Abstract:

In this paper, a typical local dust weather process in Xilingol League in the early summer of 2018 was analyzed using the analysis data from MICAPS (Meteorological Information Combine Analysis and Process System) and NCEP (National Centers for Environmental Prediction), data from the automatic weather stations, Satellite infrared cloud map, weather radar, etc.The dust weather is mainly caused by the strong convective storm triggered by the low-level shear under the background of the upper air cold vortex circulation and occurs in the downdraft of the strong convective storm.The observation data of the automatic weather stations in every five minutes interval show that when the dust occurs, the air pressure on the ground jumps from 995.2 hPa to 1000.4 hPa, the air temperature drops, the wind direction changes from the northeast (31°) to the northwest (343°), and the wind speed increases instantaneously.According to the weather situation, in the warm and unstable atmosphere, the convective cloud cluster is developing vigorously, and the strong downdraft at the outer boundary causes a strong wind near the ground, which provides a better dynamic condition for the short-term dust weather.Before the occurrence of local dust, the dynamic and thermal conditions are conducive to the occurrence and development of severe convective weather.The main causes of local dust weather are convergence at the lower level, divergence at a high level, strong upward motion, and dryness at the middle level and underlying surface.

Key words: Convective storm, High altitude cold vortex, Short time dust, PM₁₀, PM_2.5