| Abstract: The Loop Current and the deep
circulation in the Gulf of Mexico are numerically investigated by a
primitive equation, sigma coordinate ocean model with realistic surface
fluxes obtained from an atmospheric forecast model. A deep cyclonic
circulation, bounded by the deep basin in the eastern Gulf of Mexico, is
spun up by the Loop Current; the deep cyclonic circulation is coincident
with a southward current of the Loop Current eastern limb and weakens
after Loop Current ring separation and cessation of the southward
current. The anticyclonic, semienclosed Loop Current also induces
anticyclonic lower layer columnar eddies in the eastern gulf. These
lower layer eddies decouple from the upper layer Loop Current. The
westward translation speed of a Loop Current ring is about 2.16–5.18
km d-1; the lower layer eddies have a higher speed and lead
the rings into the central gulf. The time-averaged surface circulation
of the Gulf of Mexico basin is anticyclonic, mainly because of the
transport of anticyclonic vorticity by Loop Current rings in the surface
layer an average lower layer cyclonic circulation occurs along the
continental slope of the basin. |