15l^ 



the sea-surface temperature pattern. Computations of total energy flux 

 (sea to air) in the core of the Gulf Stream exceed I6OO g cal/cra day; yet 

 only a few miles seaward, approximately half of this value was obtained. The 

 maximum heat-exchange areas coincide with bsinds of warmer water, and minimum 

 heat-exchange areas coincide with bands of cooler water. 



The absolute values of sea-surface temperature and heat exchange undergo 

 a change upon the passage of a hurricane; however, the relationship between 

 temperature and heat exchange remains the same during the passage of a hur- 

 ricane . In the Gulf Stream, near the center of hurricane Ginny, calculations 

 of total heat exchange exceed 30OO g cal/cm day. 



Bathythermogram studies of the vertical temperature structure of the 

 ocean in the numerous water bands have indicated interesting relationships. 

 The warmer water bands, particularly the core of the Gulf Stream, are generally 

 isothermal to I5O-25O feet during this time of year (October); the cooler 

 water bands 'show a mixed layer of less than 50 feet. As the hurricane passes 

 over the cooler water, a notable decrease of the surface temperature can be 

 expected, while the deeper layers of isothermal water are less affected. It 

 could be concluded, therefore, that the surface temperature gradients do not 

 dissipate as is shown by Figure 6. The sea-surface temperature and hurricane 

 pressure curves indicate a unique relationship. 



HURRICANE GIMY 



Hurricane Ginny formed in the western Atlantic, in the vicinity of the 

 southeastern Bahamas, on October 16, 1963. In her formative stages, this 

 storm appeared to be extratropical in nature. Figures 3 sxid h represent the 

 surface weather chart and '^00-mb chart for 12 UT on October 19 . The available 

 data at 50O mb indicate the presence of a deep polar trough along the south- 

 east coast of the United States, with an apparent cold pool of air in its 

 axis . However, transformation of the cold core to a warm-core low had ap- 

 parently occurred by October 22 when the reconnaissance aircraft found that 

 the storm had acquired tropical characteristics . 



For study purposes, hurricane Ginny might be claKsified as an "ideal" 

 storm, primarily because of its erratic motion, slow movement, and the 

 coincidence of its track with the axis of the Gulf Stream. The "Yankee 

 Storm" in November 1935 followed a similar track. It developed in the 

 vicinity of Bermuda, moved westward to the vicinity of Cape -Hatteras, and 

 from there curved southwestward to the south coast of Florida. 



In this evaluation, the track of hurricane Ginny during October 22-28 

 is being studied (Figure 5). Hurricane positions indicated in Figure 5 were 

 obtained from the U. S. Weather Bureau radio teletjrpe summaries of reconnaissance 

 aircraft penetrating the eye of the storm. It is notable that a considerable 

 increase in the intensity of the storm occurred between October 2h, lij-00 UT, 

 and October 25, 0100 UT, when the eye of the hurricane entered the core of 

 the Gulf Stream. The increase in intensity was apparently due to the increase 



