THE APPLICATION OF THE ADVECTIVE-DYNAMIC ANALYSIS OF U.S.S.R.IN WEATHER FORECASTING IN EASTERN ASIA

In the last year,the application of the advective-dynamic analysis of U.S.S.R,.has made a definite contribution to the improvement of Chinese weather forecasting.From the last year experience it is found that this method is useful in the following three aspects; (1) judging the formation and development of frontal zone in the westerlies from the conditions in TP-field,(2)forecasting the formation and development of surface cyclone in IVZongolia and Northeast China,(3)forecasting the change of upper air pattern in high latitudes over East Asia.Owing to the less frequency of occurence of upper deformation field over the East Asia,the pressure systems encountered in this region are frequently movable.According to our experience the movement of pressure systems is usually regular,provided that there iswo blocking system downstream,that the areas of dynamical pressure rise and fall in TP-field are distributed symmetrically on both sides of the trough (or ridge) line,and that there are no indications of the deepening or filling of the trough (or ridge).Under these circumstances,it is comparatively successful to estimate the future position of upper pressure system by extrapolation.