author

Denning, A. Scott, Takahashi, Taro, Friedlingstein, Pierre, Colorado State University [Fort Collins] (CSU), Lamont-Doherty Earth Observatory (LDEO), Columbia University [New York], 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), 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)

Subjects
[SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; Atmospheric CO2 accumulates near the Earth’s surface because of relatively deeper vertical mixing when photosynthesis is active than when it is not. Some models simulate an excess of more than 2.5 ppmv CO2 in the remote Northern Hemisphere due to this “rectification” of an annually balanced terrestrial carbon cycle. The covariance between CO2 flux and vertical mixing, and the resulting vertical structure of CO2 are generally consistent with field data at local scales, but it is difficult to reconcile such a strong rectifier signal with current ideas about the global carbon budget. A rectifier effect of 2.5 ppmv at northern flask sampling stations implies an unreasonably strong northern sink of atmospheric CO2, and a corresponding source in the tropics or Southern Hemisphere.

Published
1999

384. Three-dimensional transport and concentration of SF 6 A model intercomparison study (TransCom 2)

Author

Denning, A. Scott, Holzer, Mark, Gurney, Kevin, Heimann, Martin, Law, Rachel, Rayner, Peter, Fung, Inez, Fan, Song-Miao, Taguchi, Shoichi, Friedlingstein, Pierre, Balkanski, Yves, Taylor, John, Maiss, Manfred, Levin, Ingeborg, Adaptive Behaviour Research Group (ABRG), University of Sheffield [Sheffield], Max-Planck-Institut für Biogeochemie (MPI-BGC), School of Earth Sciences [Melbourne], Faculty of Science [Melbourne], University of Melbourne-University of Melbourne, Department of Earth and Planetary Science [UC Berkeley] (EPS), University of California [Berkeley], University of California-University of California, College of Engineering, Mathematics and Physical Sciences [Exeter] (EMPS), University of Exeter, 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), Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID), 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 für Umweltphysik [Heidelberg], Universität Heidelberg [Heidelberg], University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), 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), and Universität Heidelberg [Heidelberg] = Heidelberg University

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, [SDE.MCG]Environmental Sciences/Global Changes, [SDE]Environmental Sciences
Abstract

International audience; Sulfur hexafluoride (SF6) is an excellent tracer of large-scale atmospheric transport, because it has slowly increasing sources mostly confined to northern midlatitudes, and has a lifetime of thousands of years. We have simulated the emissions, transport, and concentration of SF6 for a 5-year period, and compared the results with atmospheric observations. In addition, we have performed an intercomparison of interhemispheric transport among 11 models to investigate the reasons for the differences among the simulations. Most of the models are reasonably Successful at simulating the observed meridional gradient of SF6 in the remote marine boundary layer, though there is less agreement at continental sites. Models that compare well to observations in the remote marine boundary layer tend to systematically overestimate SF6 at continental locations in source regions, suggesting that vertical trapping rather than meridional transport may be a dominant control on the simulated meridional gradient. The vertical structure of simulated SF6 in the models supports this interpretation. Some of the models perform quite well in terms of the simulated seasonal cycle at remote locations, while others do not. Interhemispheric exchange time varies by a factor of 2 when estimated from 1-dimensional meridional profiles at the surface, as has been done for observations. The agreement among models is better when the global surface mean mole fraction is used, and better still when the full 3-dimensional mean mixing ratio is used. The ranking of the interhemispheric exchange time among the models is not sensitive to the change from station values to surface means, but is very sensitive to the change from surface means to the full 3-dimensional tracer fields. This strengthens the argument that vertical redistribution dominates over interhemispheric transport in determining the meridional gradient at the surface. Vertically integrated meridional transport in the models is divided roughly equally into transport by the mean motion, the standing eddies, and the transient eddies. The vertically integrated mass flux is a good index of the degree to which resolved advection vs. parameterized diffusion accomplishes the meridional transport of SF6. Observational programs could provide a much better constraint on simulated chemical tracer transport if they included regular sampling of vertical profiles of nonreactive trace gases over source regions and meridional profiles in the middle to upper troposphere. Further analysis of the SF6 simulations will focus on the subgrid-scale parameterized transports.

