THE DISTRIBUTION OF E VECTOR ABOUT SUMMER LFO AND ITS RELATED TIME MEAN FLOW

By using observational data, the distribution of E vector is calculated and E vector with time mean flow is incorporated.The horizontal structure and propagation of 30-50 day periodic oscillation and its relation to the time mean flow a.re discussed. The result shows that the conversation of 1wo dimensional barotopic instability contributes to the devolepment of iow frequency fluctuation.