Characteristics Of The Surface Wind In The Southern Margin Of Taklamakan

The southern edge of Taklimakan Desert is located in the Tarim basin of the desert belt in the northwest of China.The south is along the Kunlun Mountains in the Qinghai-Tibet Plateau and the northern foot of the Altun Mountains.Due to its three-sided ring hill,east-open terrain and long-standing heat and low pressure of Tarim basin,it has formed a strong airflow convergence zone in the area of Yutian-Minfeng.The climate is extremely arid and the sandy land is evacuated,frequent wind and sand activities have an important impact on the climate environment and human activities in this area.This paper is based on the hourly observation wind direction and wind speed meteorological data of 7 meteorological stations in the southern edge of the Taklimakan Desert in the period of 2005 to 2007.The distribution and frequency of periodic variation analysis and calculation of the southern margin of the Taklimakan Desert Pishan to Ruoqiang section surface wind convergence zone.The results show:(1)There are two major wind directions in the Pishan to Ruoqiang section,roughly converging in the Yutian-Minfeng area.On the west side wind section is mainly distributed in the west-northwest-north,southwest and northwest winds.The wind direction on the eastern side of the section is mainly distributed in the north-northeast-northeast direction with the northeast wind as the main part.The surface air flow is scattered and the wind direction is changeable in the convergent zone of the middle section.(2)As for the speed,the west side of the section is stronger in the northwest to the northwest direction,and the east side of the section is larger in the northeast to the northeast direction.The wind speed of Yutian station in the convergence zone of the middle section is small,and the wind direction frequency of 0 m/s wind speed is as high as 8.11%.(3)Characteristics of sand winds(wind speed?5 m/s)are as follows: northwest winds dominated the west section and the east section is dominated by the northeast winds.when the wind blows from west to east,it changes the direction from in the Yutian-Minfeng area from the westerly to the northerly.(4)There are obvious differences in the seasonal distribution of the strong wind direction.The frequency of sand wind in spring and summer accounts for 78.98% of the total frequency of the whole year,and the frequency of sand wind in autumn and winter accounts for 21.02%,and the frequency of strong wind on the east side of the section is higher than that on the west side of the section.(5)The method of spectral analysis is often used to study the characteristics of the frequency cycle of the wind.In this way,it comes to a conclusion that the characteristics of the energy spectrum of each station have the characteristics of diurnal or semidiurnal cycles.(6)Due to the influence of topography,the wind field of the cross-section has obvious diurnal variation in different seasons,showing the wind direction transition law similar to the valley wind,the northerly wind above the mountain during the day and the southerly wind below the night.The transformation time of valley wind varies from season to season.(7)Because of the difference of the four seasons' heat and the influence of the topography,the wind speed of each station is large in the afternoon and small in the middle of the night,and the time of changing the wind speed varies with the difference of the heat.The wind speed in spring and summer is obviously larger than that in autumn and winter.(8)In the typical weather situation,the wind direction of the weak wind in the section changes clockwise in one day,the northerly wind is dominant in the daytime period,and the southerly wind is the main wind in the night period,which shows the transformation law similar to the valley wind.There is no diurnal variation of the wind direction in the section of sandstorm,and the wind direction is concentrated in a single direction.