The example indicates the nature of vertical 

 oscillations in the thermal structure which are 

 commonly called internal waves. It is apparent 

 that the cycles in the vertical displacement of 

 the isotherms contain a wide spectrum of wave- 

 lengths . The longer and higher waves are found 

 where the vertical gradients are weaker, in this 

 case near the surface and at the greater depths 

 of 600 to 800 feet. In the main thermocline 

 where the isotherms are more compact, around 200 

 to 300 feet, wavelengths of 0.2 to 0.5 mile are 

 common hut not uniform. The heights of the larger 

 waves are about 20 feet in the thermocline, 

 whereas at the other depths they may be several 

 hundred feet. 



Most of these small waves on different iso- 

 therms in the thermocline are in phase with each 

 other; however, this is not necessarily true of 

 the larger waves above and below the thermocline. 

 In fact, around the 6 mile range the 1^ degree 

 and 18 degree isotherms are almost out of phase. 

 Another feature is the temperature inversions 

 that occur below the main thermocline in the 11 

 and 12 degree isotherms. This example clearly 

 shows the nature of sea water temperature struc- 

 ture recordings that can be obtained with the 

 thermistor chain system. 



CONCLUSIONS 



The USNEL towed sea temperature structure pro- 

 filer is a satisfactory device for measuring and 

 recording the thermal structure of the ocean. 

 This profiler has been very successful in record- 

 ing, for the first time, the details of the 

 thermal structure of the Pacific Ocean and the 

 nature of fronts and internal waves which cannot 

 be obtained by any other means at the present 

 time. 



REFERENCES 



1. LaFOND, E. C, Two-dimensional oceanography, 

 Bureau of Ships J. , 10 , 3-5, December 1961. 



2. RICHARDSON, W. S. and C. J. HUBBARD, The 

 contouring temperature recorder, Deep - Sea 

 Res ., 6, 239-2^, i960. 



3. COMMERCIAL ENGINEERING CORPORATION, Manual 

 for 900 foot oceanographic chain hoist no. k 

 Mk II-F chain, Publ. 2k, 1961. UNPUBLISHED. 



k. SCIENTIFIC SERVICE LABORATORIES, INC., 



Preliminary instruction and operation manual 

 for the contouring temperature recorder - 

 model 1, 30 June I96I. UNPUBLISHED. 



5- LaFOND, E. C, Slicks and temperature struc- 

 ture in the sea, Rept. 937, U. S. Navy 

 Electronics Lab., 2 November 1959- 

 UNPUBLISHED . 



59 



