HR: 08:00h
AN: OS51D-01 INVITED     [Abstracts]
TI: Topographic Rossby Waves in the Gulf of Mexico
AU: * Hamilton, P
EM: phamilton@raleigh.saic.com
AB: Topographic Rossby waves (TRWs) have been investigated using arrays of current meter moorings and RAFOS drifters in three major regions of the deep Gulf of Mexico basin. They are the central northern Gulf, where the Sigsbee escarpment plays an important role in insulating the slope from energetic deep waves, around the northern and western sides of the Loop Current (LC) in the eastern basin, and over in the western Gulf, where fluctuations are much less energetic than further east. Ray tracing indicates that the western boundary of an extended LC is a likely generation region for TRWs. Further, the steep Sigsbee escarment tend to trap short (~ 10 day) period TRWs in the vicinity of 90W, and rectify longer period waves into a westward mean flow, manifested as a bottom trapped jet along the escarpment, in general agreement with recent theoretical models. Similar mechanisms appear to be important along the steep Mexican slope in the western Gulf. Lagrangian drifters deeper than 1500 m show generally rectilinear tracks that are compatible with propagating TRWs. There has been little evidence in these tracks of the existence of deep lower-layer eddies that are connected to, and translate with upper-layer LC anticyclones in some model simulations of the western basin of the Gulf. An overview of TRWs in the Gulf of Mexico basin, based primarily on extensive recent observations in the last 5 years, will discuss their characteristics, propagation, along with speculations on their generation and decay.
DE: 4512 Currents
DE: 4554 Planetary waves
DE: 4562 Topographic/bathymetric interactions
SC: Ocean Sciences [OS]
MN: 2007 Joint Assembly