OCEAN TEMPERATURE CHANGES INDUCED BY TROPICAL CYCLONE

Sea surface temperature (SST) decreases and mixed layer depth (MLD) increases occur in crescent-shaped patterns with respect to the moving storm center. The largest SST decreases occur in the right-rear quadrant of the storm at an average distance of 1.5 times the radius of maximum wind (RMAX). Storms moving slower than 3 m/s produce SST decreases of 3-5(DEGREES)C within one-half day of storm passage while faster moving storms produce only 1-3(DEGREES)C decreases. Very little change occurs in the left quadrant of the storm. The largest MLD increases of 24 m occur at 2.0 times RMAX to the right of the center. The largest MLD decreases of 12 m occur at 0.5 times RMAX.;The observations suggest that SST decreases continue at a location to the right of the storm track became larger for a period of 0.6 to 1.4 days after the storm forcing has moved away. A residual vertical circulation appears to be sustained for some time after storm passage which continues to transport colder water upward beneath the storm track and warmer water downward beyond two times RMAX to the right of the track.;Following the initial response, the residual SST and MLD patterns are modulated by an internal, inertia-gravity wave response. Wake patterns at larger distances and longer periods (two-to-five inertial periods) after the storm passage reflect scales of variation consistent with inertial wavelengths. For some intense storms, a transition region exists on the order of one-to-two inertial wavelengths, where a 100-200 km scale of variation in the SST and MLD patterns is most pronounced. It is speculated that this may be a harmonic of the longer inertial wavelength excited by finite amplitude effects due to the extreme magnitude of the forcing.;Temperature versus depth cross-sections normal to slow-moving storms, and at inertial wave crests in the wake of fast-moving storms, show that upward isotherm displacement occurs at the center of the track from the MLD to a depth of 150 m. At about two RMAX to the right of the storm, large subthermocline temperature increases are present to a depth of 100 m and are associated with MLD increases.;In large, slow-moving storms, SST decreases induced by a storm can cause a reduction in the sensible heat flux by up to a factor of four, and in latent heat flux by up to a factor of two. Inner core SST decreases of 2(DEGREES)C, or more, in 24 hours were correlated with filling rates of central pressure (PMIN) of 0.7 to 2.4 mb/hr for 6-24 hours in seven storms that were studied.