Published
1999

386. Long-Term Climate Change Commitment and Reversibility: An EMIC Intercomparison

Author

Zickfeld, Kirsten, primary, Eby, Michael, primary, Weaver, Andrew J., primary, Alexander, Kaitlin, primary, Crespin, Elisabeth, primary, Edwards, Neil R., primary, Eliseev, Alexey V., primary, Feulner, Georg, primary, Fichefet, Thierry, primary, Forest, Chris E., primary, Friedlingstein, Pierre, primary, Goosse, Hugues, primary, Holden, Philip B., primary, Joos, Fortunat, primary, Kawamiya, Michio, primary, Kicklighter, David, primary, Kienert, Hendrik, primary, Matsumoto, Katsumi, primary, Mokhov, Igor I., primary, Monier, Erwan, primary, Olsen, Steffen M., primary, Pedersen, Jens O. P., primary, Perrette, Mahe, primary, Philippon-Berthier, Gwenaëlle, primary, Ridgwell, Andy, primary, Schlosser, Adam, primary, Schneider Von Deimling, Thomas, primary, Shaffer, Gary, primary, Sokolov, Andrei, primary, Spahni, Renato, primary, Steinacher, Marco, primary, Tachiiri, Kaoru, primary, Tokos, Kathy S., primary, Yoshimori, Masakazu, primary, Zeng, Ning, primary, and Zhao, Fang, primary

Published
2013
Full Text
View/download PDF

388. Anthropogenic perturbation of the carbon fluxes from land to ocean

Author

Regnier, Pierre, primary, Friedlingstein, Pierre, additional, Ciais, Philippe, additional, Mackenzie, Fred T., additional, Gruber, Nicolas, additional, Janssens, Ivan A., additional, Laruelle, Goulven G., additional, Lauerwald, Ronny, additional, Luyssaert, Sebastiaan, additional, Andersson, Andreas J., additional, Arndt, Sandra, additional, Arnosti, Carol, additional, Borges, Alberto V., additional, Dale, Andrew W., additional, Gallego-Sala, Angela, additional, Goddéris, Yves, additional, Goossens, Nicolas, additional, Hartmann, Jens, additional, Heinze, Christoph, additional, Ilyina, Tatiana, additional, Joos, Fortunat, additional, LaRowe, Douglas E., additional, Leifeld, Jens, additional, Meysman, Filip J. R., additional, Munhoven, Guy, additional, Raymond, Peter A., additional, Spahni, Renato, additional, Suntharalingam, Parvadha, additional, and Thullner, Martin, additional

Published
2013
Full Text
View/download PDF

389. Evaluation of terrestrial carbon cycle models for their response to climate variability and to CO2trends

Author

Piao, Shilong, primary, Sitch, Stephen, additional, Ciais, Philippe, additional, Friedlingstein, Pierre, additional, Peylin, Philippe, additional, Wang, Xuhui, additional, Ahlström, Anders, additional, Anav, Alessandro, additional, Canadell, Josep G., additional, Cong, Nan, additional, Huntingford, Chris, additional, Jung, Martin, additional, Levis, Sam, additional, Levy, Peter E., additional, Li, Junsheng, additional, Lin, Xin, additional, Lomas, Mark R, additional, Lu, Meng, additional, Luo, Yiqi, additional, Ma, Yuecun, additional, Myneni, Ranga B., additional, Poulter, Ben, additional, Sun, ZhenZhong, additional, Wang, Tao, additional, Viovy, Nicolas, additional, Zaehle, Soenke, additional, and Zeng, Ning, additional

Published
2013
Full Text
View/download PDF

391. A modified impulse-response representation of the global response to carbon dioxide emissions.

Author

Millar, Richard J., Nicholls, Zebedee. R., Friedlingstein, Pierre, and Allen, Myles R.

