Fast and slow components of the extratropical atmospheric circulation response to CO2 forcing
Poleward shifts of the extratropical atmospheric circulation are a common response to CO2 forcing in global climate models (GCMs), but little is known about the time dependence of this response. Here it is shown that in coupled climate models, the long-term evolution of sea surface temperatures (SST...
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ftimperialcol:oai:spiral.imperial.ac.uk:10044/1/74885 2023-05-15T13:53:11+02:00 Fast and slow components of the extratropical atmospheric circulation response to CO2 forcing Ceppi, P Zappa, G Shepherd, TG Gregory, JM 2017-09-15 http://hdl.handle.net/10044/1/74885 https://doi.org/10.1175/JCLI-D-17-0323.1 English eng American Meteorological Society Journal of Climate 0894-8755 http://hdl.handle.net/10044/1/74885 doi:10.1175/JCLI-D-17-0323.1 © 2018 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses). 1105 1091 Science & Technology Physical Sciences Meteorology & Atmospheric Sciences SEA-SURFACE TEMPERATURE CLIMATE-CHANGE TIME SCALES WARMING PATTERNS CARBON-DIOXIDE NORTH-ATLANTIC STORM-TRACK EL-NINO OCEAN MODEL CLIMATE SENSITIVITY CMIP5 PATTERNS FEEDBACK 0401 Atmospheric Sciences 0405 Oceanography 0909 Geomatic Engineering Journal Article 2017 ftimperialcol https://doi.org/10.1175/JCLI-D-17-0323.1 2021-02-18T23:38:57Z Poleward shifts of the extratropical atmospheric circulation are a common response to CO2 forcing in global climate models (GCMs), but little is known about the time dependence of this response. Here it is shown that in coupled climate models, the long-term evolution of sea surface temperatures (SSTs) induces two distinct time scales of circulation response to steplike CO2 forcing. In most GCMs from phase 5 of the Coupled Model Intercomparison Project as well as in the multimodel mean, all of the poleward shift of the midlatitude jets and Hadley cell edge occurs in a fast response within 5–10 years of the forcing, during which less than half of the expected equilibrium warming is realized. Compared with this fast response, the slow response over subsequent decades to centuries features stronger polar amplification (especially in the Antarctic), enhanced warming in the Southern Ocean, an El Niño–like pattern of tropical Pacific warming, and weaker land–sea contrast. Atmosphere-only GCM experiments demonstrate that the SST evolution drives the difference between the fast and slow circulation responses, although the direct radiative effect of CO2 also contributes to the fast response. It is further shown that the fast and slow responses determine the long-term evolution of the circulation response to warming in the representative concentration pathway 4.5 (RCP4.5) scenario. The results imply that shifts in midlatitude circulation generally scale with the radiative forcing, rather than with global-mean temperature change. A corollary is that time slices taken from a transient simulation at a given level of warming will considerably overestimate the extratropical circulation response in a stabilized climate. Article in Journal/Newspaper Antarc* Antarctic North Atlantic Southern Ocean Imperial College London: Spiral Antarctic Pacific Southern Ocean The Antarctic Journal of Climate 31 3 1091 1105 |
institution |
Open Polar |
collection |
Imperial College London: Spiral |
op_collection_id |
ftimperialcol |
language |
English |
topic |
Science & Technology Physical Sciences Meteorology & Atmospheric Sciences SEA-SURFACE TEMPERATURE CLIMATE-CHANGE TIME SCALES WARMING PATTERNS CARBON-DIOXIDE NORTH-ATLANTIC STORM-TRACK EL-NINO OCEAN MODEL CLIMATE SENSITIVITY CMIP5 PATTERNS FEEDBACK 0401 Atmospheric Sciences 0405 Oceanography 0909 Geomatic Engineering |
spellingShingle |
