Some additional observations, based on the data of appendix H and table 44, are 

 of interest: 



1. The ORB-3 differences for 26 (57.8%) of the 45 pairs were less than or equal to 

 ±0.34°C at all above- and below-thermocline depths, and for the RAPLOC/DEEPTOW 

 differences the comparable number was 36 (80.0%) of the 45 pairs. For the combined 

 data set of 90 XBT pairs, 62 (68.9%) of the pairs had differences less than or equal to 

 ±0.34°C at all above- and below-thermocline depths. For the remaining 28 (31 .1%) of the 

 pairs, the differences were greater than ±0.34°C at one or more depths. 



2. For the combined data set of 90 pairs, the differences were all less than or equal 

 to ±0.34°C in the near-surface layer for 79 (87.8%) of the pairs, in the thermocline for 46 

 (5 1 .7%) of the pairs, and below thermocline for 61 (7 1 .8%) of the pairs. 



3. For the combined data set of 90 pairs, the differences at all comparison depths 

 were less than or equal to ±0.34°C for 43 (47.8%) of the pairs. 



4. For the 45 ORB-3 profiles, the layer depth differences were less than ±5 m for 

 40 (88.9%) of the pairs, and for the 45 RAPLOC/DEEPTOW profiles, the comparable 

 number was 41 (91 .1%) of the pairs. For the combined data set of 90 pairs, the near-surface 

 layer depth differences were less than or equal to ±5 m for 8 1 (90.0%) of the pairs and 

 exceeded ±5 m for nine (10.0%) of the pairs. 



Figure 42 is an ogive of the absolute value of the 1116 simultaneous XBT temper- 

 ature differences measured at standard hydrocast depths from the surface to 400 m during 

 the ORB-3 and RAPLOC/DEEPTOW experiments. The absolute value is used since the 

 signs of the differences are arbitrary. This figure shows the percentage of the 1116 compar- 

 isons of simultaneous XBT measurements that exceeded a given difference. For example, 

 16.6% exceeded 0.34°C. 



The preceding discussion was concerned primarily with the statistics of the 

 differences between simultaneous pairs of XBT profiles. The following discussion presents 

 and considers selected specific pairs of profiles, and supports the previous discussion. 



An inspection of the ORB-3 data listed in appendix H shows that for XBT pair 47, 

 the differences were greater than 0.34°C at all depths except the surface and 400 m, and for 

 XBT pair 12 they were greater than 0.48°C at all depths except the surface. For these two 

 comparisons, system A recorded a higher temperature than system B. Figure 43 shows 

 superimposed temperature profiles for these two comparisons. Note the large differences 

 in the near-surface layer where the temperature is nearly isothermal. In each case at least 

 one of the profiles must be incorrect. 



Average below-thermochne differences were greater than or equal to ±0.50°C for 

 four XBT pairs-XBT pair 46 (-1 .05°C), XBT pair 54 (-0.58°C), XBT pair 1 2 (0.54°C), 

 XBT pair 47 (0.50°C). XBT pairs 46 and 54 are presented in figure 44. These pairs show 

 how near identical agreement from 40 to 1 60 m for XBT pair 46 and from the surface to 1 90 m 

 for XBT pair 54. However, for depths greater than 160 m and 190 m, respectively, the 

 differences increase to as much as -1 .74°C at 400 m for XBT pair 46 and -0.84°C at 400 m 

 for XBT pair 54. In the figure 44 comparisons, system B measured temperatures higher 

 than system A. 



An inspection of the RAPLOC /DEEPTOW comparisons listed in appendix H shows 

 that some of the largest below-thermocline differences are associated with pairs 33 and 38, 

 which are presented in figure 45. Pair 33 shows minor differences in the near-surface 



106 



