A Primary Analysis Of Severe Convection Weather In Heilongjiang Province

Severe convective weather is a small-scale weather system with small spatial scale and a short-time lifecycle. It is one of the most dangerous weather phenomena, which can cause fatalities and damage, so it is very important to investigate its main characterics for the purpose of prediction.This study uses the data for severe convective weather condition and the related meteorological observations based on 80 weather stations in Heilongjiang province from 1971 to 2008. According to the high latitude character in Heilongjiang province, the methods of mathematical statistics, subjective analyses and aggregative indicator and so on are adopted to analyze the data in order to draw some conclusions, including severe convective weather index and some concept models for the weather prediction.It is shown that upper cold vortex, front, upper trough and the cyclone are often accompanied by low jet as well as high jet, and meanwhile the low zone and convergence zone on the ground appear. The warm air may exist in lower part, cold air in upper part, and the inversion layer in the middle part of the atmosphere. In this situation severe convection generally happens in the junction of cold and warm air. Also the characteristics of the three types of cloud mass are investigated, i.e., isolated convective systems, band convective systems and mesoscale convective complexes (MCC).Several radar echo characteristics are found when severe convective weather appears; they are much strong echo intensity, high echo top and dense echo structure. The echo intensity gradually becomes strong, the echo area becomes large and the echo top becomes high from thunderstorms, to heavy rains, to hails, to squall lines and to tornadoes in order. Also there exist some other features in severe convection weather, such as hook echo, mesocyclone, three-body scattering, and so on.