Arctic sea ice anomalies during the MOSAiC winter 2019/20
As the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) project went into effect during the winter of 2019/2020, the Arctic Oscillation (AO) has experienced some of the largest shifts from a highly negative index in November 2019 to an extremely positive index during J...
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ftcopernicus:oai:publications.copernicus.org:tcd91964 2023-05-15T14:42:45+02:00 Arctic sea ice anomalies during the MOSAiC winter 2019/20 Dethloff, Klaus Maslowski, Wieslaw Hendricks, Stefan Lee, Younjoo Goessling, Helge F. Krumpen, Thomas Haas, Christian Handorf, Dörthe Ricker, Robert Bessonov, Vladimir Cassano, John J. Kinney, Jaclyn Clement Osinski, Robert Rex, Markus Rinke, Annette Sokolova, Julia Sommerfeld, Anja 2021-02-18 application/pdf https://doi.org/10.5194/tc-2020-375 https://tc.copernicus.org/preprints/tc-2020-375/ eng eng doi:10.5194/tc-2020-375 https://tc.copernicus.org/preprints/tc-2020-375/ eISSN: 1994-0424 Text 2021 ftcopernicus https://doi.org/10.5194/tc-2020-375 2021-02-22T17:22:15Z As the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) project went into effect during the winter of 2019/2020, the Arctic Oscillation (AO) has experienced some of the largest shifts from a highly negative index in November 2019 to an extremely positive index during January-February-March (JFM) 2020. Here we analyse the sea ice thickness (SIT) distribution based on CryoSat-2/SMOS satellite data augmented with results from the hindcast simulation by the fully coupled Regional Arctic System Model (RASM) for the time period from November 2019 through March 2020. A notable result of the positive AO phase during JFM 2020 were large SIT anomalies, up to 1.3 m, which emerged in the Barents-Sea (BS), along the northeastern Canadian coast and in parts of the central Arctic Ocean. These anomalies appear to be driven by nonlinear interactions between thermodynamic and dynamic processes. In particular, in the Barents- and Kara Seas (BKS) they are a result of an enhanced ice growth connected with the colder temperature anomalies and the consequence of intensified atmospheric-driven sea ice transport and deformations (i.e. divergence and shear) in this area. Low-pressure anomalies, which developed over the Eastern Arctic during JFM 2020, increased northerly winds from the cold Arctic Ocean to the BS and accelerated the southward drift of the MOSAiC ice floe. The satellite-derived and model-simulated sea ice velocity anomalies, which compared well during JFM 2020, indicate a strong acceleration of the Transpolar Drift relative to the mean for the past decade, with intensified speeds up to 6 km/day. As a consequence, sea ice transport and deformations driven by atmospheric wind forcing accounted for bulk of SIT anomalies, especially in January and February 2020. The unusual AO shift and the related sea ice anomalies during the MOSAiC winter 2019/20 are within the range of simulated states in the forecast ensemble. RASM intra-annual ensemble forecast simulations, forced with different atmospheric boundary conditions from November 1, 2019 through April 30, 2020, show a pronounced internally generated variability in the sea ice volume. A comparison of the respective SIT distribution and turbulent heat fluxes during the positive AO phase in JFM 2020 and the negative AO phase in JFM 2010 further corroborates the conclusion, that winter sea ice conditions of the Arctic Ocean can be significantly altered by AO variability. Text Arctic Arctic Ocean Barents Sea Sea ice Copernicus Publications: E-Journals Arctic Arctic Ocean Barents Sea |
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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 |
