An ocean resonance in the Indian sector of the Southern Ocean

Abstract

Satellite altimeter observations of sea surface height show an extensive region of long wavelength fluctuations in the Indian sector of the Southern Ocean. A previous study showed that a similar feature found in the South Pacific is due to a trapped geostrophic mode of the ocean. Here we investigate the feature in the Indian sector and find that it is due to a similar mode with a decay time of approximately 3.5 days. These previously unsuspected large scale modes of the ocean will have a significant effect locally on the satellite based gravity measurements currently underway.