准噶尔南部沙尘暴发生的地表条件研究

Ground-surface Conditions Resulting in Dust Storms in the South Junggar Basin

准噶尔南部可分出沙尘暴源区、易发区和少发区(或罕见区)三类,它们包括植被状况、土壤理化性质在内的地表条件存在差异。以植被盖度、植物群落多样性和土壤表层水分为变量,在费歇(Fisher)准则下建立起源区和少发区地表特征的判别函数R=-0.0576x1-0.1345x2-0.0695x3,并确定了两者划分的阈值R0=-10.07。在此基础上,对易发区地表条件的类型归属进行判别。最终查明影响沙尘暴发生的地表条件主要是植被状况,其中最为重要的是植物群落的多样性。

The south Junggar Basin can be divided into the source area of dust storms and the areas of easily occurring and seldom occurring dust storms based on their ground surface conditions including the vegetation status and soil physiochemical properties. In this paper, by taking the vegetation coverage, plant community diversity and moisture content in topsoil as the variables, the discriminant functions of ground surface features in the source area of dust storms and the area of seldom occurring dust storms are developed under Fisher rule, they are as: R=-0.0576x 1-0.1345x 2-0.0695x 3, and the threshold dividing the source area of dust storms and the area of seldom occurring dust storms is determined: R 0=-10.07. On which the types of ground surface conditions in the area of easily occurring dust storms are discriminated. The study results reveal that the vegetation status is the main factor affecting the occurrence of dust storms, especially the plant community diversity.