Mitigating climate biases in the midlatitude North Atlantic by increasing model resolution: SST gradients and their relation to blocking and the jet

Starting to resolve the oceanic mesoscale in climate models is a step change in model fidelity. This study examines how certain obstinate biases in the midlatitude North Atlantic respond to increasing resolution (from 1° to 0.25° in the ocean) and how such biases in sea surface temperature (SST) a...

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Main Authors: Athanasiadis, Panos J., Ogawa, Fumiaki, Omrani, Nour-Eddine, Keenlyside, Noel, Schiemann, Reinhard, Baker, Alexander J., Vidale, Pier Luigi, Bellucci, Alessio, Ruggieri, Paolo, Haarsma, Rein, Roberts, Malcolm, Roberts, Chris, Novak, Lenka, Gualdi, Silvio
Format: Article in Journal/Newspaper
Language:unknown
Published: American Meteorological Society 2022
Subjects:
Online Access:https://doi.org/10.1175/jcli-d-21-0515.1
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spelling ftcaltechauth:oai:authors.library.caltech.edu:13yk0-9ge31 2024-09-09T19:55:15+00:00 Mitigating climate biases in the midlatitude North Atlantic by increasing model resolution: SST gradients and their relation to blocking and the jet Athanasiadis, Panos J. Ogawa, Fumiaki Omrani, Nour-Eddine Keenlyside, Noel Schiemann, Reinhard Baker, Alexander J. Vidale, Pier Luigi Bellucci, Alessio Ruggieri, Paolo Haarsma, Rein Roberts, Malcolm Roberts, Chris Novak, Lenka Gualdi, Silvio 2022-11 https://doi.org/10.1175/jcli-d-21-0515.1 unknown American Meteorological Society https://doi.org/10.1175/JCLI-D-21-0515.1 oai:authors.library.caltech.edu:13yk0-9ge31 eprintid:117956 resolverid:CaltechAUTHORS:20221121-712406200.21 info:eu-repo/semantics/closedAccess Other Journal of Climate, 35(21), 3385-3406, (2022-11) Atmospheric Science info:eu-repo/semantics/article 2022 ftcaltechauth https://doi.org/10.1175/jcli-d-21-0515.110.1175/JCLI-D-21-0515.1 2024-08-06T15:35:04Z Starting to resolve the oceanic mesoscale in climate models is a step change in model fidelity. This study examines how certain obstinate biases in the midlatitude North Atlantic respond to increasing resolution (from 1° to 0.25° in the ocean) and how such biases in sea surface temperature (SST) affect the atmosphere. Using a multi-model ensemble of historical climate simulations run at different horizontal resolutions, it is shown that a severe cold SST bias in the central North Atlantic, common to many ocean models, is significantly reduced with increasing resolution. The associated bias in the time-mean meridional SST gradient is shown to relate to a positive bias in low-level baroclinicity, while the cold SST bias causes biases also in static stability and diabatic heating in the interior of the atmosphere. The changes in baroclinicity and diabatic heating brought by increasing resolution lead to improvements in European blocking and eddy-driven jet variability. Across the multi-model ensemble a clear relationship is found between the climatological meridional SST gradients in the broader Gulf Stream Extension area and two aspects of the atmospheric circulation: the frequency of high-latitude blocking and the southern-jet regime. This relationship is thought to reflect the two-way interaction (with a positive feedback) between the respective oceanic and atmospheric anomalies. These North Atlantic SST anomalies are shown to be important in forcing significant responses in the midlatitude atmospheric circulation, including jet variability and the stormtrack. Further increases in oceanic and atmospheric resolution are expected to lead to additional improvements in the representation of Euro-Atlantic climate. PJA and AB acknowledge funding from the PRIMAVERA project, funded by the European Union's Horizon 2020 programme under Grant Agreement 641727. MR acknowledges support from the Joint U.K. BEIS/Defra Met Office Hadley Centre Climate Programme (Grant GA01101). N-E. Omrani was supported by 1) the Bjerknes ... Article in Journal/Newspaper North Atlantic Caltech Authors (California Institute of Technology)
institution Open Polar
collection Caltech Authors (California Institute of Technology)
op_collection_id ftcaltechauth
language unknown
topic Atmospheric Science
spellingShingle Atmospheric Science
Athanasiadis, Panos J.
Ogawa, Fumiaki
Omrani, Nour-Eddine
Keenlyside, Noel
Schiemann, Reinhard
Baker, Alexander J.
