Dust Release during Playa Activation in a Typical Semiarid Steppe

Abstract

Playas are one of the major sources of saline and alkaline dust in northern China, which release a large amount of sand and dust material every year, severely impacting the quality of the atmosphere, production and life on the Inner Mongolian Plateau in northern China. The surface characteristics of playa activation processes influence the horizontal salt migration flux, but the salt transmission volume of playas is almost unknown in dry salt lakes in a typical steppe. The functional relationship between horizontal salt dust transmission volume and the grain size content was ascertained for four different surfaces at situ sites in the Chagan Nur playa in northern China. After collecting salt dust from four surfaces (crust, broken crust, activated and sandy saline surface) formed during different stages of the desiccation process, the salt dust transmission was assessed based on the wind velocity profile, grain size, and total wind erosion particulate matter (TWEP) profiles above the playa surfaces. The particle size gradually increased from the center of the lake to the shore, while the water content decreased. The wind speed, friction velocity, and roughness of the four surfaces were as follows: sandy saline surface<crust surface<broken crust surface<activated surface. The sand transport of crust in the height range of up to 50 cm was a linear function of the sand transport rate, while the sand transport of the broken crust obeyed a power function, and the activated and sandy saline surfaces obeyed an exponential function. The formation of a stable crust surface by fine particles reduced the wind erosion of the playa, but the playa was still a potentially huge source of salt dust during and after activation and the dust generated by the activated surface (2.61 g/cm 2 •min) was 20 times that generated from the crust cover (0.13 g/cm 2 •min) during the observation period. Finally, all of the aerosol substances were <63μm.

Research Trends and Areas of Focus on Wind Erosion: A Bibliometric Analysis during 1941-2022

“…The dust released from soil erosion plays a significant role in atmospheric physics and chemistry as well as global ecosystems, and is one of the core topics in international research of dust storms and sand [134]. In 2006, approximately 50% of the articles published on wind erosion were related to the issue of dust release [135,136], indicating that research on wind erosion cannot be separated from research on dust, which will remain the major topic in this field.…”