Analysis on characteristics of the sandstorm weather in Shandong on 22 March 2023 based on multi-source observation data

GAO Leina; LIU Chang; ZHANG Zeming; LÜ Weiqi; LU Xuening

doi:10.19513/j.cnki.hyqxxb.20241125001

Abstract：On 22 March 2023,a sandstorm weather occurred in Shandong with a wide range,high intensity and long duration,making it a rare event in recent years.It was included in the top 10 weather and climate events in Shandong in 2023.This study analyzes the characteristics of this sandstorm weather using the data of aerosol lidar,L-band boundary layer wind profiling radar,air quality data from China National Environmental Monitoring Center,routine ground and upper-air observations and ERA5 reanalysis data.The conclusions are as follows.(1)From January to March 2023,the temperature in sand source areas such as Mongolia 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 difference between the two systems exceeding 52 hPa during their strongest phase.(2)The Mongolian cyclone is the triggering mechanism for the sandstorm.From 20 to 21 March,a warm center developed at low levels in Northwest China and North China regions,with a temperature difference between 850 hPa and 500 hPa reaching 33-35 ℃.The atmospheric stratification develops unstably,the cyclone triggers thermal instability and 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 affects the vertical diffusion of particulate matter.The aerosol lidar monitoring shows that the sand and dust transport height in Shandong is less than 2.5 km,but the high-concentration sand and dust particles are concentrated below 1 km,and as 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.