Evaluation of Different Methods to Assess Model Projections of the Future Evolution of the Atlantic Meridional Overturning Circulation
International audience Climate models predict a gradual weakening of the North Atlantic meridional overturning circulation (MOC) during the twenty-first century due to increasing levels of greenhouse gas concentrations in the atmosphere. Using an ensemble of 16 different coupled climate models perfo...
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ftceafr:oai:HAL:hal-03191695v1 2024-06-09T07:48:16+00:00 Evaluation of Different Methods to Assess Model Projections of the Future Evolution of the Atlantic Meridional Overturning Circulation Schneider, Birgit Latif, M. Schmittner, Andreas Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE) 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)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA) 2007-05-15 https://hal.science/hal-03191695 https://hal.science/hal-03191695/document https://hal.science/hal-03191695/file/JCLI4128.pdf https://doi.org/10.1175/JCLI4128.1 en eng HAL CCSD American Meteorological Society info:eu-repo/semantics/altIdentifier/doi/10.1175/JCLI4128.1 hal-03191695 https://hal.science/hal-03191695 https://hal.science/hal-03191695/document https://hal.science/hal-03191695/file/JCLI4128.pdf doi:10.1175/JCLI4128.1 info:eu-repo/semantics/OpenAccess ISSN: 0894-8755 EISSN: 1520-0442 Journal of Climate https://hal.science/hal-03191695 Journal of Climate, 2007, 20 (10), pp.2121-2132. ⟨10.1175/JCLI4128.1⟩ [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment info:eu-repo/semantics/article Journal articles 2007 ftceafr https://doi.org/10.1175/JCLI4128.1 2024-05-16T14:30:04Z International audience Climate models predict a gradual weakening of the North Atlantic meridional overturning circulation (MOC) during the twenty-first century due to increasing levels of greenhouse gas concentrations in the atmosphere. Using an ensemble of 16 different coupled climate models performed for the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC), the evolution of the MOC during the twentieth and twenty-first centuries is analyzed by combining model simulations for the IPCC scenarios Twentieth-Century Climate in Coupled Models (20C3M) and Special Report on Emission Scenarios, A1B (SRESA1B). Earlier findings are confirmed that even for the same forcing scenario the model response is spread over a large range. However, no model predicts abrupt changes or a total collapse of the MOC. To reduce the uncertainty of the projections, different weighting procedures are applied to obtain "best estimates" of the future MOC evolution, considering the skill of each model to represent present day hydrographic fields of temperature, salinity, and pycnocline depth as well as observation-based mass transport estimates. Using different methods of weighting the various models together, all produce estimates that the MOC will weaken by 25%-30% from present day values by the year 2100; however, absolute values of the MOC and the degree of reduction differ among the weighting methods. Article in Journal/Newspaper North Atlantic HAL-CEA (Commissariat à l'énergie atomique et aux énergies alternatives) Journal of Climate 20 10 2121 2132 |
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Open Polar |
collection |
HAL-CEA (Commissariat à l'énergie atomique et aux énergies alternatives) |
op_collection_id |
ftceafr |
language |
English |
topic |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment |
spellingShingle |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment Schneider, Birgit Latif, M. Schmittner, Andreas Evaluation of Different Methods to Assess Model Projections of the Future Evolution of the Atlantic Meridional Overturning Circulation |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment |
description |
International audience Climate models predict a gradual weakening of the North Atlantic meridional overturning circulation (MOC) during the twenty-first century due to increasing levels of greenhouse gas concentrations in the atmosphere. Using an ensemble of 16 different coupled climate models performed for the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC), the evolution of the MOC during the twentieth and twenty-first centuries is analyzed by combining model simulations for the IPCC scenarios Twentieth-Century Climate in Coupled Models (20C3M) and Special Report on Emission Scenarios, A1B (SRESA1B). Earlier findings are confirmed that even for the same forcing scenario the model response is spread over a large range. However, no model predicts abrupt changes or a total collapse of the MOC. To reduce the uncertainty of the projections, different weighting procedures are applied to obtain "best estimates" of the future MOC evolution, considering the skill of each model to represent present day hydrographic fields of temperature, salinity, and pycnocline depth as well as observation-based mass transport estimates. Using different methods of weighting the various models together, all produce estimates that the MOC will weaken by 25%-30% from present day values by the year 2100; however, absolute values of the MOC and the degree of reduction differ among the weighting methods. |
author2 |
Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE) 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)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA) |
format |
Article in Journal/Newspaper |
author |
Schneider, Birgit Latif, M. Schmittner, Andreas |
author_facet |
Schneider, Birgit Latif, M. Schmittner, Andreas |
author_sort |
Schneider, Birgit |
title |
Evaluation of Different Methods to Assess Model Projections of the Future Evolution of the Atlantic Meridional Overturning Circulation |
title_short |
Evaluation of Different Methods to Assess Model Projections of the Future Evolution of the Atlantic Meridional Overturning Circulation |
title_full |
Evaluation of Different Methods to Assess Model Projections of the Future Evolution of the Atlantic Meridional Overturning Circulation |
title_fullStr |
Evaluation of Different Methods to Assess Model Projections of the Future Evolution of the Atlantic Meridional Overturning Circulation |
title_full_unstemmed |
Evaluation of Different Methods to Assess Model Projections of the Future Evolution of the Atlantic Meridional Overturning Circulation |
title_sort |
evaluation of different methods to assess model projections of the future evolution of the atlantic meridional overturning circulation |
publisher |
HAL CCSD |
publishDate |
2007 |
url |
https://hal.science/hal-03191695 https://hal.science/hal-03191695/document https://hal.science/hal-03191695/file/JCLI4128.pdf https://doi.org/10.1175/JCLI4128.1 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
ISSN: 0894-8755 EISSN: 1520-0442 Journal of Climate https://hal.science/hal-03191695 Journal of Climate, 2007, 20 (10), pp.2121-2132. ⟨10.1175/JCLI4128.1⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1175/JCLI4128.1 hal-03191695 https://hal.science/hal-03191695 https://hal.science/hal-03191695/document https://hal.science/hal-03191695/file/JCLI4128.pdf doi:10.1175/JCLI4128.1 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1175/JCLI4128.1 |
container_title |
Journal of Climate |
container_volume |
20 |
container_issue |
10 |
container_start_page |
2121 |
op_container_end_page |
2132 |
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1801379927643127808 |