HR: 1330h
AN: OS43A-17    [Abstracts]
TI: Loop Current Ring Shedding: the Formation of Cyclones and the Effect of Topography.
AU: * Cherubin, L M
EM: lcherubin@rsmas.miami.edu
AF: University of Miami - RSMAS, 4600 Rickenbacker Causeway, Miami, FL 33149 United States
AU: Morel, Y
EM: morel@thor.cst.cnes.fr
AF: SHOM - CMO, 42, Avenue Gaspard Coriolis, Toulouse, 31057 France
AU: Chassignet, E P
EM: echassignet@rsmas.miami.edu
AF: University of Miami - RSMAS, 4600 Rickenbacker Causeway, Miami, FL 33149 United States
AB: The formation of cyclones in the vicinity of the LC ring during the shedding process is analyzed in terms of vortex instability. Using a high resolution ECMWF-daily wind forced MICOM simulation, we show that cyclones are the products of a mixed barotropic-baroclinic vortex instability, which grows around the rim of the LC ring while it is attached to the LC. Cyclones contributes to the separation of the ring from the LC as they grow between them. The QG instability of the LC-like type `R` vortex shows that a mode 4 baroclinic instability is intensified in the deep layers of the ring while barotropic instability is surface intensified. The nonlinear state shows that a LC-like vortex is indeed a pentapole on an f-plane. On the β-plane, the northern cyclone is separated from the anticyclone by the β-effect and both drift westward. When the topography of the GOM is taken into account, namely the Campeche Bank, the southward slope north of the LC and the Florida shelf east of the LC, several effects are observed: (1) the northern corner of the Campeche Bank erodes the LC ring and its cyclones, and interacts with the vortex most unstable mode; (2) the northern southward slope scatters the northern cyclone while the anticyclone remain coherent and propagate to the west; (3) realistic westward propagation speeds are obtained in the presence of the northern Campeche shelf, which acts as a mirror effect on the LC ring as opposed to the Florida shelf, which tends to block the ring.
DE: 4520 Eddies and mesoscale processes
SC: Ocean Sciences [OS]
MN: 2005 Joint Assembly