

Temperature, 



°C 





Surface 



400 m 



XBT96 



19.65 







8.53 



XBT98 



17.63 







5.90 



Difference 



-2.02 







-2.63 



CTD/SV 19 



18.93 







6.35 



CTD/SV 20 



19.34 







6.11 



Difference 



+0.41 







-0.24 



Table 24. Comparison of the surface and 400-m 



temperatures for XBT 96 and 98 and 



CTD/SV 19 and 20. 



During RAPLOC/DEEPTOW, two 460-m systems - system A and system B - were 

 used. Bucket temperatures were obtained simultaneously with 40 system A XBT profiles 

 and with 31 system B XBT profiles. Pertinent statistics are summarized in table 25. On the 

 average, the surface temperatures measured by system A and system B were slightly higher 

 than those measured by the bucket thermometer. 





System A 



System B 



Number of comparisons 



40 



31 



Average difference, °C 



0.08 



0.01 



Standard deviation, °C 



0.14 



0.16 



Largest difference, °C 



0.37 



0.42 



Smallest difference, °C 



-0.30 



-0.35 



Table 25. Statistical summary for RAPLOC/DEEPTOW 

 surface temperature differences. 



SUMMARY 



Independent surface temperature measurements were made at the same time that 

 XBT profiles were made during the Gulf of Alaska, SUDS I, CAPER, and RAPLOC/ 

 DEEPTOW experiments. A few measurements were made with the hydrocast and STD/SV 

 systems. Most of the measurements used a towed thermistor (Gulf of Alaska), thermistor 

 chain (SUDS I), or bucket thermometers (CAPER and RAPLOC/DEEPTOW). The data 

 base is summarized in table 26. A total of 736 XBT profiles were made, together with one 

 or more independent and simultaneous surface temperature measurements. 



The purpose of these measurements was to check the surface temperature measure- 

 ment accuracy of visually acceptable XBT profiles. As the analysis proceeded, a secondary 

 purpose was realized. This was to use the independent measurements as detectors of 

 malfunctional XBT systems. 



59 



