Atmospheric response to removal of Southern Hemisphere sea ice - a model study
The atmospheric response to the removal of Southern Hemisphere sea ice is studied using the ICTP AGCM (SPEEDY) model with an uncoupled ocean. The results show large increases in surface heat flux from the ocean to the atmosphere over areas with sea ice removed. The increased heat flux is accompanied...
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The University of Bergen
2010
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ftunivbergen:oai:bora.uib.no:1956/7079 2023-05-15T18:17:19+02:00 Atmospheric response to removal of Southern Hemisphere sea ice - a model study Ravnestad, Kristen Myklebust 2010-06-01 15344523 bytes application/pdf https://hdl.handle.net/1956/7079 eng eng The University of Bergen https://hdl.handle.net/1956/7079 Copyright the author. All rights reserved 756213 Master thesis 2010 ftunivbergen 2023-03-14T17:43:27Z The atmospheric response to the removal of Southern Hemisphere sea ice is studied using the ICTP AGCM (SPEEDY) model with an uncoupled ocean. The results show large increases in surface heat flux from the ocean to the atmosphere over areas with sea ice removed. The increased heat flux is accompanied by an intense and shallow atmospheric warming in the annual and austral winter mean. Warming in the lower troposphere is associated with a positive geopotential height response that is usually equivalent barotropic. This atmospheric response is present in the annual and the austral winter means, with the largest magnitudes during the austral winter. A baroclinic pattern is found in the late summer (March) response. A comparison between the maximum theoretical local response and the model simulated response for September and March indicates a more non-local component of the response during March. A dipole response in the zonal wind field which is consistent with the geopotential height anomalies is found in the annual and austral seasonal mean. The eddy-driven midlatitude jet is weakened and shifted equatorward, while the subtropical jet is barely affected. Using empirical orthogonal function analysis, the Southern Hemisphere geopotential height variability has been investigated. A somewhat weaker Southern Annular Mode results within the simulation of removed sea ice and this result appears to be broadly consistent with the weaker eddy-driven jet. Master i Meteorologi og oseanografi MAMN-GEOF GEOF399 Master Thesis Sea ice University of Bergen: Bergen Open Research Archive (BORA-UiB) Austral |
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Open Polar |
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University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
topic |
756213 |
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756213 Ravnestad, Kristen Myklebust Atmospheric response to removal of Southern Hemisphere sea ice - a model study |
topic_facet |
756213 |
description |
The atmospheric response to the removal of Southern Hemisphere sea ice is studied using the ICTP AGCM (SPEEDY) model with an uncoupled ocean. The results show large increases in surface heat flux from the ocean to the atmosphere over areas with sea ice removed. The increased heat flux is accompanied by an intense and shallow atmospheric warming in the annual and austral winter mean. Warming in the lower troposphere is associated with a positive geopotential height response that is usually equivalent barotropic. This atmospheric response is present in the annual and the austral winter means, with the largest magnitudes during the austral winter. A baroclinic pattern is found in the late summer (March) response. A comparison between the maximum theoretical local response and the model simulated response for September and March indicates a more non-local component of the response during March. A dipole response in the zonal wind field which is consistent with the geopotential height anomalies is found in the annual and austral seasonal mean. The eddy-driven midlatitude jet is weakened and shifted equatorward, while the subtropical jet is barely affected. Using empirical orthogonal function analysis, the Southern Hemisphere geopotential height variability has been investigated. A somewhat weaker Southern Annular Mode results within the simulation of removed sea ice and this result appears to be broadly consistent with the weaker eddy-driven jet. Master i Meteorologi og oseanografi MAMN-GEOF GEOF399 |
format |
Master Thesis |
author |
Ravnestad, Kristen Myklebust |
author_facet |
Ravnestad, Kristen Myklebust |
author_sort |
Ravnestad, Kristen Myklebust |
title |
Atmospheric response to removal of Southern Hemisphere sea ice - a model study |
title_short |
Atmospheric response to removal of Southern Hemisphere sea ice - a model study |
title_full |
Atmospheric response to removal of Southern Hemisphere sea ice - a model study |
title_fullStr |
Atmospheric response to removal of Southern Hemisphere sea ice - a model study |
title_full_unstemmed |
Atmospheric response to removal of Southern Hemisphere sea ice - a model study |
title_sort |
atmospheric response to removal of southern hemisphere sea ice - a model study |
publisher |
The University of Bergen |
publishDate |
2010 |
url |
https://hdl.handle.net/1956/7079 |
geographic |
Austral |
geographic_facet |
Austral |
genre |
Sea ice |
genre_facet |
Sea ice |
op_relation |
https://hdl.handle.net/1956/7079 |
op_rights |
Copyright the author. All rights reserved |
_version_ |
1766191460900667392 |