Somali Current eddy interaction during the Indian Southwest Monsoon

Bryce A Melzer, Perspecta, Stennis Space Center, MS, United States, Tommy G Jensen, US Naval Research Laboratory, Ocean Sciences Division, Stennis Space Center, MS, United States, Adam Rydbeck, U.S. Naval Research Laboratory, Ocean Sciences, Stennis Space Center, MS, United States and Ebenezer Nyadjro, University of New Orleans, Stennis Space Center, MS, United States
Abstract:
Two representative southwest monsoon events are analyzed with regards to their contrasting patterns of intraseasonal variability in the region of the Somali current recirculation gyre. The year 2000 exhibited a strong intraseasonal oscillation on a period of 30 days, while the year 2002 exhibited a weak intraseasonal oscillation with a spectral peak of 60 days. HYCOM reanalysis is used to construct a vorticity budget, analyzing barotropic and baroclinic instabilities in the circulation which lead to periodic shedding of cyclonic eddies that orbit the Great Whirl gyre. A positive feedback mechanism is suggested in which these cyclonic eddies inject vorticity back into the boundary current, thus inducing the generation of subsequent eddies in the steady state solution. Additionally, anisotropy of the Great Whirl SSH signature may be a reasonable geometric proxy for the phase of such intraseasonal oscillations.
Back to: Toward an Improved Understanding of Indian Ocean Dynamics and Its Role in the Monsoon III Posters