若尔盖高原近30年沙地变化趋势分析

Analyses on Change Trend of Sandy Land in Zoige Plateau in Last 30 Years

以若尔盖高原为研究区域,利用遥感数据资料和GIS技术,对该地区1975年、1990年、2000年、2005年沙地面积变化进行了监测,结果显示1975年以来的这30a间,沙地以0.76%的年平均增长率增长,尤其是1990年到2000年这10a间,沙地面积的增长最为迅猛,同时研究发现沙地的分布具有地带性规律。分析沙地扩张的原因得出:过度超载放牧为主要原因,气温升高、降水减少以及大风因素为沙地的扩展提供了必要的气候条件。

RS data files and GIS technology were employed to monitor the change of sandy land area on Zoige plateau from 1975 to 2005. The results showed that the sandy land area increased by a rate of 0.76% per year in the past 30 years. Especially during the period of 1990＇s, the increasing rate was the fastest. Besides, it is demonstrated that the sandy land has a regional distribution. Study results also showed that over grazing is the main reason leading to the expansion of sandy land, and the factors of air temperature arising, rainfall decreasing, and heavy wind frequently blowing are the necessary conditions.