塔克拉玛干沙漠地面风场特征及周边地区沙丘排列关系分析

CHARACTERISTICS OF SURFACE WINDS IN TAKLA-MAKAN DESERTS AND THEIR RELATIONSHIP TO THE ORIENTATION OF DUNES IN NEIGHBORING REGIONS

通过对1996～2000年17个气象站风资料的分析和计算,结合高空环流形势分析,对塔克拉玛干沙漠近地面风场特征进行了研究,并对风场特征与周边地区沙丘排列方向之间的关系进行了分析.研究表明:①塔克拉玛干沙漠近地面风场特征是在高空西风带的背景下,经过青藏高原、天山山脉的动力分支和抬升等作用下形成的.冬季,尼雅河以东盛行偏东风,以西盛行偏西风;夏季,克里雅河以西地区盛行偏西北风和西风,以东盛行东北风.②从东到西,东北风系影响逐渐减弱而西北风系影响逐渐加强;南北方向变化较为复杂.③除若羌地区外,塔克拉玛干沙漠输沙势都小于200 VU,属于低能风环境,且以单峰或锐双峰为主.在区域分布上,沙漠东部及中部强度较大,西部及南部较小.④沙丘排列方向主要由主、次输沙方向的夹角及二者的输沙比率决定,其走向与最大输沙总量垂直.

Study is performed of the near-surface wind fields in the Takla-Makan Deserts by use of 17-station winds and the high-level circulation situation, with focus on the relation between wind-field features and dunes arranged in the neighboring areas. Results suggest that in the background of upper-air westerlies, the near-surface wind features are produced from the dynamic bifurcation and lifting by Tibetan Plateau and Tianshan Mountain Ranges, as shown in the following： in winter easterly （westerly） winds prevail east （west） of the Niya River; in summer northwesterly and westerly （northeasterly） winds are prevalent west （east） of the Keriya River; the NE （NW） winds get decreased （increased） from east to west, with N-S wind strength changing in a complex manner; the sand transport potential is less than 200 VU in the Takla-Makan Deserts except Ruoqiang County, the Deserts falling into a lowenergy wind environment dominated by a single-peak or an acute hi-peak form, with the energy higher in the eastern and middle parts and low in the western and southern portions of the Deserts; the orientation of dunes depends largely on the concluded angle between the major and minor winds for carrying sands and the ratio of their transported sands, with the orientation perpendicular to the maximum sand amount transferred.