206 



layer, (2) the intensity of the storm and the consequent reaction of the 

 vater, or (3) a combination of both. 



Were the temperature decrease sufficient, in any water, to produce a 

 density instability, convective stirring must take place (in addition to 

 mechanical stirring by wave action). In such cases, inversions would be 

 eliminated and a thoroughly mixed layer formed (as noted by Leipper in 

 waters of normal salinity in the north- central C5ulf, and by the authors in 

 the waters southeast of Galveston) . If cooling were insufficient to cause a 

 convective stirring in the brackish surface water, but extended below the 

 low- salinity layer, a mixed zone below the inversions would be expected. 

 Hone was noted (see Figure 2). A more precise determination could be made 

 if there were adequate salinity data. However, in October I961, we obtained 

 too few salinity samples to analyze the depth distribution of the brackish 

 water in detail. Thus, we must rely on an interpretation of the temperature 

 data. 



The lesser salinity of the surface waters could, as mentioned, control 

 the magnitude of the temperature inversions. Again, should the cooling be 

 so great as to produce a density instability, convective mixing would result. 

 Conceivably, then, cooling could produce greater temperature differences than 

 observed in the inversions, but the depth and magnitude of the inversions 

 would be limited by the consequent instability of the water column. 



The temperature-salinity curve in Figure k'b shows that, the water to 

 150 meters (at this station) was far less stable than that normally encountered, 

 but still did not reach a neutral stability (a frequent condition in the Gulf 

 during the winter). The temperature decrease was not, therefore, the maximum 

 possible under the prevailing water conditions. It is clear, then, that the 

 depth and magnitude of the inversions were the result of the reaction of the 

 water to the storm. 



UPWELLING AND COOLING 



The discussion by Leipper of the water temperatures after hurricane 

 Hilda impressively described the mass transport of surface water from the 

 region underlying the "eye." Such a picture is not obvious from the data 

 obtained after hurricane Carla. Rather, the temperature inversions ascribe 

 to cooling of the water. 



Conversely, the temperature distribution after hurricane Hilda 

 presented great difficulties in defining a degree of heat loss from the 

 water. One cannot but presume that both mass transport and cooling take 

 place. However, to fit the two together from the available data is not a 

 simple matter, nor have we tried, other than by mental ruminations. 



Certainly, were one to place a magnitude of upwelling to the inversions 

 measured in 1961, then it is clear that cooling extended to a greater depth 



