华南东移中尺度系统的初步探讨

A PRELIMINARY INVESTIGATION OF EASTWARD TRAVELLING MESOSCALE SYSTEMS IN SOUTH CHINA

摘要:

根据乐昌和广州二处边界层逐时纬向风的资料作出的频谱图,估算出华南中尺度α的空间尺度为200—600公里。按此标准普查了1981—1985年3—6月的东亚天气图、华南高空风资料和日本GMS分析云图,发现存在二类主要的东移中尺度α系统:华南极锋中尺度波动和西南风低空急流大风核。应用常规的天气资料,对这二类中尺度系统进行了气侯学和天气学的探讨,得到了一些基本的认识。

Abstract:

From hourly zonal winds of the boundary layer in Lechang and Guangzhou, a frequency spectra diagram is worked out. According to it, the spacial scale of mesoscale a is estimated to be 200- 600km. The value is applied in statistical studies of Mar. -Jun. weather maps for East Asia (1981-1985), upper air soundings for the south of China and analyzed GMS cloud images of Japan. It is found that there are 2 types of prominent eastward travelling mesoscale a systems in southern China; mesoscale waves in polar fronts and gale cores in low-level SW jets. Conventional data are used to study the climatological and synoptic features of these mesoscale systems and a number of basic findings are obtained.