GEOGRAPHICAL AND SEASONAL VARIABILITY OF ROSSBY RADII IN SOUTH CHINA SEA

Abstract

On the basis of the 1 degree girded data of the seasonal mean temperature and salinity at standard levels in the South China Sea, mean Brunt Visl frequency profiles were derived in order to compute numerically the vertical normal mode for different seasons in various part of the South China Sea, and the associate linearized equation for horizontal large scale waves is solved numerically with a improved thompson Haskell algorithm. Therefore the baroclinic gravity wave phase speed C n and corresponding Rossby radius of deformation ( R n ) are obtained. Due to regional variations of stratification and the depth of the different basins, these parameters vary considerable, but the effect of temporal variation of the stratification can be neglected in the estimation of the first baroclinic gravity wave phase speed ( C 1 ) and Rossby radius of deformation ( R 1). It is shown that the geographical distribution of C 1 and R 1 provide a framework for a coherent understating of the dynamics of circulation, meso scale eddies and some boundary phenomena, such as boundary current, fronts, coastal upwelling, coastal traped waves and continental shelf waves, etc.