塔克拉玛干沙漠公路沿线风沙活动的时空分布

Spatial-temporal Distribution of Blown Sand Activities Along Taklimakan Desert Highway

利用塔克拉玛干沙漠公路沿线的肖塘、满参和塔中3个定位观测站1个自然年的监测资料,对以起沙风和输沙强度为表征的风沙活动进行了分析.选取气象站标准高度10 min风速中大于临界起沙风速(≥6.0 m/s)的风,按16方位分别统计不同级别风的次数及其方位,计算输沙量.结果表明,风沙危害的主风向为偏东风,频率范围48%～76%.风沙活动集中在4～9月;从沙漠边缘向腹地风沙活动加强.向沙漠腹地深入,应加大公路风沙危害防护力度.

The Taklimakan Desert highway cuts across the simple barchan and barchan dune chain zone,complex transverse dune ridges zone and complex longitudinal megadune zone. Based on a natural year observation data of three meteorological stations （Xiaotang, Mancan and Tazhong） along the Taklimakan Desert highway, we analyzed the blown sand activities that were characterized by intensity of sand driving wind and intensity of sand transport. We select all the winds with velocity greater than the threshold velocity at the standard height of meteorological station as the study winds. We count the frequencies and directions of different level winds by 16 directions and calculate the sand transport according to Bagnold formula of Q = 5.2 × 10^-4 （ V - V1 ）^3. The study resuits show that blown sand disaster causing winds come from the north-east （NNE, NE, ENE, E） and their frequencies ranging from 48% to 76%. On time distribution, the blown sand activities were concentrated in spring and summer, especially during the period of April to August. On the spatial distribution, the intensity of blown sand activities were trending stronger from the edge to center of the Taklimakan Desert. The sand transport can reach 6309.5 kg/（ m · a） and resultant drift direction is 230° -234°at the center of the Taklimakan Desert. So we draw a conclusion that the defending measures must be enhanced in the interior desert.