Progress of synoptic studies for heavy rain in China

Abstract

During the past 70 years since 1949, Chinese meteorologists have made a great deal of researches on heavy rain in China and gained huge achievements. This article is a brief review about the categories, the large scale background synoptic conditions, the influencing weather systems in various scales, the physical mechanisms, and the methodology of diagnosis and forecasting of the heavy rain in China. The researches reveal that:(1) The heavy rain processes in China have distinct regional, seasonal and time-phased features. There are three seasonal large scale rain bands in east China, moving from south to north and with distinct jumping in locations. The large scale circulation patterns include steady meridional type, steady zonal type and middle-low latitude interactional type etc., and different areas have different special situations of circulation. (2) The summer precipitation in China is closely related to the westerly long waves, blocking-high pressures, subtropical high and tropical circulations as well as the East Asian summer monsoon systems etc. The upper air troughs, surface cyclones, fronts, upper air cold vortexes, low level shear lines and cyclonic vortexes as well as high and low level jet streams etc. are the major synoptic and subsynoptic systems playing important roles in most heavy precipitation processes. Typhoon is the strongest heavy rain system, and most of heavy rain processes occurred in near-coast provinces of China are closely related to typhoon. (3) Mesoscale systems, especially mesoscale convective systems are the direct producers and carriers of heavy rain phenomena. The article discussed the heavy rain diagnosis methods based on the atmospheric dynamics and thermodynamics theories. The diagnosis analyses make the heavy rain studies objectively and quantitatively. It will be helpful for deepening understanding the formation mechanisms of heavy rain and improving the heavy rain forecasting in different ranges. At the end of the article a thinking and outlook about the heavy rain studies in future are presented.

Keywords

• heavy rain
• synoptic meteorology
• research progress
• weather system
• diagnosis
• forecasting