Abstract: Based on multiple data such as synoptic data, HYSPLIT, lidar and wind data, a severe sandstorm process in Gansu Province, China, from March 26 to 28, 2019 is comprehensively analyzed, and its occurrence, development, temporal and spacial variation, vertical structure features as well as the source and transport path of the sandstorm. The results show that, (1) the horizontal trough at upper level is the key factor causing the sandstorm. The sandstorm originated from the Taklimakan Desert and affected Gansu Province from west to east, resulting in serious air pollution in several downstream cities. (2) The dust transport path reached the north of Gansu Province, and there was obvious sedimentation during the eastward movement of the dust, resulting in the continuous reduction of dust concentration in the process of transport. It is shown that the analysis of dust transport time can provide reference for the air quality prediction in downstream cities. (3) For the semi-arid desert areas, strong dust may also occur even when the wind speed is small. The results of this study indicate that the ground-based lidar products can not only be used to analyze the vertical development of the sandstorm, but also act as a good indicator for the transport path and source of the sandstorm.

Key words: sandstorm, lidar, hybrid single-particle Lagrangian integrated trajectory model, weather conditions