Statistical Characteristics of Gust Fronts and Thunderstorm Initiation Associated with Gust Fronts in the Beijing Area

To analyze the statistical characteristics of gust fronts, there are 388 cases of gust fronts which occurred in warm season (May to September) in the time period 2006-2015 and were observed by reflectivity and radial velocity data of CINRAD-SA Doppler Radar being included in the statistics. The results show that the reflectivity of thunderstorms which produced gust fronts are between 40-71dBz, in which 96.1% of the thunderstorms’ radar reflectivity are above 50dBz. Among these thunderstorms, 48% maternal thunderstorms are single thunderstorms, 25% are multicell storms , 21% are squall lines , and the rest are linear thunderstorms.

The numbers of gust fronts are the most in July and August, which occupy about 63.8%, while June ranks second. May and September are the least. The gust fronts often appear in the afternoon to the night, whose intensities are between 10-20dBz and lives last for about 1 to 2 hours. There are 249 cases triggered convection in 388 processes, which occupied 64%.

In this paper, sounding data and automatic station data are used to analyze 8 processes, in which gust fronts triggered convective storms. The results show that, (1) if there are two or more gust fronts get crossed, or gust fronts cross with other boundary layer convergence lines, it would trigger convective storms easily. (2) If the gust fronts pass the instability area, the convective storms would be triggered easily. (3) The thunderstorm would develop if the gust fronts with them.