Aeolian dust movement and deposition under local atmospheric circulation in a desert-oasis transition zone of the northeastern Taklimakan desert

Abstract

Taklimakan Desert, in the northwest China, is one of the main sources of dust storms in the world. Frequent dust storms have seriously affected the ecological environment of surrounding oases. Quantification of dust deposition on the different underlying surface is vital to understand the local atmospheric cycling and its effect on movement of the dust particles in desert fringe areas. To examine the contribution of airflow from different direction to the dust deposition rate, the desert–oasis transition zone between the Korla oasis and the northeast edge of the Taklimakan desert is selected as the study area. 36 h backward trajectories of air masses arriving at the study site from 1st March to 31st May 2023, were determined by using the HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory Model) model. The trajectories were categorized by k-means clustering into 3 clusters, which show distinct features in terms of the trajectory origins and the entry direction to the site. Dust collection tank were placed on five underlying surfaces from south to north: shifting sand desert, semi-shifting sand desert, desert vegetation, shelter forestland and croplands at the height of 0.2 m, 0.5 m, and 1.5 m. At the each of height, four dust collection tanks were arranged to collect the dust from 4 directions. Results show that, air masses from the south with highest frequency (46 days) and highest dust storm occurrence (91.3 %) is the main contributor of dust particles to the study area. Dust deposition rate on different underlying surfaces showed a significant decreasing trend from the desert to oasis, and the dust deposition on all underlying surfaces decreased with the height. Dust deposition corresponding to the southward wind direction is the highest, and the amount of fine dust particles are increased with the height of the dust collection tank. The results of this study could be helpful to forecast the potential occurrence and mowing pathway of dust storms, which can provide the basis for mitigation of the negative effects on the environment.