VERIFICATION OF INTERNAL WAVES IN OFFSHORE AREAS BY MEANS OF CURRENT OBSERVATIONS

Based on the shear effect of internal wave currents in stratified fluid,the necessary condition for the possible existence of an internal wave and the sufficient condition under which there will be no internal wave are deduced starting from the continuity equation of incompressible fluid.The above two conditions are verified by the measured results from vertical current meter arraies at some observation stations in the Bohai Sea and the South Huanghai Sea.In the treatment of measured results,first of all,the tidal period components are separated from the measured currents by Fourier-analysis method,and then the internal wave currents of tidal period from the tidal period components in the light of some considerations.The analytical results of observed currents are well consistent with theoretical analysis.Furthermore,one can also deduce some features of internal waves therefrom.Consequently,it is concluded that the observation from a vertical current meter array is an important means to verify internal waves in offshore areas.