CLEAVAGE OF A GULF-OF-MEXICO LOOP CURRENT EDDY BY A DEEP-WATER CYCLONE

Eddy Triton, an anticyclonic eddy shed by the Loop Current in late Jun e 1991, drifted SW across the central Gulf of Mexico in the first 6 mo nths of 1992, along the ''southern'' of the three characteristic drift paths described by Vukovich and Crissman [1986] from their analyses o f 13 years of advanced very high resolution radiometer sea surface tem perature data. An expendable bathythermograph (XBT) and conductivity-t emperature-depth (CTD) transect of opportunity through Triton at eddy age 7 months in January 1992 found that eddy interior stood 23 dyn. cm higher than periphery; this gradient drove an anticyclonic swirl tran sport of 9-10 Sv relative to 800 dbar. At eddy age 9-10 months and whi le this eddy was in deep water near 94 degrees W, it interacted with a mesoscale cyclonic circulation and was cleaved into two parts. The ma jor (greater dynamic centimeters) piece drifted NW to end up in the '' eddy graveyard'' in the NW corner of the gulf, while the minor piece d rifted SW and reached the continental margin of the western gulf off T uxpan. This southern piece of Eddy Triton then turned north to follow the 2000-m isobath to about 24 degrees N and later coalesced with what remained of the major fragment. Because Eddy Triton's cleavage took p lace just before the start of marine mammals (GulfCet) and Louisiana-T exas physical oceanography (LATEX) field programs, the closely spaced CTD, XBT, and air dropped XBT (AXBT) data that were gathered on the co ntinental margin north of 26 degrees N in support of these programs al low a detailed look at the northern margin of the larger fragment of t his eddy. Supporting data from the space-borne altimeters on ERS 1 and TOPEX/POSEIDON allow us to track both pieces of Eddy Triton in the we stern Gulf and follow their spin down in dynamic height, coalescence, and ultimate entrainment in January 1993 into another anticyclonic edd y (Eddy U).