近20年祁连山地区土地荒漠化时空演变分析——以张掖市为例

Analysis on Spatial-Temporal Evolution of Land Desertification in Qilian Mountains in Recent 20 Years—A Case Study of Zhangye City

为了有效开展祁连山地区土地荒漠化的防范和治理,以甘肃省张掖市为研究区,基于2000—2020年遥感数据对研究区内土地荒漠化进行长时间序列监测,以归一化植被指数指标表征土地荒漠化,揭示土地荒漠化时空格局演变特征,并运用地理加权回归模型识别土地荒漠化变化驱动机制。结果表明:近20年间研究区土地荒漠化面积整体呈现下降趋势,荒漠化土地总体呈现“北高南低、西高东低”的分布特征;极重度荒漠化是主要的转出者,而轻度荒漠化和中度荒漠化是主要的转入者;气温、降水等内部驱动因素是土地荒漠化最重要、最根本的影响因素,人口数量、耕地面积、牲畜数量及荒(沙)地造林面积是土地荒漠化最直接的影响因素。研究结论:祁连山地区土地荒漠化的形势整体向好的方向发展,退耕还林、退牧还草等一系列政策与治理项目对区域生态恢复与建设和遏制土地荒漠化具有重要作用。

In order to effectively prevent and control desertification in the Qilian Mountains,this paper selected Zhangye City of Gansu Province as the study area,based on remote sensing data from 2000 to 2020,it monitored land desertification in the study area for a long time series,and used normalized difference vegetation index(NDVI)to characterize land desertification and indicated the spatial-temporal evolution characteristics of land desertification,besides,it used geo-weighted regression model to identify the driving mechanism.The results showed that the desertification area in the study area showed a decreasing trend in the last 20 years,and the desertification land showed the distribution characteristics of"high in the north and low in the south,high in the west and low in the east";extremely severe desertification was the main transfer-in,while mild desertification and moderate desertification were the main transfer-out;the internal driving factors such as temperature and precipitation were the most important and fundamental influencing factors of land desertification,while the number of population,cultivated area,number of livestock and afforestation area were the most direct influencing factors of land desertification..The study concludes that,the desertification situation in Qilian Mountains is developing in a good direction,and a series of policy and control projects such as forest rehabilitation from slope agriculture and pastureland rehabilitation play an important role in regional ecological restoration and construction and desertification prevention.