Identification and quantitative analysis of dust trajectories in the Hexi Corridor

Abstract

Dust storms in Northwest China are a major component of global dust storms and it is important to be able to identify and quantitatively analyze their dust trajectories. In this study, the dust events, sources, and transport paths in the Hexi Corridor were identified using ground-measured PM10 data, Navy Aerosol Analysis and Prediction System (NAAPS) data, the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model, and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) data. Based on these data, the dust trajectories were then screened. Dust events from five cities in the Hexi region were determined for 2015–2018. Next, five main areas affecting the Hexi region were defined; which included the Gobi region between Xinjiang and Mongolia (XG), Taklimakan Desert (TD), Kumtag Desert (KD), Qaidam Basin (QB), and Badain Jaran and Tengger Deserts (BJTD). We quantified the contributions of the dust trajectories for these five main areas and determined that the major areas that affect the Hexi region are the BJTD and KD, which are located close to the study area. The contribution of the dust trajectories in XG is smaller, owing to its higher vegetation coverage, greater precipitation, and larger particulate matter size. Of the five main areas that affect the Hexi region, the dust intensity in TD is the highest. However, its dust trajectory contribution to the study area is lower. This is because the dust is not elevated to the free atmosphere readily by the easterly wind, owing to the closed mountain basin location. The contribution of the dust trajectories in the QB to the study area is the lowest, mostly due to the low dust intensity in this region and the obstruction of dust trajectories by the Qilian Mountains.