As the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) project went into effect during the winter of 2019/2020, the Arctic Oscillation (AO) has experienced some of the largest shifts from a highly negative index in November 2019 to an extremely positive index during January-February-March (JFM) 2020. Here we analyse the sea ice thickness (SIT) distribution based on CryoSat-2/SMOS satellite data augmented with results from the hindcast simulation by the fully coupled Regional Arctic System Model (RASM) for the time period from November 2019 through March 2020. A notable result of the positive AO phase during JFM 2020 were large SIT anomalies, up to 1.3 m, which emerged in the Barents-Sea (BS), along the northeastern Canadian coast and in parts of the central Arctic Ocean. These anomalies appear to be driven by nonlinear interactions between thermodynamic and dynamic processes. In particular, in the Barents- and Kara Seas (BKS) they are a result of an enhanced ice growth connected with the colder temperature anomalies and the consequence of intensified atmospheric-driven sea ice transport and deformations (i.e. divergence and shear) in this area. Low-pressure anomalies, which developed over the Eastern Arctic during JFM 2020, increased northerly winds from the cold Arctic Ocean to the BS and accelerated the southward drift of the MOSAiC ice floe. The satellite-derived and model-simulated sea ice velocity anomalies, which compared well during JFM 2020, indicate a strong acceleration of the Transpolar Drift relative to the mean for the past decade, with intensified speeds up to 6 km/day. As a consequence, sea ice transport and deformations driven by atmospheric wind forcing accounted for bulk of SIT anomalies, especially in January and February 2020. The unusual AO shift and the related sea ice anomalies during the MOSAiC winter 2019/20 are within the range of simulated states in the forecast ensemble. RASM intra-annual ensemble forecast simulations, forced with different atmospheric boundary conditions from November 1, 2019 through April 30, 2020, show a pronounced internally generated variability in the sea ice volume. A comparison of the respective SIT distribution and turbulent heat fluxes during the positive AO phase in JFM 2020 and the negative AO phase in JFM 2010 further corroborates the conclusion, that winter sea ice conditions of the Arctic Ocean can be significantly altered by AO variability. |
format |
Text |
author |
Dethloff, Klaus Maslowski, Wieslaw Hendricks, Stefan Lee, Younjoo Goessling, Helge F. Krumpen, Thomas Haas, Christian Handorf, Dörthe Ricker, Robert Bessonov, Vladimir Cassano, John J. Kinney, Jaclyn Clement Osinski, Robert Rex, Markus Rinke, Annette Sokolova, Julia Sommerfeld, Anja |
spellingShingle |
Dethloff, Klaus Maslowski, Wieslaw Hendricks, Stefan Lee, Younjoo Goessling, Helge F. Krumpen, Thomas Haas, Christian Handorf, Dörthe Ricker, Robert Bessonov, Vladimir Cassano, John J. Kinney, Jaclyn Clement Osinski, Robert Rex, Markus Rinke, Annette Sokolova, Julia Sommerfeld, Anja Arctic sea ice anomalies during the MOSAiC winter 2019/20 |
author_facet |
Dethloff, Klaus Maslowski, Wieslaw Hendricks, Stefan Lee, Younjoo Goessling, Helge F. Krumpen, Thomas Haas, Christian Handorf, Dörthe Ricker, Robert Bessonov, Vladimir Cassano, John J. Kinney, Jaclyn Clement Osinski, Robert Rex, Markus Rinke, Annette Sokolova, Julia Sommerfeld, Anja |
author_sort |
Dethloff, Klaus |
title |
Arctic sea ice anomalies during the MOSAiC winter 2019/20 |
title_short |
Arctic sea ice anomalies during the MOSAiC winter 2019/20 |
title_full |
Arctic sea ice anomalies during the MOSAiC winter 2019/20 |
title_fullStr |
Arctic sea ice anomalies during the MOSAiC winter 2019/20 |
title_full_unstemmed |
Arctic sea ice anomalies during the MOSAiC winter 2019/20 |
title_sort |
arctic sea ice anomalies during the mosaic winter 2019/20 |
publishDate |
2021 |
url |
https://doi.org/10.5194/tc-2020-375 https://tc.copernicus.org/preprints/tc-2020-375/ |
geographic |
Arctic Arctic Ocean Barents Sea |
geographic_facet |
Arctic Arctic Ocean Barents Sea |
genre |
Arctic Arctic Ocean Barents Sea Sea ice |
genre_facet |
Arctic Arctic Ocean Barents Sea Sea ice |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-2020-375 https://tc.copernicus.org/preprints/tc-2020-375/ |
op_doi |
https://doi.org/10.5194/tc-2020-375 |
_version_ |
1766314474185162752 |