Antarctic and Southern Ocean surface temperatures in CMIP5 models in the context of the surface energy budget
This study examines the biases, intermodel spread, and intermodel range of surface air temperature (SAT) across the Antarctic ice sheet and Southern Ocean in 26 structurally different climate models. Over the ocean (40°–60°S), an ensemble-mean warm bias peaks in late austral summer concurrently with...
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American Meteorological Society
2016
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ftncar:oai:drupal-site.org:articles_18097 2023-09-05T13:14:03+02:00 Antarctic and Southern Ocean surface temperatures in CMIP5 models in the context of the surface energy budget Schneider, David (author) Reusch, David (author) 2016-03-01 application/pdf http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-022-695 https://doi.org/10.1175/JCLI-D-15-0429.1 en eng American Meteorological Society Journal of Climate NCAR Command Language--10.5065/D6WD3XH5 articles:18097 ark:/85065/d75b0417 http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-022-695 doi:10.1175/JCLI-D-15-0429.1 Copyright 2016 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be "fair use" under Section 107 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Law (17 USC, as revised by P.L. 94-553) does not require the Society's permission. Republication, systematic reproduction, posting in electronic form on servers, or other uses of this material, except as exempted by the above statements, requires written permission or license from the AMS. Additional details are provided in the AMS Copyright Policies, available from the AMS at 617-227-2425 or amspubs@ametsoc.org. Permission to place a copy of this work on this server has been provided by the AMS. The AMS does not guarantee that the copy provided here is an accurate copy of the published work. Text article 2016 ftncar https://doi.org/10.1175/JCLI-D-15-0429.1 2023-08-14T18:44:56Z This study examines the biases, intermodel spread, and intermodel range of surface air temperature (SAT) across the Antarctic ice sheet and Southern Ocean in 26 structurally different climate models. Over the ocean (40°–60°S), an ensemble-mean warm bias peaks in late austral summer concurrently with the peak in the intermodel range of SAT. This warm bias lags a spring–summer positive bias in net surface radiation due to weak shortwave cloud forcing and is gradually reduced during autumn and winter. For the ice sheet, inconsistencies among reanalyses and observational datasets give low confidence in the ensemble-mean bias of SAT, but a small summer warm bias is suggested in comparison with nonreanalysis SAT data. The ensemble mean hides a large intermodel range of SAT, which peaks during the summer insolation maximum. In summer on the ice sheet, the SAT intermodel spread is largely associated with the surface albedo. In winter, models universally exhibit a too-strong deficit in net surface radiation related to the downward longwave radiation, implying that the lower atmosphere is too stable. This radiation deficit is balanced by the transfer of sensible heat toward the surface (which largely explains the intermodel spread in SAT) and by a subsurface heat flux. The winter bias in downward longwave radiation is due to the longwave cloud radiative effect, which the ensemble mean underestimates by a factor of 2. The implications of these results for improving climate simulations over Antarctica and the Southern Ocean are discussed. AGS-1048899 ANT1235231 Article in Journal/Newspaper Antarc* Antarctic Antarctica Ice Sheet Southern Ocean OpenSky (NCAR/UCAR - National Center for Atmospheric Research/University Corporation for Atmospheric Research) Antarctic Austral Southern Ocean The Antarctic Journal of Climate 29 5 1689 1716 |
institution |
Open Polar |
collection |
OpenSky (NCAR/UCAR - National Center for Atmospheric Research/University Corporation for Atmospheric Research) |
op_collection_id |
ftncar |
language |
English |
description |
This study examines the biases, intermodel spread, and intermodel range of surface air temperature (SAT) across the Antarctic ice sheet and Southern Ocean in 26 structurally different climate models. Over the ocean (40°–60°S), an ensemble-mean warm bias peaks in late austral summer concurrently with the peak in the intermodel range of SAT. This warm bias lags a spring–summer positive bias in net surface radiation due to weak shortwave cloud forcing and is gradually reduced during autumn and winter. For the ice sheet, inconsistencies among reanalyses and observational datasets give low confidence in the ensemble-mean bias of SAT, but a small summer warm bias is suggested in comparison with nonreanalysis SAT data. The ensemble mean hides a large intermodel range of SAT, which peaks during the summer insolation maximum. In summer on the ice sheet, the SAT intermodel spread is largely associated with the surface albedo. In winter, models universally exhibit a too-strong deficit in net surface radiation related to the downward longwave radiation, implying that the lower atmosphere is too stable. This radiation deficit is balanced by the transfer of sensible heat toward the surface (which largely explains the intermodel spread in SAT) and by a subsurface heat flux. The winter bias in downward longwave radiation is due to the longwave cloud radiative effect, which the ensemble mean underestimates by a factor of 2. The implications of these results for improving climate simulations over Antarctica and the Southern Ocean are discussed. AGS-1048899 ANT1235231 |
author2 |
Schneider, David (author) Reusch, David (author) |
format |
Article in Journal/Newspaper |
title |
Antarctic and Southern Ocean surface temperatures in CMIP5 models in the context of the surface energy budget |
spellingShingle |
Antarctic and Southern Ocean surface temperatures in CMIP5 models in the context of the surface energy budget |
title_short |
Antarctic and Southern Ocean surface temperatures in CMIP5 models in the context of the surface energy budget |
title_full |
Antarctic and Southern Ocean surface temperatures in CMIP5 models in the context of the surface energy budget |
title_fullStr |
Antarctic and Southern Ocean surface temperatures in CMIP5 models in the context of the surface energy budget |
title_full_unstemmed |
Antarctic and Southern Ocean surface temperatures in CMIP5 models in the context of the surface energy budget |
title_sort |
antarctic and southern ocean surface temperatures in cmip5 models in the context of the surface energy budget |
publisher |
American Meteorological Society |
publishDate |
2016 |
url |
http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-022-695 https://doi.org/10.1175/JCLI-D-15-0429.1 |
geographic |
Antarctic Austral Southern Ocean The Antarctic |
geographic_facet |
Antarctic Austral Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Antarctica Ice Sheet Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet Southern Ocean |
op_relation |
Journal of Climate NCAR Command Language--10.5065/D6WD3XH5 articles:18097 ark:/85065/d75b0417 http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-022-695 doi:10.1175/JCLI-D-15-0429.1 |
op_rights |
Copyright 2016 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be "fair use" under Section 107 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Law (17 USC, as revised by P.L. 94-553) does not require the Society's permission. Republication, systematic reproduction, posting in electronic form on servers, or other uses of this material, except as exempted by the above statements, requires written permission or license from the AMS. Additional details are provided in the AMS Copyright Policies, available from the AMS at 617-227-2425 or amspubs@ametsoc.org. Permission to place a copy of this work on this server has been provided by the AMS. The AMS does not guarantee that the copy provided here is an accurate copy of the published work. |
op_doi |
https://doi.org/10.1175/JCLI-D-15-0429.1 |
container_title |
Journal of Climate |
container_volume |
29 |
container_issue |
5 |
container_start_page |
1689 |
op_container_end_page |
1716 |
_version_ |
1776205118136385536 |