Horizon / Plein textes La base de ressources documentaires de l'IRD

IRD

 

Publications des scientifiques de l'IRD

de Coetlogon G., Leduc-Leballeur M., Meynadier R., Bastin S., Diakhate M., Eymard Laurence, Giordani H., Janicot Serge, Lazar Alban. (2014). Atmospheric response to sea-surface temperature in the eastern equatorial Atlantic at quasi-biweekly time-scales. Quarterly Journal of the Royal Meteorological Society, 140 (682), 1700-1714. ISSN 0035-9009

Accès réservé (Intranet IRD) Demander le PDF

Lien direct chez l'éditeur doi:10.1002/qj.2250

Titre
Atmospheric response to sea-surface temperature in the eastern equatorial Atlantic at quasi-biweekly time-scales
Année de publication2014
Type de documentArticle référencé dans le Web of Science WOS:000340364000023
Auteursde Coetlogon G., Leduc-Leballeur M., Meynadier R., Bastin S., Diakhate M., Eymard Laurence, Giordani H., Janicot Serge, Lazar Alban.
SourceQuarterly Journal of the Royal Meteorological Society, 2014, 140 (682), p. 1700-1714. ISSN 0035-9009
RésuméThe surface-wind response to sea-surface temperature (SST) and SST meridional gradient is investigated in the Gulf of Guinea by using daily observations and re-analyses in the 2000-2009 decade, with a focus on boreal spring and summer months (May to August), where quasi-biweekly fluctuations in the position of the northern front of the equatorial cold tongue induce quasi-biweekly equatorial SST anomalies. Following a large-scale wind acceleration (deceleration), an equatorial SST cold (warm) anomaly is created within a few days. In order to explain the local atmospheric response to this SST anomaly, the two following mechanisms are invoked: first, a colder (warmer) ocean decreases (increases) the vertical stability in the marine atmospheric boundary layer, which favours a weaker (stronger) surface wind; and second, a negative (positive) anomaly of SST meridional gradient induces a positive (negative) anomaly of the sea-level-pressure meridional gradient, which decelerates (accelerates) the surface wind. The first mechanism has an immediate effect in the equatorial belt between 1 degrees S and 1 degrees N (and to a lesser extent between 3 degrees S and 1 degrees S), whereas the second takes 1 or 2 days to adjust and damps anomalous southeasterlies up to 800 hPa in the low troposphere between 7 degrees S and 1 degrees N, through reversed anomalies of meridional SST and pressure gradient. This negative feedback leads to weaker (stronger) winds in the southeastern tropical Atlantic, which forces the opposite phase of the oscillation within about 1 week. Around the Equator, where the amplitude of the oscillation is found to be maximal, both mechanisms combine to maximize the wind response to the front fluctuations. Between the Equator and the coast, a low-level secondary atmospheric circulation takes control of the surface-wind acceleration or deceleration around 3 degrees N, which reduces the influence of the SST-front fluctuations.
Plan de classementLimnologie physique / Océanographie physique [032]
Descr. géo.ATLANTIQUE ; ZONE EQUATORIALE
LocalisationFonds IRD [F B010062472]
Identifiant IRDfdi:010062472
Lien permanenthttp://www.documentation.ird.fr/hor/fdi:010062472

Export des données

Disponibilité des documents

Télechargment fichier PDF téléchargeable

Lien sur le Web lien chez l'éditeur

Accès réservé en accès réservé

HAL en libre accès sur HAL


Accès aux documents originaux :

Le FDI est labellisé CollEx

Accès direct

Bureau du chercheur

Site de la documentation

Espace intranet IST (accès réservé)

Suivi des publications IRD (accès réservé)

Mentions légales

Services Horizon

Poser une question

Consulter l'aide en ligne

Déposer une publication (accès réservé)

S'abonner au flux RSS

Voir les tableaux chronologiques et thématiques

Centres de documentation

Bondy

Montpellier (centre IRD)

Montpellier (MSE)

Cayenne

Nouméa

Papeete

Abidjan

Dakar

Niamey

Ouagadougou

Tunis

La Paz

Quito