Dynamic characteristics of wind and PM10 over desert-oasis transition zone during dust events

Abstract

Dust storm events generate aeolian dust as one of the main aerosols in the atmosphere, with significant impacts on air quality and human health. Further study is needed on the dust emission processes in source regions and the impacts of underlying surfaces with forested windbreaks on the transport of wind flow and PM10 to develop more accurate dust concentration forecasts. Synchronized monitoring of wind velocity and the PM10 concentration was performed along the dust transport pathway crossing the desert and oasis in Minqin County, Gansu Province, China. Results indicated that the PM10 concentration and flux responded quickly to wind velocity in the desert with both having obvious power function relationships. The addition of supra-regional transport of PM10 particles led to an abnormal increase in PM10 concentration and flux. Between desert and oasis, a positive linear function relationship of PM10 concentrations and quadratic function relationship of PM10 flux exist. The dynamic transfer process of PM10 in the oasis roughly depends on the condition of PM10 in the desert area. Forested windbreaks significantly reduced the mean wind velocity and PM10 flux by 65.02% and 67.63%, respectively. However, forests had a weak influence on the mean PM10 concentration. The effects of forested windbreaks on the PM10 concentration are related to the windward wind velocity. With increasing velocity, difference of PM10 concentration from desert to oasis turned from negative to positive, while the positive effects of the forested windbreak system can be enhanced by an increase in the windward wind velocity.