Role of Tropical SST Variability on the Formation of Subtropical Dipoles - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Climate Année : 2014

Role of Tropical SST Variability on the Formation of Subtropical Dipoles

Résumé

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-high latitudes, called the Antarctic Oscillation (AAO), becomes dominant and the stationary Rossby waves related to the AAO induce the 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.
Fichier principal
Vignette du fichier
jclim2014_morioka_etal.pdf (4.54 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Loading...

Dates et versions

hal-01086698 , version 1 (22-06-2016)

Identifiants

Citer

Yushi Morioka, Sébastien Masson, Pascal Terray, Chloé Prodhomme, Swadhin K. Behera, et al.. Role of Tropical SST Variability on the Formation of Subtropical Dipoles. Journal of Climate, 2014, 27 (12), pp.4486-4507. ⟨10.1175/JCLI-D-13-00506.1⟩. ⟨hal-01086698⟩
122 Consultations
106 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More