Arctic cloud annual cycle biases in climate models
Arctic clouds exhibit a robust annual cycle with maximum cloudiness in fall and minimum cloudiness in winter. These variations affect energy flows in the Arctic with a large influence on the surface radiative fluxes. Contemporary climate models struggle to reproduce the observed Arctic cloud amount...
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ftcopernicus:oai:publications.copernicus.org:acp72600 2023-05-15T14:43:16+02:00 Arctic cloud annual cycle biases in climate models Taylor, Patrick C. Boeke, Robyn C. Li, Ying Thompson, David W. J. 2019-07-10 application/pdf https://doi.org/10.5194/acp-19-8759-2019 https://www.atmos-chem-phys.net/19/8759/2019/ eng eng doi:10.5194/acp-19-8759-2019 https://www.atmos-chem-phys.net/19/8759/2019/ eISSN: 1680-7324 Text 2019 ftcopernicus https://doi.org/10.5194/acp-19-8759-2019 2019-12-24T09:48:59Z Arctic clouds exhibit a robust annual cycle with maximum cloudiness in fall and minimum cloudiness in winter. These variations affect energy flows in the Arctic with a large influence on the surface radiative fluxes. Contemporary climate models struggle to reproduce the observed Arctic cloud amount annual cycle and significantly disagree with each other. The goal of this analysis is to quantify the cloud-influencing factors that contribute to winter–summer cloud amount differences, as these seasons are primarily responsible for the model discrepancies with observations. We find that differences in the total cloud amount annual cycle are primarily caused by differences in low, rather than high, clouds; the largest differences occur between the surface and 950 hPa. Grouping models based on their seasonal cycles of cloud amount and stratifying cloud amount by cloud-influencing factors, we find that model groups disagree most under strong lower tropospheric stability, weak to moderate mid-tropospheric subsidence, and cold lower tropospheric air temperatures. Intergroup differences in low cloud amount are found to be a function of lower tropospheric thermodynamic characteristics. Further, we find that models with a larger low cloud amount in winter have a larger ice condensate fraction, whereas models with a larger low cloud amount in summer have a smaller ice condensate fraction. Stratifying model output by the specifics of the cloud microphysical scheme reveals that models treating cloud ice and liquid condensate as separate prognostic variables simulate a larger ice condensate fraction than those that treat total cloud condensate as a prognostic variable and use a temperature-dependent phase partitioning. Thus, the cloud microphysical parameterization is the primary cause of inter-model differences in the Arctic cloud annual cycle, providing further evidence of the important role that cloud ice microphysical processes play in the evolution and modeling of the Arctic climate system. Text Arctic Copernicus Publications: E-Journals Arctic Atmospheric Chemistry and Physics 19 13 8759 8782 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
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English |
description |
Arctic clouds exhibit a robust annual cycle with maximum cloudiness in fall and minimum cloudiness in winter. These variations affect energy flows in the Arctic with a large influence on the surface radiative fluxes. Contemporary climate models struggle to reproduce the observed Arctic cloud amount annual cycle and significantly disagree with each other. The goal of this analysis is to quantify the cloud-influencing factors that contribute to winter–summer cloud amount differences, as these seasons are primarily responsible for the model discrepancies with observations. We find that differences in the total cloud amount annual cycle are primarily caused by differences in low, rather than high, clouds; the largest differences occur between the surface and 950 hPa. Grouping models based on their seasonal cycles of cloud amount and stratifying cloud amount by cloud-influencing factors, we find that model groups disagree most under strong lower tropospheric stability, weak to moderate mid-tropospheric subsidence, and cold lower tropospheric air temperatures. Intergroup differences in low cloud amount are found to be a function of lower tropospheric thermodynamic characteristics. Further, we find that models with a larger low cloud amount in winter have a larger ice condensate fraction, whereas models with a larger low cloud amount in summer have a smaller ice condensate fraction. Stratifying model output by the specifics of the cloud microphysical scheme reveals that models treating cloud ice and liquid condensate as separate prognostic variables simulate a larger ice condensate fraction than those that treat total cloud condensate as a prognostic variable and use a temperature-dependent phase partitioning. Thus, the cloud microphysical parameterization is the primary cause of inter-model differences in the Arctic cloud annual cycle, providing further evidence of the important role that cloud ice microphysical processes play in the evolution and modeling of the Arctic climate system. |
format |
Text |
author |
Taylor, Patrick C. Boeke, Robyn C. Li, Ying Thompson, David W. J. |
spellingShingle |
Taylor, Patrick C. Boeke, Robyn C. Li, Ying Thompson, David W. J. Arctic cloud annual cycle biases in climate models |
author_facet |
Taylor, Patrick C. Boeke, Robyn C. Li, Ying Thompson, David W. J. |
author_sort |
Taylor, Patrick C. |
title |
Arctic cloud annual cycle biases in climate models |
title_short |
Arctic cloud annual cycle biases in climate models |
title_full |
Arctic cloud annual cycle biases in climate models |
title_fullStr |
Arctic cloud annual cycle biases in climate models |
title_full_unstemmed |
Arctic cloud annual cycle biases in climate models |
title_sort |
arctic cloud annual cycle biases in climate models |
publishDate |
2019 |
url |
https://doi.org/10.5194/acp-19-8759-2019 https://www.atmos-chem-phys.net/19/8759/2019/ |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic |
genre_facet |
Arctic |
op_source |
eISSN: 1680-7324 |
op_relation |
doi:10.5194/acp-19-8759-2019 https://www.atmos-chem-phys.net/19/8759/2019/ |
op_doi |
https://doi.org/10.5194/acp-19-8759-2019 |
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Atmospheric Chemistry and Physics |
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19 |
container_issue |
13 |
container_start_page |
8759 |
op_container_end_page |
8782 |
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