Mixing, Convection, and Advection in the Upper Ocean.
FLORIDA STATE UNIV TALLAHASSEE MESOSCALE AIR-SEA INTERACTION GROUP
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Convection, mixing and advection in the upper ocean may be thought of as the motion of two interacting fluids of different properties the sinking fluid parcels generated near the surface and transmitting surface information downward, and the compensating rising return flow. A general theory based on this concept is developed and applied to various cases, including deepening of the wind-mixed layer, penetrative convection due to surface cooling, and upper ocean frontogenesis due to horizontal advection. Although the applications focus on the upper ocean, the theory also applies to the lower atmosphere. Equations of the general theory are written for two interactnig Boussinesq fluids in a rotating frame. Interaction terms are parameterized in order to apply the theory to geophysical situations. Considerable simplification is obtained by assuming that the response time of turbulence is much less than the time scale of evolution of the overall system. The study of deepening of the wind-mixed layer and of penetrative convection due to surface cooling are straightforward applications of the general theory. The analytical treatment of the equations is simplified using the observations that the mixed layer is quasi-homogeneous in its physical properties and that the thermocline is a thin layer of large gradients. The solution is analytical and simple.
- Physical and Dynamic Oceanography