Composite analyses of buoy and Coastal Marine Automated Network (C-MAN) observations from 34 Atlantic basin hurricanes over the 1975-1997 period illustrate that surface air temperatures (Ta) often cool 2-3K approximately 150-350 km from the TC center. Since this reduction in Ta initially occurs well outside the inner core (where horizontal pressure gradients are strongest), it is highly unlikely that this observed cooling is a direct result of adiabatic expansion. It also appears that a corresponding reduction in surface specific humidity (q) is observed over this same region. A possible explanation for these results may be that under certain circumstances, convective downdrafts near regions of active convection are acting to cool and dry the near-surface environment outside the TC inner core.
In an attempt to further test the apparent correlation between Ta and q, statistical analyses using all available paired observations of Ta and q from the multi-storm database will be conducted. In addition, Global Positioning System (GPS) dropwindsonde data obtained from the 1997 Hurricane Research Division (HRD) field program will be used to reconstruct the horizontal distribution of near-surface thermodynamic conditions for select 1997 TCs. Radar composites will also be generated for these storms in order to delineate areas of active precipitation. Key findings from the 34 TC composite research, results from the statistical investigation, and analyses from the 1997 GPS/Radar study will be presented