Ambrose Lightship (Figure 10, Table 10) 



The winter minimum, more than 2 F below the mean, occurred in late 

 February with a temperature of 35.6 F. Recovery had been made by April, at 

 which time the thermocline started to develop. There are no data for May 

 and part of June when the vessel was off station, but the record resumes 

 showing a cold summer with early cooling and temperatures well below the 

 mean. The summer maximum of 71.4 F occurred in early August. The passage 

 of hurrican Helena on 28 September weakened the thermocline by mixing, 

 but the gradient was not completely destroyed until the last decade in 

 October. At this time bottom temperature reached a maximum of 57.5 F. 

 Above normal air temperatures in November retard cooling. In December the 

 vessel was again off station. 



Salinities at the surface were similar to those of 1956 except that the 

 minimum of 24.65 /oo vjas considerably lower. The 1957 values were uniformly 

 above those for 1956 and 1958. 



SURFiCE T.-F 



J \ L 



JAN I FEB I MAR 



BOTTOM S%. 



SURFACE S%. 



Figure 10. Ambrose Lightship, 1958. (Dashed line in upper diagram, mean 

 for period 1937-1956) 



49 



