时距和距地面高度一直是风况资料统计中的普遍问题,不同时距和不同高度的风况资料反映真实情况的准确度不同。利用中国科学院策勒荒漠草地生态系统国家野外观测研究站自动气象站及野外地面梯度风实际观测资料,对策勒绿洲-沙漠过渡带10 m高不同时距风速、10 min时距不同高度风速、平均风向及起沙风频率四个方面的问题进行分析。结果表明:不同时距的平均风速之间、最大风速之间、平均风速与最大风速之间均有比较稳定的关系,不随时间发生较大变化;不同高度的风速关系存在随距离接近拟合程度越好的总体规律,但在60 cm处有一定的偏离,主要与地表植被的平均高度有关;利用矢量合成法计算10 min风向,发现2 m高风向比10 m高风向沿逆时针方向偏转约45°;以气象站整时风资料与地面2 m高观测1 min风资料分别统计起沙风频率,发现在系统性天气中二者变化趋势一致,但在偶发性起沙风天气中会有较大差异。
Time duration and height above ground surface are universal problems in analyzing wind data. In this paper the wind data from automatic weather station of Qira Station for Desert Stepper Ecosystem Research and Observation at south Xinjiang,China and ground-based observation wind data were collected simultaneously.Wind velocity relation between different time duration at the height of 10 m,wind velocity relation of 10 min duration with different heights,frequency of sand-moving wind velocity are calculated by two different time duration,and wind direction relation between 2 m and 10 m height are analyzed also. The results showed that each two height wind velocity has steady relation. The wind velocity relation of different heights presents the same trend when the height approaches to 10 m,but in the height of 60 cm it violated the total rule,that may be related to the disturbance of vegetation status. Using vector resultant method to calculate wind direction in Qira area,it is found that 2 m-height wind direction dropped about 45° in counterclockwise rotation than that of at 10 m-height.Frequency of sand-moving velocity calculated either by the wind data from Qira Station or by ground-based observation system has similar various changes when in systematic windy days. However in the accident sand-moving windy day it has reversed sign. Therefore,the ground-based wind observation system should be set up in the shelter belts construction to improve sand-proof effectively.