Abstract

Projections of the response to anthropogenic emission scenarios, evaluation of some greenhouse gas metrics and estimates of the social cost of carbon, often require a simple model that links emissions of carbon dioxide CO2 to atmospheric concentrations and global temperature changes. An essential requirement of such a model is to reproduce the behaviour of more complex models as well as an ability to sample their range of response in a transparent, accessible and reproducible form. Here we adapt the simple model of the Intergovernmental Panel on Climate Change 5th Assessment Report (IPCC-AR5) to explicitly represent the state-dependence of the CO2 airborne fraction and reproduce several idealised experiments performed with more complex models. We find that a simple linear increase in 100-year integrated airborne fraction with cumulative carbon uptake and global temperature change is both necessary and sufficient to represent the response of the climate system to CO2 on a range of timescales and under a range of experimental designs. Quantified ranges of uncertainty (analogous to current assessed ranges in Equilibrium Climate Sensitivity and Transient Climate Response) in integrated airborne fraction over the 21st century under a representative mitigation scenario, and an assessed range in how much this quantity may have changed relative to pre-industrial conditions, would be valuable in future scientific assessments. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

392. Role of CO2, climate and land use in regulating the seasonal amplitude increase of carbon fluxes in terrestrial ecosystems: a multimodel analysis.

Author

Fang Zhao, Ning Zeng, Akihiko, Ito, Asrar, Ghassam, Friedlingstein, Pierre, Jain, Atul, Kalnay, Eugenia, Kato, Etsushi, Koven, Charles D., Poulter, Ben, Rafique, Rashid, Sitch, Stephen, Shu, Shijie, Stocker, Beni, Viovy, Nicolas, Wiltshire, Andy, and Zaehle, Sonke

Subjects
LAND use, CLIMATE change, CARBON cycle, TAIGAS, STATISTICAL correlation
Abstract

We examined the net terrestrial carbon flux to the atmosphere (FTA) simulated by nine models from the TRENDY dynamic global vegetation model project during 1961-2012 for its seasonal cycle and amplitude trend. While some models exhibit similar phase and amplitude compared to atmospheric inversions, with spring drawdown and autumn rebound, others tend to rebound early in summer. The model ensemble mean underestimates the magnitude of the seasonal cycle by 40% compared to atmospheric inversions. Global FTA amplitude increase (19 ± 8%) and its decadal variability from the model ensemble are generally consistent with constraints from surface atmosphere observations. However, models disagree on attribution of this long-term amplitude increase, with factorial experiments attributing 83 ± 56%, -3 ± 74% and 20 ± 30% to rising CO2, climate change and land use/cover change, respectively. Seven out of the nine models suggest that CO2 fertilization is a stronger control â€" with the notable exception of VEGAS, which attributes approximately equally to the three factors. Generally, all models display an enhanced seasonality over the boreal region in response to high-latitude warming, but a negative climate contribution from part of the Northern Hemisphere temperate region, and the net result is a divergence over climate change effect. Six of the nine models show land use/cover change amplifies the seasonal cycle of global FTA: some are due to forest regrowth while others are caused by crop expansion or agricultural intensification, as revealed by their divergent spatial patterns. We also discovered a moderate cross-model correlation between FTA amplitude increase and increase in land carbon sink (R² = 0.61). Our results suggest that models can show similar results in some benchmarks with different underlying mechanisms, therefore the spatial traits of CO2 fertilization, climate change, and land use/cover changes are crucial in determining the right mechanisms in seasonal carbon cycle change as well as mean sink change. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

393. The C4MIP experimental protocol for CMIP6.

Author

Jones, Chris D., Michio Kawamiya, Koven, Charlie, Randerson, Jim, Arora, Vivek, Friedlingstein, Pierre, Bopp, Laurent, Brovkin, Victor, Ilyina, Tatiana, Pongratz, Julia, Raddatz, Thomas, Dunne, John, John, Jasmin G., Graven, Heather, Hoffman, Forrest, Jung, Martin, and Zaehle, Sönke

