Disaster characteristics of severe convective weather

Strong convective weather is based on large-scale weather system, which affects or determines the generation, development and movement of small-scale weather system, and small-scale weather system has feedback effect on large-scale weather system. As far as Guangdong Province is concerned, the characteristics of strong convective weather are mainly manifested in the following aspects:

(1) occurs early and ends late. The severe convective weather in Guangdong generally begins in February and gradually decreases after September. Some years can appear in 65438+ 10 in advance and end in10 ~ 65438+February.

(2) High strength and strong destructiveness. The severe convective weather in Guangdong, like severe convective weather in other areas, has the characteristics of high vertical speed, strong suddenness and great destructive power. For example, when severe convective weather occurs, the instantaneous wind speed in some processes reaches 12 or even exceeds 100 m/s.

⑶ Small horizontal scale and short life history. Strong convective weather is one of the most common natural disasters in Guangdong, with strong winds, squall lines, hail and tornadoes appearing frequently. For example, in some years, it hails four times a day, and the longest hail can last for half an hour. In some months, there may be hail for several days in the whole province. The horizontal scale of strong convective weather is small, generally less than 200 kilometers, and some are only a few kilometers. Life history is very short, usually only a few hours to dozens of hours. In addition, it also has the basic characteristics of large gradient of meteorological elements, non-geostrophic balance and non-static balance. Convective weather is easy to form and develop in some specific areas, such as on both sides of mountains, at the border between land and sea, around lakes and swamps. Therefore, the physical process of the formation of various severe convective weather is not exactly the same, which is closely related to the influence of dynamic and thermal effects of the underlying surface.