Wind Regime And Drift Potential In The Badain Jaran Desert Based On Observation

The Badain Jaran desert is the second largest desert in China,the surrounding area of which is very active in the process of desertification.Being one of the main sources of sand materials for sandstorms in northern China,it has brought many negative impacts on people's lives and economy development in surrounding area.Due to the limitation of traffic and environmental conditions,it is difficult to conduct observation experiments in the hinterland of Badain Jaran desert,resulting in a lack of data and materials.To conduct a further research on wind regime and wind energy environment in this area,with wind speed and direction data from March 2016 to February 2018 obtained from seven field observation stations in the hinterland and seven national weather stations surrounding the desert,I described the wind regime in the Badain Jaran desert,compared its differences between different locations,and analyzed factors affecting wind regime in different time and spatial scales.At the same time,based on the definition given by Fryberger and Dean,I calculated drift potential(DP)in this area,analyzed the dynamic conditions of sand activity.The main results and conclusions are as follows:(1)The diurnal variation of wind regime in the hinterland of Badain Jaran desert is highly regular: the lowest and highest average wind speed appears at 6:00 and 15:00 to 16:00 respectively.But on several sites a weak "double peak" phenomenon occurs,as a weaker peak appeared at around 0:00.The average wind speed at the top of sand dunes is higher than interdune,and the time when wind speed reaches its lowest and the highest value at the top of the sand dunes is 1-2 hours later than interdune.At 14:00,prevailing winds of most sites are east wind or northeast wind.At night,the wind direction at the top of the sand dunes is eastward.But wind direction at interdune is irregular.(2)For annual changes of wind regime,the average wind speed is higher from March to August of the year.The average wind speed is at its highest in June,but sand-driving wind occurs mostly in spring.In December annual average wind speed is the lowest for all stations.Wind speed at the top of sand dunes fluctuates between August and December.The prevailing wind direction at the top of sand dunes is westerly all year round,while at interdune area only in winter and spring the prevailing wind is westerly.In summer,the southeast wind accounts for a large proportion.North wind and south wind occur frequently in autumn.(3)Wind speed and direction at the top of sand dunes are in agreement with the surrounding area,and is not affected by the lakes.It is a reflection of the situation of large-scale atmospheric circulation.The site near lake basins has a specified wind condition,and local circulation generated by the underlying surface(mountain-valley wind and lake-land wind)is superimposed on large-scale circulation,changing the temporal and spatial variation pattern of wind speed and wind direction.(4)Most sites in the Badain Jaran Desert has a low wind energy environment,but sites at the top of the sand dunes have a higher drift potential(DP).DP at 14:00 is higher than other time of the day and that in spring higher than other seasons.When DP is relatively high,resultant drift direction(RDD)is mostly southeastward.RDD at the top of sand dunes is more patterned.Lake basins and water bodies have strengthened the diversity of wind energy environment through changing their surrounding thermal properties.They have a certain effect on maintaining the height of the sand mountains in the Badain Jaran Desert.(5)In this area,resultant drift potential(RDP)in spring is southeastward,and the sand dune strike(NNE)is approximately vertical to it.During this period,the occurrence of sand-drifting wind is frequent,wind speed high,and DP high,which is an important cause for sand material moving to the southeast and forming a handshake between the Badain Jaran Desert and the Tengger Desert.