The Wind Character Of Boundary Layer In The Hinterland Of The Taklimakan Desert

The wind character of Boundary layer in the Hinterland of the Taklimakan Desert was given as a result of eight months measurement using CFL-03 wind profiler radar. The applicability of the radar for desert use and the accuracy of the data was verified by the comparison of three different instruments. The wind database of boundary layer was created and the wind structure was investigated in detail in TaZhong by using the measurement data from April to November 2010. The wind character during thunderstorm and sandstorm was also analyzed. The main results are given as follows:1 From November to May, wind direction of upper layer is west and wind speed is relatively high, wind direction of lower layer is east and wind speed is relatively low. The wind structure in April, May, October, November's is similar, proportional to wind speed and height and east wind at the bottom and west wind at the top. Wind direction changes as altitude differs from 800 meters to 1600 meters. Form June to September, wind speed of upper layer decreases and the lower layer increases, Wind speed changes little from the ground to high altitude. A clear wind shear region exists in summer, in 100m to 200m altitude range due to the impact of weather systems. Maximum wind speed increases up to 225% compared with neighboring height.2 East wind exits in the 850hPa level all year round in TaZhong except for June in which the wind direction is west. The wind speed in June is larger than the other months in which the wind speed range is 2~3.5m/s. The average wind speed in the 700hPa level in summer is lower compared with spring and autumn. The average wind direction in the 700hPa level in June, August and September is east and in April, May, July, October and November is west. The wind speed in the 500hPa level is relatively high in April and May, in June it startes to decrease and in September reaches minimum, in October it begins to increase and reaches maximum in November. The wind direction is west except for June and September in which is east.3 April 19 2010 in TaZhong, wind direction changed from east to west below the 1000m altitude before the outbreak of the sandstorm. When the sandstorm occurs the wind direction was east below the 1500m altitude. Wind speed near ground increased rapidly to 18.3m / s during the forming of sandstorm. When the sandstorm occurs the wind speed decreaed to 10m/s. In the altitude range of 300m to 1000m the wind speed was lower during the sandstorm. In the altitude range of 1000m to 2000m the changes of wind speed was the same as near ground. Wind speed in above 3000m was as high as 20m/s during the sandstorms. There was a significant sedimentation of sand over the area during the sandstorms, the average sinking speed was 1.2m/s.4 July 12, 2010 in TaZhong, Surface wind messed during the thunderstorm, wind direction changed from east to west below the 1200m altitude and changed from west to east above the 1200m altitude. Wind speed below the 3000m altitude increased significantly during the thunderstorm. Wind speed in the altitude range of 1500m to 2500m was higher during the precipitation period. Wind speed above 3200m altitude was lower during the precipitation period. There was a low level jet over the TaZhong in the altitude range of 900m to 1400m during thunderstorms and the average wind speed was 17.1m/s. A strong downdraft exited during the thunderstorm and the vertical velocity was approximately 3.0m/s. During the precipitation the downdraft strengthened, the water droplet's average sinking speed was 5.1m/s and the maximum speed was 8.0m/s, much higher than the average vertical velocity in July which is 0.1m/s.