中国干旱区土地沙砾化过程的空气流压场分析

在野外调查和资料分析的基础上，应用空气流压场原理，矢量分析法，分析了我国干旱地区不同地貌类型分区的土地沙砾化过程，及其所导致的风蚀，风积地形的分布规律，高山地区，风蚀风积地形从山顶到山木麓呈带状分布，在平坦地区，随气流强弱，扰动，就地就近起沙，形成了低缓沙丘，河湖淤泥平原，土地干裂迭加风力，形成了残丘雅丹地形，在丘陵地区的迎风坡为土地砾化，背风坡为沙化。

ANALYSIS ON AIR CURRENT AND PRESURE FIELD OF PROCESS OF LAND SANDY AND COARSE DESERTIFICATION IN ARID REGION OF CHINA

The formation of arid climate region is relation to geography position, arid current cycle,topography. The arid climate region is mainly situated in north-west part, and is about 1/3 area of China. The geography Position being far from ocean and the topography surrounded by high mountains are chief factors of arid climate formation. The circumstances of arid current cycle are main power of arid climate formation. In the winter and spring, the region iscontrolled by Mongolian-Siberian high pressure and west wind arid current, and the climate is arid, cold, windy. In summer, the climate is hot and arid because high mountains prevent moisture of ocean arid current from into region. The different topography factor makes land sandy and coarse desertification process different in region. In plain district, the desertification is only caused by various arid pressure gradient. In hilly district, the desertification is caused by the synthesized power of arid pressure gradient and additional arid pressure gradient from different topography. Land sandy desertification occurs on the against wind slope and land coarse desertification occurs on the facing wind slope. In hight mountains district, some arid current is refracted and disturbed, and the floating sand deposits; and some arid current goes up along mountains slope. As height of mountain increases, the density of arid current and floating sand decreases, and erosion on land is only blowing erosion and not grinding erosion, and without sand deposition. The study on arid current and pressure field of process of land sandy and coarse desertification in arid region of China is further going of arid region geography research in theory. It is also the essential scientific base of developing natural resources and economic development in arid clim ate region.