Thursday Seminar on nonlinear ocean eddies

TN Thursday Seminar on Markov Subsequences and Nonlinear Ocean Eddies, by Professor Roger M. Samelson, Oregon State University.

In this talk, a quantitative empirical connection is exhibited between a modified random-walk Markov model and the dynamics of observed, satellite-altimeter-tracked nonlinear ocean eddies.  

The ocean mesoscale may be loosely defined as variability on temporal scales of weeks to years and horizontal spatial scales of tens to hundreds of kilometers.  Ocean eddies are mesoscale vortex structures that can maintain their coherence for as long as several years.  

Twenty years of satellite altimeter measurements of sea surface height have recently enabled a global census of these mesoscale ocean eddies and their properties, including their life cycles from generation to dissipation.  It is shown that the statistics of these observed eddy amplitude life cycles are well described by the excursions of a damped random-walk model, which are found empirically to have a quasi-universal mean structure.  

A generalization of this stochastic amplitude model to a stochastic field model is outlined, and some remarks are made toward a dynamical rationalization of the stochastic field model. (Joint work with M. Schlax and D. Chelton, Oregon St Univ.)

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