Abstract: At present, the monitoring of the vertical structure of sand and dust mainly comes from ground monitoring stations. Based on the data from a lidar network consisting of 6 stations in Gansu Province, China, this paper explored the distribution characteristics of high-altitude sand and dust during a sand and dust process on May 30–31, 2021, and revealed the sources, transmission, and development trends of sand and dust for the process. Firstly, a qualitative analysis was conducted on the sand and dust particles, revealing the temporal and spatial evolution characteristics of particulate matter during the transportation, and the sources of sand and dust were explored using hybrid single-particle Lagrangian integrated trajectory (HYSPLIT) model. Secondly, the concentration of high-altitude particulate matter was estimated quantitatively based on extinction coefficient. The following conclusions were drawn: (1) Qualitative analysis found that during the period of strong dust in Jinchang and Wuwei, the development height of dust was close to 2.5 km, the extinction coefficient exceeded 1 km-1, the depolarization ratio increased to 0.26, and at the same time, the irregularity of dust particles was high and the particles had obvious external transmission characteristics. While the sand and dust transported eastward, the impact height of the sand and dust continuously decreased, and the intensity of the sand and dust weakened. However, the irregularity of the sand and dust particles did not show a significant weakening trend. (2) HYSPLIT backward trajectory showed that the dust mainly came from Badain Jaran Desert and Tengger Desert, and was transported from northwest to southeast. (3) Quantitative analysis found that the 532 nm extinction coefficient at the height of 200 m had a high linear correlation with the observed PM10 mass concentration on the ground, with an R2 of 0.814, and the fitting values of PM10 mass concentration near the ground at each lidar station were close to the corresponding observed values.

Key words: lidar network, sand dust, extinction coefficient, particulate mass concentration, fitting