SUMMARY AND CONCLUSIONS 



Time-dependent horizontal-temperature gradients were 

 computed from low-pass-filtered, continuous, temperature cross 

 sections of the upper 750 feet of the ocean in 17 widely separated 

 geographic areas . The selected areas range north to the Bering 

 Sea, south to the coastal waters of the Mexican mainland includ- 

 ing the Gulf of California, and west to the Hawaiian Islands. 



The horizontal-gradient fields, computed from smoothed 

 temperature structures, alternate in sign with a regularity that 

 implies a dominant frequency of internal waves or convection 

 cells. The wavelength is 0.72 nautical mile with a standard 

 deviation of 0. 16 mile. 



The vertical- and horizontal-temperature-gradient fields 

 contain zones of diverse intensity gradient. The vertical- 

 temperature gradient in the thermocline is generally of the order 

 10" 2 °C/ft, but ranges between 10 _1 and 10 " 3 °C/ft. The corre- 

 sponding horizontal-temperature gradient is generally of the 

 order 10 " 4 °C/ft, but ranges between 10 " 3 and 10 " 5 °C/ft. The 

 slopes of isothermal surfaces are of the order 10 "" . A statis- 

 tical analysis of the ratio of the horizontal to the vertical 

 temperature gradient shows that the horizontal gradient in the 

 thermocline can be predicted within useful limits from the meas- 

 ured vertical -temperature gradient by means of the equation 



dT/dx = 0.0047 (dT/<fa)°- 7 l 



The combined interrelationship of the vertical- and 

 horizontal -temperature gradients and the wavelength of the 

 dominant frequency of oscillation of the temperature structure 

 were used as the foundation for a simplified predictive model of 

 the horizontal-temperature gradients of the sea. The consistency 

 of the results over widely separated geographic areas leads to 

 the speculation that they are characteristic of the world ocean. 



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