Negligible Unforced Historical Pattern Effect on Climate Feedback Strength Found in HadISST-Based AMIP Simulations
Recently it has been suggested that natural variability in sea surface temperature (SST) patterns over the historical period causes a low bias in estimates of climate sensitivity based on instrumental records, in addition to that suggested by time variation of the climate feedback parameter in atmos...
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Stockholms universitet, Meteorologiska institutionen (MISU)
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ftstockholmuniv:oai:DiVA.org:su-192817 2023-05-15T18:18:08+02:00 Negligible Unforced Historical Pattern Effect on Climate Feedback Strength Found in HadISST-Based AMIP Simulations Lewis, Nicholas Mauritsen, Thorsten 2021 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-192817 https://doi.org/10.1175/JCLI-D-19-0941.1 eng eng Stockholms universitet, Meteorologiska institutionen (MISU) Journal of Climate, 0894-8755, 2021, 34:1, s. 39-55 http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-192817 doi:10.1175/JCLI-D-19-0941.1 ISI:000615484800003 info:eu-repo/semantics/openAccess Sea surface temperature Warm pool Climate sensitivity Feedback Regression analysis Earth and Related Environmental Sciences Geovetenskap och miljövetenskap Article in journal info:eu-repo/semantics/article text 2021 ftstockholmuniv https://doi.org/10.1175/JCLI-D-19-0941.1 2023-02-23T21:42:36Z Recently it has been suggested that natural variability in sea surface temperature (SST) patterns over the historical period causes a low bias in estimates of climate sensitivity based on instrumental records, in addition to that suggested by time variation of the climate feedback parameter in atmospheric general circulation models (GCMs) coupled to dynamic oceans. This excess, unforced, historical pattern effect (the effect of evolving surface temperature patterns on climate feedback strength) has been found in simulations performed using GCMs driven by AMIPII SST and sea ice changes (amipPiForcing). Here we show, in both amipPiForcing experiments with one GCM and by using Green's functions derived from another GCM, that whether such an unforced historical pattern effect is found depends on the underlying SST dataset used. When replacing the usual AMIPII SSTs with those from the HadISST1 dataset in amipPiForcing experiments, with sea ice changes unaltered, the first GCM indicates pattern effects that are indistinguishable from the forced pattern effect of the corresponding coupled GCM. Diagnosis of pattern effects using Green's functions derived from the second GCM supports this result for five out of six non-AMIPII SST reconstruction datasets. Moreover, internal variability in coupled GCMs is rarely sufficient to account for an unforced historical pattern effect of even one-quarter the strength previously reported. The presented evidence indicates that, if unforced pattern effects have been as small over the historical record as our findings suggest, they are unlikely to significantly bias climate sensitivity estimates that are based on long-term instrumental observations and account for forced pattern effects obtained from GCMs. Article in Journal/Newspaper Sea ice Stockholm University: Publications (DiVA) Journal of Climate 34 1 39 55 |
institution |
Open Polar |
collection |
Stockholm University: Publications (DiVA) |
op_collection_id |
ftstockholmuniv |
language |
English |
topic |
Sea surface temperature Warm pool Climate sensitivity Feedback Regression analysis Earth and Related Environmental Sciences Geovetenskap och miljövetenskap |
spellingShingle |
Sea surface temperature Warm pool Climate sensitivity Feedback Regression analysis Earth and Related Environmental Sciences Geovetenskap och miljövetenskap Lewis, Nicholas Mauritsen, Thorsten Negligible Unforced Historical Pattern Effect on Climate Feedback Strength Found in HadISST-Based AMIP Simulations |
topic_facet |
Sea surface temperature Warm pool Climate sensitivity Feedback Regression analysis Earth and Related Environmental Sciences Geovetenskap och miljövetenskap |
description |
Recently it has been suggested that natural variability in sea surface temperature (SST) patterns over the historical period causes a low bias in estimates of climate sensitivity based on instrumental records, in addition to that suggested by time variation of the climate feedback parameter in atmospheric general circulation models (GCMs) coupled to dynamic oceans. This excess, unforced, historical pattern effect (the effect of evolving surface temperature patterns on climate feedback strength) has been found in simulations performed using GCMs driven by AMIPII SST and sea ice changes (amipPiForcing). Here we show, in both amipPiForcing experiments with one GCM and by using Green's functions derived from another GCM, that whether such an unforced historical pattern effect is found depends on the underlying SST dataset used. When replacing the usual AMIPII SSTs with those from the HadISST1 dataset in amipPiForcing experiments, with sea ice changes unaltered, the first GCM indicates pattern effects that are indistinguishable from the forced pattern effect of the corresponding coupled GCM. Diagnosis of pattern effects using Green's functions derived from the second GCM supports this result for five out of six non-AMIPII SST reconstruction datasets. Moreover, internal variability in coupled GCMs is rarely sufficient to account for an unforced historical pattern effect of even one-quarter the strength previously reported. The presented evidence indicates that, if unforced pattern effects have been as small over the historical record as our findings suggest, they are unlikely to significantly bias climate sensitivity estimates that are based on long-term instrumental observations and account for forced pattern effects obtained from GCMs. |
format |
Article in Journal/Newspaper |
author |
Lewis, Nicholas Mauritsen, Thorsten |
author_facet |
Lewis, Nicholas Mauritsen, Thorsten |
author_sort |
Lewis, Nicholas |
title |
Negligible Unforced Historical Pattern Effect on Climate Feedback Strength Found in HadISST-Based AMIP Simulations |
title_short |
Negligible Unforced Historical Pattern Effect on Climate Feedback Strength Found in HadISST-Based AMIP Simulations |
title_full |
Negligible Unforced Historical Pattern Effect on Climate Feedback Strength Found in HadISST-Based AMIP Simulations |
title_fullStr |
Negligible Unforced Historical Pattern Effect on Climate Feedback Strength Found in HadISST-Based AMIP Simulations |
title_full_unstemmed |
Negligible Unforced Historical Pattern Effect on Climate Feedback Strength Found in HadISST-Based AMIP Simulations |
title_sort |
negligible unforced historical pattern effect on climate feedback strength found in hadisst-based amip simulations |
publisher |
Stockholms universitet, Meteorologiska institutionen (MISU) |
publishDate |
2021 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-192817 https://doi.org/10.1175/JCLI-D-19-0941.1 |
genre |
Sea ice |
genre_facet |
Sea ice |
op_relation |
Journal of Climate, 0894-8755, 2021, 34:1, s. 39-55 http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-192817 doi:10.1175/JCLI-D-19-0941.1 ISI:000615484800003 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1175/JCLI-D-19-0941.1 |
container_title |
Journal of Climate |
container_volume |
34 |
container_issue |
1 |
container_start_page |
39 |
op_container_end_page |
55 |
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1766194560127467520 |