Internal waves of tidal character

Abstract

Measurements of temperature and salinity at various depths in the ocean have shown the existence of periodic variations with the same periods as those of the tidal forces. It has been argued that these oscillations cannot be true internal waves generated by the tidal forces because the periods of free oscillations at internal discontinuities are much longer than those of the tidal forces so that the necessary resonance conditions would not seem satisfied. The argument is re‐examined here, and it is shown that because of the Earth's rotation, which had not been considered previously, the periods of long internal waves are much shorter and their velocities much larger than was assumed previously. Consequently the resonance conditions for oscillations at internal surfaces of discontinuity are much more favorable than was supposed heretofore. The effect of such internal waves on the turbulent processes in the interior of the fluid is discussed.