Diamond Shoals Lightship 



Temperature and salinity fluctuations from day to day are 

 extreme at this location, owing to the fact that the western edge of 

 the Florida Current tends to creep in over the shelf at this point. 

 Meanders in the current sweep toand fro across the position of the 

 lightship. 



One-third monthly means of surface tenperature indicate that 

 temperatures were lower 'during the first four mont>is of the year than 

 for the period 1923-56 except for the mid- and last-thirds ^f February, 

 Autumn temperatures were also below the record mean. In other words 

 coastal water tended to extend out across Diamond Shoals dui^ n,^ the 

 winter, early spring and autumn to a broader extent than indicated by 

 the averac;e for the period of record for these periods durin;; the year. 



Due to the large range in temoerature changes, the depth- 

 time profile of temperature is drawn with five decree isotherms, rather 

 than one degree isotherms as in the other figures. This figure may be 

 very misleading, however, because the sequence of encroachments of warm 

 saline water sweep in and out again with great rapidity. Further, the 

 penetrations of warm water may occur at the surface, mid-depth or bot- 

 tom. Averaging the data for ten^days at the other stations simplifies 

 the presentation without severely hiding the significant facts, but may 

 do so at this location. The reader, if interested in the phenomena at 

 Diamond Shoals would do well to draw his own plot from the tabulated 

 daily data. 



Surface temperatures ranged from kO - 85°F, bottom tempera- 

 tures from 1+2 to 79°F. 



Surface salinity ranged from 29.6°/oo to 36.3 /oo and bottom 

 salinity from 32.6%° to 36.Ii°/oo. 



101 



