东亚冷空气爆发后陆地变性的物理过程研究

本文对1981年不同月份8次东亚冷空气活动的陆地变性过程进行了分析。首先,用相似理论方法,直接计算了地面的感热和潜热的湍流交换及拖曳系数,又利用收支法和物理参数化方法计算了视热源视水汽汇的收支以及长短波辐射的加热和冷却作用。发现南下冷空气一经离开源地就开始了明显的变性过程。在冬季,变性强度随冷性气团向东南移动而逐渐增强,到达海上时变性最剧烈;在夏季,温湿变性最大区出现在我国北方,并且在陆上的变性强度比冬季要强得多。

A STUDY OF PHYSICAL PROCESSES AFFECTING THE TRANSFORMATION OF COLD AIR OVER LAND AFTER OUTBREAK OF COLD WAVES IN EAST ASIA

Authers have studied the transformation processes of cold air over land in East Asia for eight cases which occurred in different months of 1981.First, the surface eddy sensible and latent heat fluxes, and drag coefficient were estimated according to the approach of similarity theory. Then, the apparent heat source, the apparent moisture sink,and solar and long-wave radiative heating(or cooling) were further calculated through the budget method and physical parameterization algorithm. It has been found that the cold air immediately starts the transformation process over land once it moves away from its region of origin. In winter, the degree of transformation of cold air mass gradually intensified as it travelled southeastward. While arriving in the ocean, the cold air mass underwent the most significant transformation process. In summer, the most vigorous transformation of thermal and moisture fields was observed in North China and Mongolian region, with much greater intensity than that in winter.