Suspended dust particle characteristics during an sandstorm on 29 February 2008 in Minqin area, China

Abstract

Aeolian dust is one of the main aerosols in the troposphere, and plays an important role in the Earth’s climate system. In this study, detailed meteorological conditions and dust particle diameters were measured at three sites with different landscape characteristics in the Minqin oasis area of northwest China, on 29 February 2008. We show that as dust storms progressed through the desert into the oasis, variation in the character of the underlying land surface not only influenced the wind profile by modifying the frictional velocity of air (U∗), aerodynamic roughness length (Z0), horizontal sediment flux, and dust concentration of the near surface sublayer (1–49 m), but it also changed the vertical structure of the aeolian sediment transport pattern. The particle size frequency distributions at three distinct sites were all unimodal, comprising a large number of aeolian dust particles with sizes less than 63 μm (more than 65%). During transport, dust particle populations shifted to smaller sizes. Clearly, the influence of landform, windbreaks, and vegetation cover on horizontal sand-dust flux decreased with height as well as increasing particle size, with smaller aeolian particles being more easily captured by windbreaks, and vegetation.