Intraseasonal variability of tropical Atlantic sea-surface temperature : air-sea interaction over upwelling fronts
Tropical Atlantic sea-surface temperatures (SSTs) maximum intraseasonal variability (ISV) and their interaction with local surface winds are investigated, applying statistical analysis to observations and to a recent coupled reanalysis over the 2000-2009 decade. Five cores of strong ISV emerge, with...
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ftird:oai:ird.fr:fdi:010066218 2023-05-15T13:55:17+02:00 Intraseasonal variability of tropical Atlantic sea-surface temperature : air-sea interaction over upwelling fronts Diakhate, M. de Coetlogon, G. Lazar, Alban Wade, M. Gaye, A. T. ATLANTIQUE SENEGAL MAURITANIE ANGOLA NAMIBIE ZONE TROPICALE 2016 http://www.documentation.ird.fr/hor/fdi:010066218 EN eng http://www.documentation.ird.fr/hor/fdi:010066218 oai:ird.fr:fdi:010066218 Diakhate M., de Coetlogon G., Lazar Alban, Wade M., Gaye A. T. Intraseasonal variability of tropical Atlantic sea-surface temperature : air-sea interaction over upwelling fronts. Quarterly Journal of the Royal Meteorological Society, 2016, 142 (694), p. 372-386. tropical Atlantic intraseasonal variability air-sea interaction text 2016 ftird 2020-08-21T06:51:54Z Tropical Atlantic sea-surface temperatures (SSTs) maximum intraseasonal variability (ISV) and their interaction with local surface winds are investigated, applying statistical analysis to observations and to a recent coupled reanalysis over the 2000-2009 decade. Five cores of strong ISV emerge, with standard deviation reaching about 1 degrees C in frontal areas of the three main upwelling systems: equatorial, Angola-Benguela and Senegal-Mauritania (the southern side of the Canary upwelling). West of 10 degrees W along the Equator, a 20-60-day peak caused by tropical instability waves is shown to generate surface wind anomalies through the adjustment of the horizontal surface pressure gradient in addition to the modification of near-surface atmospheric stratification. East of 10 degrees W along the Equator, an intense biweekly oscillation increases the ocean and atmosphere ISV. In the two coastal upwelling fronts, intraseasonal SST anomalies resemble each other. They are shown to be influenced by coastal Kelvin waves in addition to large-scale wind forcing. Over the Angola-Benguela upwelling, coastal wind bursts controlling the SST ISV are associated with anomalously strong pressure patterns related to the Madden-Julian Oscillation, the St Helena anticyclone and the Antarctic Oscillation. In the Senegal-Mauritania upwelling, the wind anomalies mainly linked to the Azores anticyclone in the southern front during November to May appear to be connected to the Saharan heat-low in the northern front from June to September. In all five regions and as expected for such upwelling regimes, vertical oceanic mixing represents the dominant term in the mixed-layer heat budget. In the equatorial band, as found in previous studies, horizontal advection is equally important, while it appears surprisingly weak in coastal fronts. Finally, a striking result is the general lack of surface wind signal related to the SST ISV in the coastal upwellings. Text Antarc* Antarctic IRD (Institute de recherche pour le développement): Horizon Antarctic The Antarctic St. Helena ENVELOPE(8.575,8.575,63.621,63.621) |
institution |
Open Polar |
collection |
IRD (Institute de recherche pour le développement): Horizon |
op_collection_id |
ftird |
language |
English |
topic |
tropical Atlantic intraseasonal variability air-sea interaction |
spellingShingle |
tropical Atlantic intraseasonal variability air-sea interaction Diakhate, M. de Coetlogon, G. Lazar, Alban Wade, M. Gaye, A. T. Intraseasonal variability of tropical Atlantic sea-surface temperature : air-sea interaction over upwelling fronts |
topic_facet |
tropical Atlantic intraseasonal variability air-sea interaction |
description |
Tropical Atlantic sea-surface temperatures (SSTs) maximum intraseasonal variability (ISV) and their interaction with local surface winds are investigated, applying statistical analysis to observations and to a recent coupled reanalysis over the 2000-2009 decade. Five cores of strong ISV emerge, with standard deviation reaching about 1 degrees C in frontal areas of the three main upwelling systems: equatorial, Angola-Benguela and Senegal-Mauritania (the southern side of the Canary upwelling). West of 10 degrees W along the Equator, a 20-60-day peak caused by tropical instability waves is shown to generate surface wind anomalies through the adjustment of the horizontal surface pressure gradient in addition to the modification of near-surface atmospheric stratification. East of 10 degrees W along the Equator, an intense biweekly oscillation increases the ocean and atmosphere ISV. In the two coastal upwelling fronts, intraseasonal SST anomalies resemble each other. They are shown to be influenced by coastal Kelvin waves in addition to large-scale wind forcing. Over the Angola-Benguela upwelling, coastal wind bursts controlling the SST ISV are associated with anomalously strong pressure patterns related to the Madden-Julian Oscillation, the St Helena anticyclone and the Antarctic Oscillation. In the Senegal-Mauritania upwelling, the wind anomalies mainly linked to the Azores anticyclone in the southern front during November to May appear to be connected to the Saharan heat-low in the northern front from June to September. In all five regions and as expected for such upwelling regimes, vertical oceanic mixing represents the dominant term in the mixed-layer heat budget. In the equatorial band, as found in previous studies, horizontal advection is equally important, while it appears surprisingly weak in coastal fronts. Finally, a striking result is the general lack of surface wind signal related to the SST ISV in the coastal upwellings. |
format |
Text |
author |
Diakhate, M. de Coetlogon, G. Lazar, Alban Wade, M. Gaye, A. T. |
author_facet |
Diakhate, M. de Coetlogon, G. Lazar, Alban Wade, M. Gaye, A. T. |
author_sort |
Diakhate, M. |
title |
Intraseasonal variability of tropical Atlantic sea-surface temperature : air-sea interaction over upwelling fronts |
title_short |
Intraseasonal variability of tropical Atlantic sea-surface temperature : air-sea interaction over upwelling fronts |
title_full |
Intraseasonal variability of tropical Atlantic sea-surface temperature : air-sea interaction over upwelling fronts |
title_fullStr |
Intraseasonal variability of tropical Atlantic sea-surface temperature : air-sea interaction over upwelling fronts |
title_full_unstemmed |
Intraseasonal variability of tropical Atlantic sea-surface temperature : air-sea interaction over upwelling fronts |
title_sort |
intraseasonal variability of tropical atlantic sea-surface temperature : air-sea interaction over upwelling fronts |
publishDate |
2016 |
url |
http://www.documentation.ird.fr/hor/fdi:010066218 |
op_coverage |
ATLANTIQUE SENEGAL MAURITANIE ANGOLA NAMIBIE ZONE TROPICALE |
long_lat |
ENVELOPE(8.575,8.575,63.621,63.621) |
geographic |
Antarctic The Antarctic St. Helena |
geographic_facet |
Antarctic The Antarctic St. Helena |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_relation |
http://www.documentation.ird.fr/hor/fdi:010066218 oai:ird.fr:fdi:010066218 Diakhate M., de Coetlogon G., Lazar Alban, Wade M., Gaye A. T. Intraseasonal variability of tropical Atlantic sea-surface temperature : air-sea interaction over upwelling fronts. Quarterly Journal of the Royal Meteorological Society, 2016, 142 (694), p. 372-386. |
_version_ |
1766261653572157440 |