ABSTRACT 



A statistical study of errors associated with the bathythermograph 

 (BT) has been made from data obtained during eight 3-week cruises 

 to ocean weather stations (OWS) DELTA and ECHO. Simultaneous 

 observations using reversing thermometers, bucket thermometers, 

 and injection thermometers and nine sets of observations using two 

 connected BT's were analyzed. BT instrument bias varies with depth 

 as much as 1°F with maximum error occurring in the thermocline. 

 One pair of BT's recorded standard errors that varied from 0.20° to 

 0.61° F with depth and averaged 0.34° F. 



Mean differences between reversing thermometer reference tem- 

 peratures and BT, bucket, and injection thermometer temperatures 

 were computed. Comparison of these differences indicate that ship 

 injection thermometers averaged 1°F high; the BT's and bucket 

 thermometers recorded sea surface temperature with approximately 

 the same degree of accuracy, averaging within 0.5° F of the reference 

 temperature. 



At present, BT observations are processed by the National Oceano- 

 graphic Data Center without correcting for instrument bias. Compar- 

 isons between uncorrected data and data containing a temperature 

 correction factor (TCS) based on bucket thermometer readings 

 indicate that the correction factor increases the average accuracy of 

 th n nhc n Ki>-^t i r>r.> -fa^>'^ '■'- " '■ ^"'^'""^"'"'py js Small. Accuracy 



