Microstructure Analysis. Volume I. The Origin of Ocean Fine Structure
Final rept. 15 Feb-15 Aug 1975
PHYSICAL SCIENCES INC ANDOVER MA
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The horizontal and vertical length scales of ocean fine structure appear to correlate to the corresponding wavelengths of inertial waves internal waves whose motion is dominated by Coriolis forces. A priori, there are four possible non-linear mechanisms that could form ocean fine structure from inertial waves dynamic breaking shear instabilities, static breaking inverted density profile, transverse steepening resonance and longitudinal steepening self steepening of waves riding on their own velocity fields. Each mechanism was assessed. Of the four mechanisms proposed, dynamic wave breaking was shown to be the most probable mechanism by which inertial waves form fine structure. This mechanism is distinct from that of billow turbulence due to an unstable, horizontally propagating gravity wave. An inertial wave is a vertically propagating transverse wave. The transverse velocity field of the wave is a horizontal shear layer and it is the instability of the shear layer that is the proposed source of fine structure.
- Physical and Dynamic Oceanography