Science & Technology Physical Sciences Meteorology & Atmospheric Sciences SEA-SURFACE TEMPERATURE CLIMATE-CHANGE TIME SCALES WARMING PATTERNS CARBON-DIOXIDE NORTH-ATLANTIC STORM-TRACK EL-NINO OCEAN MODEL CLIMATE SENSITIVITY CMIP5 PATTERNS FEEDBACK 0401 Atmospheric Sciences 0405 Oceanography 0909 Geomatic Engineering Ceppi, P Zappa, G Shepherd, TG Gregory, JM Fast and slow components of the extratropical atmospheric circulation response to CO2 forcing |
topic_facet |
Science & Technology Physical Sciences Meteorology & Atmospheric Sciences SEA-SURFACE TEMPERATURE CLIMATE-CHANGE TIME SCALES WARMING PATTERNS CARBON-DIOXIDE NORTH-ATLANTIC STORM-TRACK EL-NINO OCEAN MODEL CLIMATE SENSITIVITY CMIP5 PATTERNS FEEDBACK 0401 Atmospheric Sciences 0405 Oceanography 0909 Geomatic Engineering |
description |
Poleward shifts of the extratropical atmospheric circulation are a common response to CO2 forcing in global climate models (GCMs), but little is known about the time dependence of this response. Here it is shown that in coupled climate models, the long-term evolution of sea surface temperatures (SSTs) induces two distinct time scales of circulation response to steplike CO2 forcing. In most GCMs from phase 5 of the Coupled Model Intercomparison Project as well as in the multimodel mean, all of the poleward shift of the midlatitude jets and Hadley cell edge occurs in a fast response within 5–10 years of the forcing, during which less than half of the expected equilibrium warming is realized. Compared with this fast response, the slow response over subsequent decades to centuries features stronger polar amplification (especially in the Antarctic), enhanced warming in the Southern Ocean, an El Niño–like pattern of tropical Pacific warming, and weaker land–sea contrast. Atmosphere-only GCM experiments demonstrate that the SST evolution drives the difference between the fast and slow circulation responses, although the direct radiative effect of CO2 also contributes to the fast response. It is further shown that the fast and slow responses determine the long-term evolution of the circulation response to warming in the representative concentration pathway 4.5 (RCP4.5) scenario. The results imply that shifts in midlatitude circulation generally scale with the radiative forcing, rather than with global-mean temperature change. A corollary is that time slices taken from a transient simulation at a given level of warming will considerably overestimate the extratropical circulation response in a stabilized climate. |
format |
Article in Journal/Newspaper |
author |
Ceppi, P Zappa, G Shepherd, TG Gregory, JM |
author_facet |
Ceppi, P Zappa, G Shepherd, TG Gregory, JM |
author_sort |
Ceppi, P |
title |
Fast and slow components of the extratropical atmospheric circulation response to CO2 forcing |
title_short |
Fast and slow components of the extratropical atmospheric circulation response to CO2 forcing |
title_full |
Fast and slow components of the extratropical atmospheric circulation response to CO2 forcing |
title_fullStr |
Fast and slow components of the extratropical atmospheric circulation response to CO2 forcing |
title_full_unstemmed |
Fast and slow components of the extratropical atmospheric circulation response to CO2 forcing |
title_sort |
fast and slow components of the extratropical atmospheric circulation response to co2 forcing |
publisher |
American Meteorological Society |
publishDate |
2017 |
url |
http://hdl.handle.net/10044/1/74885 https://doi.org/10.1175/JCLI-D-17-0323.1 |
geographic |
Antarctic Pacific Southern Ocean The Antarctic |
geographic_facet |
Antarctic Pacific Southern Ocean The Antarctic |
genre |
Antarc* Antarctic North Atlantic Southern Ocean |
genre_facet |
Antarc* Antarctic North Atlantic Southern Ocean |
op_source |
1105 1091 |
op_relation |
Journal of Climate 0894-8755 http://hdl.handle.net/10044/1/74885 doi:10.1175/JCLI-D-17-0323.1 |
op_rights |
© 2018 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses). |
op_doi |
https://doi.org/10.1175/JCLI-D-17-0323.1 |
container_title |
Journal of Climate |
container_volume |
31 |
container_issue |
3 |
container_start_page |
1091 |
op_container_end_page |
1105 |
_version_ |
1766258164723875840 |