基于多源观测资料的2023年3月22日山东沙尘暴天气特征分析

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Abstract On 22 March 2O23，a sandstorm weather occurred in Shandong with a wide range，high intensityand long duration，making it a rare event inrecent years.It was included in the top 1O weather and climate events in Shandong in 2O23.This study analyzes the characteristics of this sandstorm weather using thedata of aerosol lidar，L-band boundary layer wind profiling radar，airquality data from China National Environmental Monitoring Center，routine ground and upper-air observations and ERA5 reanalysis data.The conclusions are as folows.（1） From January to March 2O23，the temperature in sand source areas such asMongolia and Northwest China was significantly higher than usual，and precipitation was scarce in desert regions，which formed the climatic background for the sandstorm in Shandong.The sandstorm occurs under the weather conditions of a strong Siberian high-pressure system and a Mongolian cyclone，with the pressure diference between the two systems exceeding 52 hPa during their strongest phase.（2）The Mongolian cyclone is the triggering mechanism for the sandstorm.From 2O to 21 March，a warm center developed at low levels in Northwest China and North China regions，with a temperature difference between 850hPa and 500hPa reaching 33-35C . The atmospheric stratification develops unstably，the cyclone triggers thermal instabilityand strong winds，the disturbance loosens the surface，and the upward motion lifts the surface dust and sand/stones from sand source areas into the air.When the cold front of the cyclone passes through Shandong，the horizontal transport by the northeasterly winds behind the front and dynamic deposition directly contribute to the sandstorm.The increase in the wind speed and the sharp rise in the mass concentration of PM10 correspond well with the stronger positive pressure change in 3 h.（3）The wind speed afcts the vertical diffusion of particulate matter. The aerosol lidar monitoring shows that the sand and dust transport height in Shandong is less than 2.5km ，but the high-concentration sand and dust particles are concentrated below 1km ，andas the sandstorm moves eastward and southward， the transport height gradually decreases.When the wind speed decreases，the sand and dust particles are dispersed into higher altitudes，increasing the impact height again.

Keywordssand and dust; PM10 ；particulate matter；horizontal transport；deposition

0 引言

沙尘天气一般指地面大量尘沙卷入大气层中造成视程障碍的自然现象，伴随 PM10 质量浓度升和水平能见度下降，严重的沙尘暴天气除影响城市运行、人体健康外，还可造成土壤沙化区域扩大等[1]因此，若能够全面地对沙尘天气进行研究分析，及时进行预报预测，可在一定程度上减少沙尘天气带来的危害[2]。（剩余13574字）