Subjects
ATMOSPHERIC models, CARBON cycle, COMPARATIVE studies
Abstract

Coordinated experimental design and implementation has become a cornerstone of global climate modelling. So-called Model Intercomparison Projects (MIPs) enable systematic and robust analysis of results across many models to identify common signals and understand model similarities and differences without being hindered by ad-hoc differences in model set-up or experimental boundary conditions. The activity known as the Coupled Model Intercomparison Project (CMIP) has thus grown significantly in scope and as it enters its 6th phase, CMIP6, the design and documentation of individual simulations has been devolved to individual climate science communities. The Coupled Climate-Carbon Cycle Model Intercomparison Project (C4MIP) takes responsibility for design, documentation and analysis of carbon cycle feedbacks and interactions in climate simulations. These feedbacks are potentially large and play a leading order contribution in determining the atmospheric composition in response to human emissions of CO2 and in the setting of emissions targets to stabilise climate or avoid dangerous climate change. For over a decade C4MIP has coordinated coupled climate-carbon cycle simulations and in this paper we describe the C4MIP simulations that will be formally part of CMIP6. While the climate-carbon cycle community has formed this experimental design the simulations also fit into the wider CMIP activity and conform to some common standards such as documentation and diagnostic requests and are designed to complement the CMIP core experiments known as the DECK. C4MIP has 3 key strands of scientific motivation and the requested simulations are designed to satisfy their needs: (1) pre-industrial and historical simulations (formally part of the common set of CMIP6 experiments) to enable model evaluation; (2) idealised coupled and partially-coupled simulations with 1 % per year increases in CO2 to enable diagnosis of feedback strength and its components; (3) future scenario simulations to project how the Earth System will respond over the 21st century and beyond to anthropogenic activity. This paper documents in detail these simulations, explains their rationale and planned analysis, and describes how to set-up and run the simulations. Particular attention is paid to boundary conditions and input data required, and also the output diagnostics requested. It is important that modelling groups participating in C4MIP adhere as closely as possible to this experimental design. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

396. Compensatory water effects link yearly global land CO2sink changes to temperature

Author

Jung, Martin, Reichstein, Markus, Schwalm, Christopher R., Huntingford, Chris, Sitch, Stephen, Ahlström, Anders, Arneth, Almut, Camps-Valls, Gustau, Ciais, Philippe, Friedlingstein, Pierre, Gans, Fabian, Ichii, Kazuhito, Jain, Atul K., Kato, Etsushi, Papale, Dario, Poulter, Ben, Raduly, Botond, Rödenbeck, Christian, Tramontana, Gianluca, Viovy, Nicolas, Wang, Ying-Ping, Weber, Ulrich, Zaehle, Sönke, and Zeng, Ning

Abstract

Large interannual variations in the measured growth rate of atmospheric carbon dioxide (CO2) originate primarily from fluctuations in carbon uptake by land ecosystems. It remains uncertain, however, to what extent temperature and water availability control the carbon balance of land ecosystems across spatial and temporal scales. Here we use empirical models based on eddy covariance data and process-based models to investigate the effect of changes in temperature and water availability on gross primary productivity (GPP), terrestrial ecosystem respiration (TER) and net ecosystem exchange (NEE) at local and global scales. We find that water availability is the dominant driver of the local interannual variability in GPP and TER. To a lesser extent this is true also for NEE at the local scale, but when integrated globally, temporal NEE variability is mostly driven by temperature fluctuations. We suggest that this apparent paradox can be explained by two compensatory water effects. Temporal water-driven GPP and TER variations compensate locally, dampening water-driven NEE variability. Spatial water availability anomalies also compensate, leaving a dominant temperature signal in the year-to-year fluctuations of the land carbon sink. These findings help to reconcile seemingly contradictory reports regarding the importance of temperature and water in controlling the interannual variability of the terrestrial carbon balance. Our study indicates that spatial climate covariation drives the global carbon cycle response.

Published
2017
Full Text
View/download PDF

398. Surface Urban Heat Island Across 419 Global Big Cities

Author

Peng, Shushi, primary, Piao, Shilong, additional, Ciais, Philippe, additional, Friedlingstein, Pierre, additional, Ottle, Catherine, additional, Bréon, François-Marie, additional, Nan, Huijuan, additional, Zhou, Liming, additional, and Myneni, Ranga B., additional

Published
2011
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results