PROBLEM 



Investigate and report on the nature of internal waves in the sea. 

 Specifically, study the differences between spectra of internal waves as 

 obtained from an anchor station and those measured by a towed thermistor 

 chain, and apply the results to internal tides in the sea off southern 

 California. 



RESULTS 



1. A method accounting for doppler-shift effects was used to interpret 

 data recorded from San Diego to Hawaii by moving thermistors. The 

 results lead to a reasonable picture of the internal tides in that area of 

 the Pacific Ocean. 



2. It is shown that internal waves can be produced directly by the tide- 

 generating forces. Free diurnal internal waves vanish at 30°N. 



3. Internal tidal waves are an important component in the spectra at tidal 

 frequencies in the sea off southern California. It is likely that they travel 

 in a northeasterly direction. 



RECOMMENDATIONS 



1. Verify the theory of internal waves of tidal period with additional 

 measurements with the thermistor chain. 



2. For a complete analysis of the various modes of internal waves, ex- 

 tend measurement of the thermal structure to the sea floor. 



3. Supplement the study of internal waves by the use of current meters 

 and salinometers mounted on the chain or at anchored stations; use the 

 data produced to increase the usefulness of thermistor-chain data in the 

 study of the ocean structure (sound-velocity structure) controlled by non- 

 periodic motion such as advection. 



5^^ ADMINISTRATIVE INFORMATION 



Work was performed under SR 104 03 01, Task 0580 (NEL L40461). 

 The report covers work from August 1963 to February 1964 and was 

 approved for publication 6 July 1966. 



