基于NDVI的新疆植被覆盖变化特征分析

Characteristics of Vegetation Cover Change in Xinjiang Based on NDVI

新疆植被生态系统较脆弱,是长期保护和关注的重点区域。借助GEE平台获取了由美国航空航天局提供的归一化植被指数(NDVI)数据,采用均值法、差值法、趋势分析法、稳定性分析法、Hurst指数等方法,多角度对2000—2021年新疆生长季(4—10月)植被覆盖时空变化和未来趋势进行了研究。结果表明:1)近22年来新疆植被覆盖总体呈不显著上升趋势,以每年0.0014的变化速率略有增长,在空间分布表现为北部和西北部高,南部和东南部低;2)新疆植被覆盖变化呈增加趋势面积占85.2%,呈减少趋势面积占14.8%,显著增加地区分布在塔城地区、伊犁哈萨克自治州、巴音郭楞蒙古自治州北部和盆地周边的绿洲;显著减少的地区分布在石河子市、乌鲁木齐市、喀什市、和田市等;3)近22年来新疆植被覆盖变化波动明显,Hurst指数均值为0.44,反向持续性较强,未来需要进一步加强植被生态修复和防护工作。

The vegetation ecosystem in Xinjiang is fragile,which is the key area for long-term protection and attention.With the help of GEE platform,the normalized vegetation index(NDVI)data provided by NASA were obtained,and the spatial-temporal changes and future trends of vegetation cover in Xinjiang during the growing season(April to October)from 2000to 2021were studied by means of means method,difference method,trend analysis method,stability analysis method,Hurst index and other methods.The results showed that,1)the vegetation coverage in Xinjiang showed a slight increase at the rate of 0.0014each year in the past 22years,with a higher spatial distribution in the north and northwest and a lower spatial distribution in the south and southeast.2)In Xinjiang,85.2%of the vegetation cover increased,while 14.8%of the vegetation cover decreased.The vegetation cover increased significantly in Tacheng Area,Yili Kazak Autonomous Prefecture,northern Bayingolin Mongolian Autonomous Prefecture and the oases around the basin.The significant decrease was found in Shihezi,Urumqi,Kashgar,Hotan,etc.3)In recent 22years,the vegetation coverage in Xinjiang fluctuates significantly.The average hurst index is 0.44,indicating strong reverse persistence.Therefore,ecological restoration and protection of vegetation should be further strengthened in the future.