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Mesoscale dynamics in the A rabian S ea and a focus on the G reat W hirl life cycle: A numerical investigation using ROMS
Author(s) -
Vic C.,
Roullet G.,
Carton X.,
Capet X.
Publication year - 2014
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2014jc009857
Subject(s) - mesoscale meteorology , rossby wave , anticyclone , climatology , vorticity , vortex , atmospheric sciences , geology , meteorology , physics
The Great Whirl (GW) is a persistent anticyclonic mesoscale eddy that is observed seasonally in the Arabian Sea during a period embedding the 3 months of the southwest monsoon (June–July–August) at a quasi‐steady location. Its dynamics remain unclear despite it being one of the largest coherent vortices in the world ocean. Realistic regional numerical experiments using ROMS are performed to investigate the life cycle of the GW, which is not well resolved by sparse available in situ measurements in the region. Using a set of sensitivity experiments and an accurate temporal characterization of the eddy properties (including position, radius, depth, and vorticity) we (i) confirm the role of basin‐scale downwelling Rossby waves in the GW generation, (ii) clarify the role of the monsoonal strong anticyclonic wind in its maintenance and barotropization, and (iii) suggest a connection between basin‐scale Rossby wave dynamics and GW collapse.