The varying fetch effect of aeolian sand transport above a gobi surface and its implication for gobi development process  

作　　者：Chunlai Zhang Guoru Wei Xueyong Zou Zhenting Wang Qing Li Xuesong Wang 

机构地区：[1]State Key Laboratory of Earth Surface Processes and Resource Ecology,MOE Engineering Research Center of Desertification and Blown-sand Control,Faculty of Geographical Science,Beijing Normal University,Beijing,100875,China [2]Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou,730000,PR China [3]Hebei Engineering Research Center for Geographic Information Application,Institute of Geographical Sciences,Hebei Academy of Sciences,Shijiazhuang,050011,China

出　　处：《International Soil and Water Conservation Research》2022年第4期623-634,共12页国际水土保持研究（英文）

基　　金：supported by the National Natural Science Foundation of China(No.41630747).

摘　　要：The Gobi deserts are important landscapes and major sandstorm source areas in arid northwestern China.Unsaturated sand flow and decreasing sand supply capacity is well known as the basic characteristics of gobi surface,but relatively little attention has been paid to the fetch effect of sand transport which is closely related to sand supply and indicative of wind erosion process in gobi.Using a field experiment,we investigated the spatial and temporal variations on a manually disturbed gobi surface downwind a sand-blocking belt and a sand-fixing belt by measuring the sand transport rate and the height profile of flux density at different fetch lengths during a sequence of wind erosion events.Results showed that the sand supply capacity determined the critical fetch length(Lc)for the sand transport rate so that the fetch effect varied with wind erosion proceeding due to depletion of erodible material.The height profile of flux density above the surface followed two distributions:an exponential decrease with increasing height,which commonly occurred above the newly treated gobi surface during the early wind erosion events;or a Lorentzian distribution with a peak flux at a certain height,which often happened in the later wind erosion events.The varying fetch effect,decreasing sand transport rates,and the nonerodible area expanded downwind are an epitome of the gobi development and expansion process from the perspective of wind erosion.

关 键 词：GOBI Wind erosion Sand transport Fetch effect Gobi development 

分 类 号：TV14[水利工程—水力学及河流动力学]