Relationships between South Atlantic SST Variability and Atmospheric Circulation over the South African Region during Austral WinterSource: Journal of Climate:;2005:;volume( 018 ):;issue: 016::page 3339DOI: 10.1175/JCLI3474.1Publisher: American Meteorological Society
Abstract: The Southwestern Cape (SWC) region of South Africa is characterized by winter rainfall brought mainly via cold fronts and by substantial interannual variability. Previous work has found evidence that the interannual variability in SWC winter rainfall may be related to sea surface temperature (SST) in the South Atlantic Ocean and to large-scale ocean?atmosphere interaction in this region. During wet winters, SST tends to be anomalously warm (cool) in the southwest Atlantic and southeast Atlantic (central South Atlantic). Atmospheric general circulation model experiments with various idealized SST anomalies in the South Atlantic are used to explore mechanisms potentially associated with the rainfall variability. The model results suggest that the atmosphere is sensitive to subtropical?midlatitude SST anomalies in the South Atlantic during winter. Locally, there are changes to the jet position and strength, low-level relative vorticity, and convergence of moisture and latent heat flux that lead to changes in rainfall over the SWC. The model response to the SST forcing also shows large-scale anomalies in the midlatitude Southern Hemisphere circulation, namely, an Antarctic Oscillation?type mode and wavenumber-3 changes, similar to those observed during anomalous winters in the region.
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contributor author | Reason, C. J. C. | |
contributor author | Jagadheesha, D. | |
date accessioned | 2017-06-09T17:00:54Z | |
date available | 2017-06-09T17:00:54Z | |
date copyright | 2005/08/01 | |
date issued | 2005 | |
identifier issn | 0894-8755 | |
identifier other | ams-77951.pdf | |
identifier uri | http://onlinelibrary.yabesh.ir/handle/yetl/4220565 | |
description abstract | The Southwestern Cape (SWC) region of South Africa is characterized by winter rainfall brought mainly via cold fronts and by substantial interannual variability. Previous work has found evidence that the interannual variability in SWC winter rainfall may be related to sea surface temperature (SST) in the South Atlantic Ocean and to large-scale ocean?atmosphere interaction in this region. During wet winters, SST tends to be anomalously warm (cool) in the southwest Atlantic and southeast Atlantic (central South Atlantic). Atmospheric general circulation model experiments with various idealized SST anomalies in the South Atlantic are used to explore mechanisms potentially associated with the rainfall variability. The model results suggest that the atmosphere is sensitive to subtropical?midlatitude SST anomalies in the South Atlantic during winter. Locally, there are changes to the jet position and strength, low-level relative vorticity, and convergence of moisture and latent heat flux that lead to changes in rainfall over the SWC. The model response to the SST forcing also shows large-scale anomalies in the midlatitude Southern Hemisphere circulation, namely, an Antarctic Oscillation?type mode and wavenumber-3 changes, similar to those observed during anomalous winters in the region. | |
publisher | American Meteorological Society | |
title | Relationships between South Atlantic SST Variability and Atmospheric Circulation over the South African Region during Austral Winter | |
type | Journal Paper | |
journal volume | 18 | |
journal issue | 16 | |
journal title | Journal of Climate | |
identifier doi | 10.1175/JCLI3474.1 | |
journal fristpage | 3339 | |
journal lastpage | 3355 | |
tree | Journal of Climate:;2005:;volume( 018 ):;issue: 016 | |
contenttype | Fulltext |