Accueil > Actualités > Séminaires > Séminaire de Yushi Morioka au LOCEAN


Titre : Remote and local impacts on the generation of the Indian Ocean Subtropical Dipole
Nom du conférencier : Yushi Morioka
Son affiliation : JAMSTEC / APL, Japan
Laboratoire organisateur : LOCEAN
Date et heure : 11-12-2014 17h30
Lieu : salle de réunion LOCEAN, tour 45/55, 4eme étage
Résumé :

Today we'll have two 30 minutes-long talks: The first one will be given by Pascal Oettli

Subtropical Dipole is an interannual climate phenomenon over the mid-latitude ocean basin in the Southern Hemisphere, which accompanies in its positive phase a warmer-than-normal sea surface temperature (SST) in the southwestern part of each basin and a colder-than-normal SST in the northeastern part. It develops during austral summer (December-February) in association with the variations in the subtropical high and causes the rainfall variations in the surrounding countries.
A series of coupled general circulation model (CGCM) experiments were performed to identify root causes of variations in the subtropical high during the Indian Ocean Subtropical Dipole (IOSD). The CGCM results show that even in the absence of the interannual SST variability in the tropics, the IOSD develops under the influence of high-latitude atmospheric variability, called the Antarctic Oscillation. Also, the local SST anomalies associated with the IOSD are found to contribute to the variations in the subtropical high by inducing the meridional SST gradient change and hence modulating the storm track activity in the troposphere. These results suggest that the local SST variability as well as the remote atmospheric influence is important for the variations in the subtropical high, which lead to the generation of the IOSD.