A PRELIMINARY STUDY ON THE FRONTAL SECONDARY CIRCULATION IN ATMOSPHERE OVER CHINA

By using sawyer-shapiro's method, we have calculated the frontal secondary circulation characteristic of some local fronts in China. It is found that there exist four different basic patterns of frontal circulation in the mid-low troposphere over China: single cell pattern (positive or negative circulation), double cell pattern A (juxtaposed),double cell pattern B (superposed) and multiple cell pattern.We can explain in terms of the characteristics of frontal circulation why the warm front moves backward in North-East China.Over East China in summer, although the front is rather shallow, the top of frontal circulation is very high. Accordingly, heavy rain often appears near the front.