干旱草原地区起沙通量的初步研究

Preliminary Study on Dust Emission Rate over Arid Steppe Area

通过宽范围颗粒谱仪WPS以及20 m梯度塔获得的观测资料,计算了朱日和地区沙尘天气下的起沙通量、摩擦速度以及临界摩擦速度,得到以下结论:①起沙通量大小与沙尘天气的强度呈一定的相关关系,随着沙尘天气强度的增大,起沙通量大小也增大。3月26日与4月6日两次沙尘天气下,沙尘暴和扬沙天气的平均起沙通量分别为6.0亿kg.m-2.s-1和4.14亿kg.m-2.s-1。②朱日和地区地表摩擦速度一般都在<1 m.s-1的范围内,n取1或2时,起沙率与Un*线性相关最好。③计算得到了观测粒子段的临界摩擦速度值。临界摩擦速度U*t随着粒径的增加呈先减小后增大趋势。

The dust particle concentration data measured by Wide Range Particle Spectrometer and the data observed at a 20 m meteorological tower were used to calculate the dust emission rate, friction velocity and threshold friction velocity over Zhurihe area, Inner Mongolia. The result indicated that： ①The value of dust flux was in accordance with the intense of the dust weather. The average dust flux in dust-storm weather and blowing sand weather were 6.0×10^-8 kg.m 2.s^-1 and 4.14×10 8 kg.m 2.s^-1, respectively.②The friction velocity（ Ux ） was almost less than 1 m. s^-1 . The relationship between dust emission rate and friction velocity was analyzed, when n is 1 or 2, the dust flux had the best linear correlation with U.,31in Zhurihe area. ③The threshold friction velocity of the observed dust diameter width was calculated--it firstly declined then ascended with diameter increasing.