乌兰布和沙漠新月形沙丘迎风坡风速变化的初步研究

A Preliminary Study on Variation in Wind Velocity and Sediment Transport Rate on Windward Slope of Barchan Dune

对乌兰布和沙漠新月形沙丘表面风速的野外观测结果表明，沙丘迎风坡气流加速量主要和沙丘坡面形态、迎风坡前来流风速有关，迎风坡风速放大率介于1．02～1．59之间。近地面风速和输沙强度由坡脚至丘顶总体呈递增趋势，丘顶风速和输沙率最大，到背风坡因涡流作用。风速由丘顶至坡脚减小，输沙率锐减，相对于丘顶的风速率变化在0．17～0．49之间。由于输沙率与起沙风速的立方成正比，因而风速在迎风坡上向丘顶增加时．丘顶区域的输沙率（相对于坡脚）将成倍增加。

Field measurement of surface wind velocity and sediment transport rates was made on barchan dune in Wulanbuhe desert to understand. The results show that the wind velocities increasing upon windward slopes of the dunes vary with both slope morphology and wind velocity at the foot of the dunes. The velocity amplification factors range from 1.02 to 1.59. Wind velocity and sediment transport increase from foot of slope to the top as a whole, and decrease on leeward slope. On the whole slope sediment transport and wind velocity is the greatest at the crest. With the increase of wind velocity, sediment transport increases in reduplication.