Variability of eddy heat fluxes over the Northwestern Gulf of Mexico.
PhD Dissertation, Louisiana State University, Baton Rouge, LA, p. 81
Eddy heast flux variability over the Louisiana-Texas shelf was investigated using satellite-derived surface velocity and temperature data between October 1993 and October 1994. Assuming the product of sea water density and specific heat is relatively constant, velocity-temperature covariance reflects eddy heat flux (the fluctuating part of the 1x1 degree, 90 day mean heat flux). Available velocity and temperature fields, however, are not synchronous. Temperature "observations" at velocity position were optimally estimated using the Gauss Markoff Theorem. The error-estimate is comparable to the error resulting from the application of the widely accepted SST correction algorithm. The trend that instantaneous temperature flux principal axes become more isotropic offshore is significant at a = 0.10 in all season but October-December. Across the shelf, eddy heat flux is directed upcoast. In winter, the innershelf upcoast eddy is induced by cool downcoast transport associated with cold air outbreaks; while near the shelf break, it is induced by warm upcoast transport probably associated with an anticyclonic ring shed from the Loop Current. In the summer, the innershelf upcoast eddy heat flux is induced by warm upcoast transport. Eddy heat transport may be an important term in the winter heat budget. Heat is lost downcoast primarily because of the longshore mean-velocity gradient.