45 



90 135 180 225 270 



AVERAGE DIRECTION OF TOW (DEGREES) 



315 



Figure 7 9. Direction of tow vs overage median vertical isotherm angle derived from 

 differences in depth between the half-minute or 304-foot-spaced depth readings- Curve 

 represents isotherm slopes averaged by 45-degree groupings. 



(A) Upper: 70th percentile of absolute value of isotherm slope in thi 

 Sample values in solid points. 



(B) Lower: 50th percentile of absolute value of isotherm slope in th 

 Sample values in open points. 



ain thermocline. 

 tain thermocline. 



the 50th percentile and for the 70th percentile (fig. 19). Although 

 considerable variability in the changes in the vertical angle was 

 shown in both the 50th and 70th absolute -value percentile slope, the 

 50th absolute -value percentile values in the shallow isotherm have 

 a higher average when the towing is to the north or southwest. 

 This would imply that the vertical wave crest structures in shal- 

 lower parts of the thermocline were oriented more to the east and 

 west. 



42 



