Role of tropical SST variability on the formation of subtropical dipoles
Interannual variations of sea surface temperature (SST) in the midlatitudes of the Southern Hemisphere play an important role in the rainfall variability over the surrounding countries by modulating synoptic-scale atmospheric disturbances. These are frequently associated with a northeast southwest-o...
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ftird:oai:ird.fr:fdi:010062284 2023-05-15T13:55:14+02:00 Role of tropical SST variability on the formation of subtropical dipoles Morioka, Y. Masson, S. Terray, Pascal Prodhomme, C. Behera, S. K. Masumoto, Y. ATLANTIQUE SUD PACIFIQUE SUD OCEAN INDIEN SUD 2014 http://www.documentation.ird.fr/hor/fdi:010062284 EN eng http://www.documentation.ird.fr/hor/fdi:010062284 oai:ird.fr:fdi:010062284 Morioka Y., Masson S., Terray Pascal, Prodhomme C., Behera S. K., Masumoto Y. Role of tropical SST variability on the formation of subtropical dipoles. Journal of Climate, 2014, 27 (12), p. 4486-4507. text 2014 ftird 2020-08-21T06:53:34Z Interannual variations of sea surface temperature (SST) in the midlatitudes of the Southern Hemisphere play an important role in the rainfall variability over the surrounding countries by modulating synoptic-scale atmospheric disturbances. These are frequently associated with a northeast southwest-oriented dipole of positive and negative SST anomalies in each oceanic basin, referred to as a subtropical dipole. This study investigates the role of tropical SST variability on the generation of subtropical dipoles by conducting SST-nudging experiments using a coupled general circulation model. In the experiments where the simulated SST in each tropical basin is nudged to the climatology of the observed SST, the subtropical dipoles tend to occur as frequently as the case in which the simulated SST is allowed to freely interact with the atmosphere. It is found that without the tropical SST variability, the zonally elongated atmospheric mode in the mid- to high latitudes, called the Antarctic Oscillation (AAO), becomes dominant and the stationary Rossby waves related to the AAO induce the sea level pressure (SLP) anomalies in the midlatitudes, which, in turn, generate the subtropical dipoles. These results suggest that the tropical SST variability may not be necessary for generating the subtropical dipoles, and hence provide a useful insight into the important role of the AAO in the midlatitude climate variability. Text Antarc* Antarctic IRD (Institute de recherche pour le développement): Horizon Antarctic The Antarctic |
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IRD (Institute de recherche pour le développement): Horizon |
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Interannual variations of sea surface temperature (SST) in the midlatitudes of the Southern Hemisphere play an important role in the rainfall variability over the surrounding countries by modulating synoptic-scale atmospheric disturbances. These are frequently associated with a northeast southwest-oriented dipole of positive and negative SST anomalies in each oceanic basin, referred to as a subtropical dipole. This study investigates the role of tropical SST variability on the generation of subtropical dipoles by conducting SST-nudging experiments using a coupled general circulation model. In the experiments where the simulated SST in each tropical basin is nudged to the climatology of the observed SST, the subtropical dipoles tend to occur as frequently as the case in which the simulated SST is allowed to freely interact with the atmosphere. It is found that without the tropical SST variability, the zonally elongated atmospheric mode in the mid- to high latitudes, called the Antarctic Oscillation (AAO), becomes dominant and the stationary Rossby waves related to the AAO induce the sea level pressure (SLP) anomalies in the midlatitudes, which, in turn, generate the subtropical dipoles. These results suggest that the tropical SST variability may not be necessary for generating the subtropical dipoles, and hence provide a useful insight into the important role of the AAO in the midlatitude climate variability. |
format |
Text |
author |
Morioka, Y. Masson, S. Terray, Pascal Prodhomme, C. Behera, S. K. Masumoto, Y. |
spellingShingle |
Morioka, Y. Masson, S. Terray, Pascal Prodhomme, C. Behera, S. K. Masumoto, Y. Role of tropical SST variability on the formation of subtropical dipoles |
author_facet |
Morioka, Y. Masson, S. Terray, Pascal Prodhomme, C. Behera, S. K. Masumoto, Y. |
author_sort |
Morioka, Y. |
title |
Role of tropical SST variability on the formation of subtropical dipoles |
title_short |
Role of tropical SST variability on the formation of subtropical dipoles |
title_full |
Role of tropical SST variability on the formation of subtropical dipoles |
title_fullStr |
Role of tropical SST variability on the formation of subtropical dipoles |
title_full_unstemmed |
Role of tropical SST variability on the formation of subtropical dipoles |
title_sort |
role of tropical sst variability on the formation of subtropical dipoles |
publishDate |
2014 |
url |
http://www.documentation.ird.fr/hor/fdi:010062284 |
op_coverage |
ATLANTIQUE SUD PACIFIQUE SUD OCEAN INDIEN SUD |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic |
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Antarc* Antarctic |
op_relation |
http://www.documentation.ird.fr/hor/fdi:010062284 oai:ird.fr:fdi:010062284 Morioka Y., Masson S., Terray Pascal, Prodhomme C., Behera S. K., Masumoto Y. Role of tropical SST variability on the formation of subtropical dipoles. Journal of Climate, 2014, 27 (12), p. 4486-4507. |
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