关键词: 沙尘暴, 稳定度, 狭管效应, 气象要素突变

Abstract: According to the upper-air sounding radar data before sandstorm breaking out, the automatic meteorological observing data during sandstorm process in Jiuquan base station and the conventional observing data in other stations, we analyzed a case of weather events occurred in the west Mongolia and Jiuquan area of Gansu Province on July 12th, 2004. The stability of atmosphere, the mechanism of local terrain influencing sandstorm, and the characters of underlying Earth surface, as well as the variations of ground meteorological elements and ground temperature in event process have been studied. The result showed that (1) the instable atmospheric stratification played triggering role, (2) the \!canalization\" resulted from the special local terrain made intensifying action, (3) the rapidly increasing wind provided favorable dynamical condition. The atmospheric pressure and relative humidity obviously fluctuated in the prophase, the midterm and the later stages of sandstorm, further more, the ground surface metrological elements such as atmospheric temperature and pressure, relative humidity and underlying surface characters had abruptly changed after the event.

Key words: sand-dust storm, degree of stability, canalization, abrupt change of meteorological elements