THE PROBLEM 



Investigate oceanographic factors pertinent to the behavior 

 of underwater sound and to surface and subsurface navigation. 

 Specifically, study the thermal structure of the upper sea layers 

 by use of a towed thermistor chain. 



RESULTS 



1. Detailed temperature structure data on the upper 800 

 feet of the sea south of Baja California, acquired by the U. S. Navy 

 Electronics Laboratory (NEL) Thermistor Chain, revealed vertical 

 and horizontal motion, large scale turbulence, and possible Doppler 

 effects. 



2. The sea temperature structure was found to vary widely 

 and may be characterized by (1) smooth thermoclines where the 

 isotherms had vertical oscillations with wavelengths generally 

 greater than 2400 feet; (2) normal thermoclines of varying wave- 

 length that averaged from 1400 to 2400 feet; (3) rough thermo- 

 clines with steep isotherms and most wavelengths of less than 

 1400 feet; and (4) irregular thermoclines of large vertical shifts 

 and major turbulent -type oscillations. 



3. Irregular thermoclines were found to be related to 

 fronts in water-mass boundaries caused by intermingling of the 

 Gulf of California Water with the California Coastal Current Water 

 and Eastern Tropical Pacific Water. 



4. The isotherm slopes, determined from over 65,000 data 

 samplings, showed a median of absolute values of vertical slope 

 to be 0°25', and the 70th percentile of absolute values of slope to 

 be 0°51'. The steepest isotherm slopes were found just south of 

 the peninsula of Baja California. 



5. The slopes were steeper during a tow to the north or 

 south, which implied that off southern Baja California and in the 

 mouth of the Gulf of California the wave crests in the thermocline 

 were oriented more in an east-west direction. 



6. The significant peaks in the power spectrum of isotherm 

 depth of encounter were so distributed at different frequencies that 

 no single frequency was dominant. 



