浑善达克沙地风蚀坑形态特征及其影响因素

Impact Factors and Morphological Characteristics of Blowouts in Hunshandake Sandland

风蚀坑是沙质草原固定沙地活化的主要表现形式，其持续活化的结果将导致沙漠化扩展和生态环境恶化。采用实地测量方法，测定了129个风蚀坑走向、长度、宽度等形态指标。研究表明：①研究区风蚀坑形态特征受NW、SW和W3个风向的综合影响；②风蚀坑走向呈WNW-ESE（112．5°）走向，有74．5％的风蚀坑走向（100°～120°）与SW风垂直，和W风呈20°左右的夹角，并影响风蚀坑的几何形状特征；③按风蚀坑长宽比值所反映的几何形状，可划分为卵圆形、长条形、狭长形和带形风蚀坑；依风蚀坑的地表形态特征，可划分为碟形、梯形、沟谷形、杯形和坡形5种风蚀坑。

Blowouts were the main forms of fixed sand activation in sandy grassland. The results of blowouts sustained activation were lead to expansion of desertified land area and deterioration of the ecological environment. In this article, the morphological characteristics of blowouts towards, length and width were determined with used field method to measurement the 129 activation fixed dune blowouts. The results showed that the morphological characteristics of blowouts in study area were the combined effects of the NW winds, W winds and SW wind. Blowouts toward were WNW-ESE（112.5°）, and the 74.5% blowouts toward （100°-120°）were vertical SW wind, or were about 20° angle of the W wind. This relation influenced the blowouts geometry features. Based on the reflected in the geometry of the ratio of the blowouts length and width, the blowouts were divided the ovoid blowout,slong strip blowouts,slim blowouts and with type blowouts. Based on the surface topography difference, the blowouts were divided the dish type blowouts, trapezoid type blowouts, valley type blowouts, cup type blowoutsand slope type blowouts. In the same time, this article discussed the effection for blowouts formation and evolution in process of blowouts development from the aspects of primtive landform, surface feature and human activity factors.