我国北方典型沙漠化地区近30a风速变化特征

Wind-velocity Variation in Recent 30 Years in Three Typical Desertified Counties of North China

利用毛乌素沙漠的乌审旗、浑善达克沙地的多伦县和科尔沁沙地的奈曼旗1970—2000年逐日平均风速资料探讨了沙漠化地区的风速变化特征。3个旗县在4月和11月为高风速期,8月为低风速期;乌审旗年均风速30 a来基本处于减弱趋势,多伦县和奈曼旗的年均风速没有表现出稳定的变化趋向;用Weibull函数拟合不同时段内的风速分布效果都很好;风速的方差较大,且与平均风速成正相关;以不同时距平均风速为参数计算的输沙量相差很大,应该引起足够的重视。

Wind is the force to drive sand grains＇ movement, therefore close relative to sandy desertification, which is a serious environmental problem in most parts of North China. Wind speed must be known before the desertification is controlled efficiently. The variation of wind velocity was discussed by using daily mean wind speed data from 1970 to 2000. The data came from three regular weather stations, namely, Wushen, Duolun and Naiman county stations, located respectively in Mu Us Desert, Otindag Desert, and Horqin Desert. Results are that： （1） two peaks appeared in wind speed variation in a year, and the first in April, the second in November; （2） the wind speed decreased in Wushen County, and fluctuated in Duolun and Naiman counties in recent 30 years; （3） wind speed distribution follows very well the Weibull function; and （4） the differences between sand transport fluxes which were respectively predicted by differently interval mean wind speed, are considerable.