Exploration of playa surface crusts in Qehan Lake, China through field investigation and wind tunnel experiments  

作　　者：LIU Dongwei HAN Lijing KOU Zihan GAO Xinyu WANG Jingjing 

机构地区：[1]School of Ecology and Environment,Inner Mongolia University,Hohhot 010021,China [2]College of Geography and Remote Sensing Sciences,Xinjiang University,Urumqi 830017,China

出　　处：《Journal of Arid Land》2023年第5期491-507,共17页干旱区科学（英文版）

基　　金：funded by the National Natural Science Foundation of China (42067013, 41571090)

摘　　要：Globally,many lakes are drying up,leaving exposed lakebeds where wind erosion releases dust and sand rich in salt and harmful heavy metals into the atmosphere.Therefore,understanding the characteristics and spatial distribution of playa surface crusts is important to recognize the manifestation of salt dust storms.The objective of this study was to explore the playa surface crust types as well as their spatial distribution and evolution of Qehan Lake in Inner Mongolia Autonomous Region,China to understand the salt dust release potential of different types of playa surface crusts.Various crust characteristics were investigated by field sampling in Qehan Lake,and playa surface crusts were further divided into five types:vegetated areas,salt crusts,clay flats,curly crusts,and margins.It should be noted that curly crusts were distributed in clay flats and covered only a small area in Qehan Lake.The spatial distribution characteristics of playa surface crust types were obtained by supervised classification of remote sensing images,and the salt dust release potential of crusts was explored by the wind tunnel experiments.The field investigation of Qehan Lake revealed that playa surface crust types had a circum-lake band distribution from the inside to the outside of this lake,which were successively vegetated areas,clay flats,salt crusts,and margins.The spatial distribution patterns of playa surface crust types were mainly controlled by the hydrodynamics of the playa,soil texture,and groundwater.There was a significant negative correlation between crust thickness and electrical conductivity.The results of the wind tunnel experiments showed that the initial threshold of friction wind velocity for the salt dust release was higher in clay flats(0.7–0.8 m/s)than in salt crusts(0.5–0.6 m/s).Moreover,the particle leap impact processes occurring under natural conditions may reduce this threshold value.Salinity was the main factor controlling the difference in the initial threshold of friction wind velocity for the salt dus

关 键 词：playa surface crust curly crusts salt crusts salt dust release wind tunnel experiments Qehan Lake 

分 类 号：P467[天文地球—大气科学及气象学]