A modeling study of interannual variations of the Seychelles Dome

Interannual variations of the Seychelles Dome (SD) in the southwestern Indian Ocean are investigated using outputs from an ocean general circulation model. The high variability is locked seasonally to boreal winter. The SD becomes anomalously weak (strong) owing to anomalous local Ekman downwelling (upwelling) and arrival of downwelling (upwelling) Rossby waves excited in the southeastern Indian Ocean. In contrast to past studies, the anomalous local Ekman pumping cannot be neglected in discussing the interannual variability of the SD. In addition, the interannual variation of the SD is more closely linked with the Indian Ocean Dipole than El Niño–Southern Oscillation in the Pacific.