摘要
通过一次沙尘暴天气过程对莫高窟顶不同观测点戈壁风沙流结构和输沙率的时空变化特征进行了系统同步观测。观测表明,偏东风条件下,当风速为10 m.s-1时,水平观测方向上存在一个各点输沙率平衡的阶段,即崖顶戈壁至鸣沙山边缘戈壁各观测点的输沙率相当;当风速大于10 m.s-1时,戈壁地表以风蚀搬运作用为主,出现了戈壁向鸣沙山的长距离风沙搬运;当风速小于10 m.s-1时,戈壁沙物质的长距离搬运作用不明显。不同风况及沙源条件下,风沙流结构和输沙特征会发生显著变化。借鉴Lattau输沙率方程,运用风速和输沙率推算各观测点输沙率的时空变化,计算结果表明,在风速为10 m.s-1左右时,窟顶戈壁带的输送效率约为60%。
Based on the simultaneous observational data of wind-sand flow structure over Gobi land during a sand storm, the temporal and spatial variations of sand transport rate and wind-sand flow structure at different observation points atop Mogao Grottoes were measured and analyzed. The result shows that in condition of easterly wind, when wind speed was about 10 m. s^-1 , there appeared a balanceable stage of sand transport rates in the horizontal direction at different observing points, where the sand transport rates at different points from the cliff to the sand mountain were nearly the same. When wind speed was stronger than 10 m. s^-1, the main wind-sand activities were wind erosion and transportation, and long distance transportation of sand material from Gobi land to the Mingsha Mountain was obvious; when wind speed was below 10 m. s^-1, the long distance transportation of sand material was not strong. Under different wind speed and sand supply conditions, wind-sand flow structure and sand-transporting character may have significant changes. With the help of Lattau＇s equation of sand transport rate, we used the data of wind speed and sand transport rate to calculate the temporal and spatial variations of sand transport rates at different observing points. According to the calculation, the transfer efficiency of the Gobi land atop Mogao Grottoes is about 60 %.
出处
《中国沙漠》
CSCD
北大核心
2010年第3期516-521,共6页
Journal of Desert Research
基金
国家自然科学基金项目(40671022)
国家重点基础研究计划(2009CB421300)资助
关键词
莫高窟
戈壁
风沙运动
输沙率
Mogao Grottoes
Gobi
wind-sand activity
sand transport rate