Vidale, Pier Luigi
Bellucci, Alessio
Ruggieri, Paolo
Haarsma, Rein
Roberts, Malcolm
Roberts, Chris
Novak, Lenka
Gualdi, Silvio
Mitigating climate biases in the midlatitude North Atlantic by increasing model resolution: SST gradients and their relation to blocking and the jet
topic_facet Atmospheric Science
description Starting to resolve the oceanic mesoscale in climate models is a step change in model fidelity. This study examines how certain obstinate biases in the midlatitude North Atlantic respond to increasing resolution (from 1° to 0.25° in the ocean) and how such biases in sea surface temperature (SST) affect the atmosphere. Using a multi-model ensemble of historical climate simulations run at different horizontal resolutions, it is shown that a severe cold SST bias in the central North Atlantic, common to many ocean models, is significantly reduced with increasing resolution. The associated bias in the time-mean meridional SST gradient is shown to relate to a positive bias in low-level baroclinicity, while the cold SST bias causes biases also in static stability and diabatic heating in the interior of the atmosphere. The changes in baroclinicity and diabatic heating brought by increasing resolution lead to improvements in European blocking and eddy-driven jet variability. Across the multi-model ensemble a clear relationship is found between the climatological meridional SST gradients in the broader Gulf Stream Extension area and two aspects of the atmospheric circulation: the frequency of high-latitude blocking and the southern-jet regime. This relationship is thought to reflect the two-way interaction (with a positive feedback) between the respective oceanic and atmospheric anomalies. These North Atlantic SST anomalies are shown to be important in forcing significant responses in the midlatitude atmospheric circulation, including jet variability and the stormtrack. Further increases in oceanic and atmospheric resolution are expected to lead to additional improvements in the representation of Euro-Atlantic climate. PJA and AB acknowledge funding from the PRIMAVERA project, funded by the European Union's Horizon 2020 programme under Grant Agreement 641727. MR acknowledges support from the Joint U.K. BEIS/Defra Met Office Hadley Centre Climate Programme (Grant GA01101). N-E. Omrani was supported by 1) the Bjerknes ...
format Article in Journal/Newspaper
author Athanasiadis, Panos J.
Ogawa, Fumiaki
Omrani, Nour-Eddine
Keenlyside, Noel
Schiemann, Reinhard
Baker, Alexander J.
Vidale, Pier Luigi
Bellucci, Alessio
Ruggieri, Paolo
Haarsma, Rein
Roberts, Malcolm
Roberts, Chris
Novak, Lenka
Gualdi, Silvio
author_facet Athanasiadis, Panos J.
Ogawa, Fumiaki
Omrani, Nour-Eddine
Keenlyside, Noel
Schiemann, Reinhard
Baker, Alexander J.
Vidale, Pier Luigi
Bellucci, Alessio
Ruggieri, Paolo
Haarsma, Rein
Roberts, Malcolm
Roberts, Chris
Novak, Lenka
Gualdi, Silvio
author_sort Athanasiadis, Panos J.
title Mitigating climate biases in the midlatitude North Atlantic by increasing model resolution: SST gradients and their relation to blocking and the jet
title_short Mitigating climate biases in the midlatitude North Atlantic by increasing model resolution: SST gradients and their relation to blocking and the jet
title_full Mitigating climate biases in the midlatitude North Atlantic by increasing model resolution: SST gradients and their relation to blocking and the jet
title_fullStr Mitigating climate biases in the midlatitude North Atlantic by increasing model resolution: SST gradients and their relation to blocking and the jet
title_full_unstemmed Mitigating climate biases in the midlatitude North Atlantic by increasing model resolution: SST gradients and their relation to blocking and the jet
title_sort mitigating climate biases in the midlatitude north atlantic by increasing model resolution: sst gradients and their relation to blocking and the jet
publisher American Meteorological Society
publishDate 2022
url https://doi.org/10.1175/jcli-d-21-0515.1
genre North Atlantic
genre_facet North Atlantic
op_source Journal of Climate, 35(21), 3385-3406, (2022-11)
op_relation https://doi.org/10.1175/JCLI-D-21-0515.1
oai:authors.library.caltech.edu:13yk0-9ge31
eprintid:117956
resolverid:CaltechAUTHORS:20221121-712406200.21
op_rights info:eu-repo/semantics/closedAccess
Other
op_doi https://doi.org/10.1175/jcli-d-21-0515.110.1175/JCLI-D-21-0515.1
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