Seasonal Modulation of Eddy Kinetic Energy and Its Formation Mechanism in the Southeast Indian Ocean
Open Access
- 1 April 2011
- journal article
- Published by American Meteorological Society in Journal of Physical Oceanography
- Vol. 41 (4), 657-665
- https://doi.org/10.1175/2010jpo4436.1
Abstract
Mesoscale eddy activity in the southeast Indian Ocean (15°–30°S, 60°–110°E) is investigated based on available satellite altimetry observations. The observed sea level anomaly data show that this region is the only eastern basin among the global oceans where strong eddy activity exists. Furthermore, the eddy kinetic energy (EKE) level in this region displays a distinct seasonal cycle with the maximum in austral summer and minimum in austral winter. It is found that this seasonal modulation of EKE is mediated by baroclinic instability associated with the surface-intensified South Indian Countercurrent (SICC) and the underlying South Equatorial Current (SEC) system. In austral spring and summer the enhanced flux forcing of combined meridional Ekman and geostrophic convergence strengthens the upper-ocean meridional temperature gradient, intensifying the SICC front and its vertical velocity shear. Modulation of the vertical velocity shear results in the seasonal changes in the strength of baroclinic instability, leading to the seasonal EKE variations in the southeast Indian Ocean.Keywords
This publication has 31 references indexed in Scilit:
- Interannual variability of the Gulf of Alaska eddy fieldGeophysical Research Letters, 2007
- Eddy formation through the interaction between the Leeuwin Current, Leeuwin Undercurrent and topographyDeep Sea Research Part II: Topical Studies in Oceanography, 2007
- Dynamical Response of the Oceanic Eddy Field to the North Atlantic Oscillation: A Model–Data ComparisonJournal of Physical Oceanography, 2004
- Seasonal Modulations in the Eddy Field of the South Pacific OceanJournal of Physical Oceanography, 2004
- Annual and interannual variations of the Leeuwin Current at 32°SJournal of Geophysical Research: Oceans, 2003
- Seasonal variation and instability nature of the North Pacific Subtropical Countercurrent and the Hawaiian Lee CountercurrentJournal of Geophysical Research: Oceans, 2002
- Upstream control of Agulhas Ring sheddingJournal of Geophysical Research: Oceans, 2002
- Source of the baroclinic waves in the southeast Indian OceanJournal of Geophysical Research: Oceans, 2001
- Satellite altimeter monitoring the Kuroshio Transport south of JapanGeophysical Research Letters, 2001
- Variability in the southeast Indian Ocean from altimetry: Forcing mechanisms for the Leeuwin CurrentPublished by American Geophysical Union (AGU) ,1998