Statistics of Gust Fronts Character and Condition Analysis of Convective Storm Which are Triggered by Gust Fronts in Beijing Area

Reflectivity and radial velocity data of CINRAD-SA Doppler Radar and subjective identification method are used in this article to make statistics of the gust fronts in warm season (May to September) in 2006-2015, and there are 410 processors. The gust fronts occur high frequency in July and August, which occupied about 73% of the total number, June ranks second which about 16%, and May and September are the least months. The results show that the reflectivity of thunderstorms which produced gust fronts are between 40-71dBz, and about 7% thunderstorms’ reflectivity of radar are between 40-50dBz, 56% are between 50-60dBz, and 37% are above 60dBz. There were 252 processors triggered convection in 410 processors, which occupied 62% in total.

Sounding data, automatic station data, the wind profiles, microwave radiometer and the Variational Doppler Radar Analysis System (VDRAS) are used to analyze five processors in which gust fronts triggered convective storms and other five processors not triggered convective storms. The results showed that, (1) if there are two or more than two gust fronts join, there will trigger convective storms. (2) If the gust fronts pass the instability area, the convective storms would be triggered easily. (3) If the gust fronts moving directions are consistent with the environment wind, the convective storm would be triggered easily.