塔克拉玛干沙漠塔中地区春夏季风蚀起沙研究

利用塔克拉玛干沙漠腹地塔中地区的观测资料,对塔中地区春夏季地表土壤风蚀起沙的临界摩擦速度及其变化特征和起沙风速进行了分析研究,并计算了2008年4月19日和7月19日两次沙尘暴天气过程沙漠地表的风蚀起沙量。结果表明:塔中地区春夏季地表起沙的临界摩擦速度为0.26m·s-1;2m高度的临界起沙风速约为4.1m·s-1;两次沙尘暴过程的顺风向沙粒通量和垂直尘粒通量的平均值分别为17.44×10-4kg·m-1·s-1、13.8×10-8kg·m-2·s-1、164.69×10-4kg·m-1·s-1和799.77×10-8kg·m-2·s-1;沙尘通量的变化与风速及摩擦速度的变化具有一致性。

Dust Emission by Wind Erosion in Spring and Summer at Tazhong of Taklimakan Desert

Based on the field observation and meteorological data at Tazhong of Taklimakan Desert, the critical friction velocity of dust emission by wind erosion and the threshold sand-moving wind velocity in Spring and Summer are analyzed in the paper. The dust emissions by wind erosion at Tazhong during the two sandstorm events on April 19 and July 19, 2008 are calculated. The results indicate that the critical friction velocity is about 0.26 m·s-1 and the near-surface threshold sand-moving wind velocity is about 4.1 m·s-1. The average values of down-wind sand flux during the two sandstorm events on April 19 and July 19, 2008 are 17.44×10-4 kg·m-1·s-1, 13.8×10-8 kg·m-2·s-1 respectively, and the vertical dust flux during these two sandstorm events are 164.69×10-4 kg·m-1·s-1 and 799.77×10-8 kg·m-2·s-1 respectively. The variation of dust flux is consistent with the variations of the wind velocity and the friction velocity.