EULERIAN AND LAGRANGIAN VELOCITY CORRELATIONS IN 2-DIMENSIONAL RANDOMGEOSTROPHIC FLOWS

Random flows in rotating fluid layers are studied in two spatial dimen sions. The Eulerian and Lagrangian correlation functions for such hows are analysed by approximating the actual two-dimensional flow by an a utonomous system consisting of many overlapping and mutually convectin g vortices. Analytical expressions for the full space-time-varying Eul erian velocity correlation are derived solely in terms of flow paramet ers. An extension of the arguments giving these results also allows th e derivation of analytical expressions for the Lagrangian velocity cor relation function. The analytical results are supported by a numerical simulation.