科尔沁沙地作为中国北方生态脆弱区,植被覆盖变化受气候变化与人类活动的双重影响。基于2000—2020年科尔沁沙地的归一化植被指数(NDVI)、降水量及土地利用遥感解译结果,采用网格化分析、相关性分析、土地利用转移矩阵等方法,定量评估降水与土地利用变化对植被覆盖的驱动机制。结果表明:1)科尔沁沙地的植被覆盖指数(NDVI)呈上升趋势(增速0.007 5/a),呈东南和中部的西辽河流域高、南北两边较低、西南最低的空间格局;2)降水与NDVI呈正相关关系,相关系数达0.74,降水在时间上呈波动上升趋势;3)耕地面积基本保持稳定,草地面积略有增加,水域面积和沙荒面积大幅减少,建设面积显著增加,林地面积占比最小,但增速最大;4)2020年所有土地利用类型中,耕地NDVI最大、贡献最大,沙荒最小。

In the Horqin Sandy Land,as an ecologically fragile area in northern China,the change of vegetation cover is affected by both climate change and human activities.With the NDVI data,precipitation records,and remote sensing interpretation results of land use from 2000 to 2020,using models such as gridded analysis,correlation analysis,and the land use transfer matrix,we quantitatively evaluates the driving mechanism of precipitation and land use changes on vegetation cover.The results show that:1)The vegetation cover index in the study area shows an upward trend(with a growth rate of 0.007 5 a^-1),and spatially,it presents a pattern where the Xiliao River Basin in the southeast and central parts is high,the north and south sides are relatively low,and the southwest is the lowest;2)There is a positive correlation between precipitation and NDVI with the correlation coefficient of 0.74,and the precipitation shows a wave-like increase over time;3)In the change of land use,the area of farmland remains basically stable,the area of grasses increases slightly,the areas of water bodies and sandy wasteland decrease significantly,the construction area increases remarkably,and the area of forest land accounts for the smallest proportion but has the largest growth rate;4)Among all land use types in 2020,the NDVI value of farmland is the largest,and that of sandy wasteland is the smallest.