related to the strong negative temperature gradients observed between 73 and 135 m. A 

 small change in depth changes the temperatures considerably. For example, the temper- 

 ature difference of -0.47°C at 101 m can be accounted for by a depth change of about 3 m. 

 The second feature is that from the surface to 73 m and from 147 to 242 m, where the 

 temperature gradients are small, eight of the differences are negative and 23 are positive or 

 zero. The average difference for these two layers is 0.0 1°C. It is concluded that the 

 SUDS I thermistor chain system error is -0.0 1°C. 



TOWED THERMISTOR SYSTEM ERROR 



During the Gulf of Alaska experiments conducted at Al , A2, A3, and during both 

 environmental surveys, a towed thermistor sensor recorded surface temperatures. During 

 environmental survey 1 , Al , and A2, 61 STD/SV profiles were made. During environmental 

 survey 2 and A3, 22 SVTP profiles were made. In both series, simultaneous towed ther- 

 mistor measurements were recorded. These measurements provide the data needed to 

 determine the towed thermistor system error. 



Figure 10 is a histogram that compares the towed thermistor measurements with 

 the STD/SV (diagonal hnes) and SVTP (dotted) surface temperature measurements. 

 Shown, for 0.05°C temperature intervals, is the number of differences in the indicated 

 interval. The average difference for the STD/SV comparison was 0.08°C with a standard 

 deviation of 0.05°C; for the SVTP comparison, the average difference was -0.1 1°C with a 

 standard deviation of 0.08°C. Thus the towed thermistor system error shifted by 0.1 9°C 

 between the A2 and environmental survey 2 m.easurements. This could possibly be related 

 to a recalibration of the towed thermistor system between the A2 and the environmental 

 survey 2 measurements. At any rate, it is concluded that the towed thermistor system 

 error was -0.08°C during environmental survey 1 , Al , and A2, and 0.1 1°C during environ- 

 mental survey 2 and A3. 



31 



