Field Observation of Sand Transport under Easterly Wind Condition over Gobi Surface at the Top of Mogao Grottoes, Dunhuang

 Based on the simultaneous observational data of wind-sand flow structure over Gobi surface during a sand storm, researchers from the Dunhuang Gobi and Desert Ecological and Environmental Research Station, Cold and Arid Regions Environmental and Engineering Research Institute(CAEERI), Chinese Academy of Sciences(CAS) analyzed the temporal and spatial variations of sand transport and sand flow structure at different observational points at the top of Mogao Grottoes.

The result shows that in condition of easterly wind, when wind speed got to 10 m·s-1, there appeared an equilibrium stage of sand transport in horizontal direction at different observing points. When wind speed was stronger than 10 m·s-1, the main blown-sand activities were wind erosion and transportation, and at this time 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, sand flow structure and sand-transporting character may have significant changes.

Adopted Lattau's sand transport rate equation, they 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 surface at the top of Mogao Grottoes is about 60%.