201 



cooler water indicated modified temperature structures where typical Gulf- 

 water salinities occurred. 



The influence of the hurricane was not restricted to the surface layers, 

 for there was an upward transport of heat from depths greater than 100 meters. 

 This was best exemplified by changes which took place in the vertical and 

 horizontal configuration of the thermocline. For Figures 7 and 8 , semi- 

 diagrammatic sketches were drawn from data gathered by thermistor- chain tows 

 along the tracks indicated in Figure 1. (it must be noted here that 

 Figures 7 and 8 were drawn from average values of the data obtained by the 

 the rmi 8 tor- chain. The temperatures and the depths of the isotherms differ to 

 some extent, therefore, from those plotted directly from the bathythermograms . ) 

 On August 23 there was a thermocline typical of these Gulf waters, exhibiting 

 a flat surface at depths of 65 to 70 meters. The thickness of the thermocline 

 decreased in an offshore direction, but the 26*^C isotherm remained as the 

 upper limit throughout the length of water measured. 



During the hurricane, 26 C water was carried into the disturbed surface 

 layer, and the 25°C isotherm marked the upper jjart of the thermocline on 

 September 15 ( Figure 8 ) , The surface of the thermocline was no longer flat, 

 having been depressed to the shoreward and seaward of the region where the 

 tracks of the hurricane and thermistor tow crossed. A comparison of the two 

 profiles ( Figures 7 and 8) reveals that after the storm the 2k° and 25°c 

 isotherms were deeper in the near-shore area and that those below the 

 thermocline were from I8 to 70 meters shallower than on August 25. The 

 greater upward displacement was in the deei)er water (note the 20°C isotherm, 

 for example) . 



The topography of the 25°C isotherm (top of the thermocline) during the 

 days of October ^+-9 closely resembled the configuration of the temperature 

 distribution. Whereas south of Galveston and seaward of the shelf break, 

 the thermoclinal surface was generally between 50 and 75 meters, to the west 

 it was depressed to depths of 102 meters ( Figure 9)- From the edge of the 

 shelf shoreward, the depth to the thermocline decreased abruptly, and, along 

 the track of the hurricane, it was absent in waters shoaler than 50 meters 

 (see Figure 2) . 



Authors ' Note ; A more complete paper was prepared for presentation at 

 the Third International Conference on Hurricanes and Tropical Meteorology 

 held in Mexico City in June 1963. That paper is now in press in Geofisica 

 Intemacional as part of the Conference proceedings. 



In presenting this condensed version at Wakulla Springs in February 

 1965, it was the authors' intent to show the similarities and differences 

 in the water temperature distribution in the northwest Gulf in 1961 as 

 compared with that existing after hurricane Hilda (see Leipper, this 

 volume ) . 



