以2000—2015年MODIS-NDVI动态数据为基础,辅以小波分析、趋势分析、变异系数、Hurst指数及空间叠加分析等方法,探究怒江流域(云南区段)近16年植被覆盖时空分布,变化特征和演变趋势。结果表明:1)时间上,流域NDVI月际变化整体呈增长态势,月均增长率为0.95%;在年际变化方面,流域植被覆盖呈现增长趋势且存在14年左右的变化周期,增速为0.21/10a;月际和年际增长趋势均通过置信度P<0.05的显著性检验。2)空间上,流域高植被覆盖区域(0.6<NDVI<1)占61.95%,整体较好。受北部高海拔地形以及南部建设用地扩张等因素影响,植被覆盖格局从北至南呈低—高—低的分布特征。2000—2015年间,流域植被覆盖整体处于低态势波动变化,低波动和较低波动变化区域占比合计83.18%,在该波动下约53.25%的区域植被覆盖得到了改善,14.41%,32.34%的区域植被分别呈退化及不变趋势。3)空间可持续性方面,约59.01%的区域植被将延续过去变化趋势,37.98%的区域植被将沿反向发展,同向特征强于反向特征。未来,植被覆盖将向良性、不变方向发展的区域分别占39.36%,26.50%;31.14%的区域植被覆盖将向不利方向发展,主要集中于南部各县(市)中心、外围等城镇建设用地区以及勐波罗河、枯柯河、勐统河等支流沿线区,需引起重视。

The spatio-temporal distribution,characteristics of variation and evolutionary trends of vegetation cover of Nujiang River basin in Yunnan Province during the period 2000—2015 were analyzed with wavelet analysis,Trend analysis,Cv methods and Hurst index based on MODIS-NDVI dynamic data.The results showed that:(1)From the temporal variation,the monthly variation of NDVI in the basin showed an overall growth trend,with an average monthly growth rate at 0.95%.For the annual variation aspect,the vegetation cover had an increasing trend at the rate of 0.21/(10 a),and there is a change period of about 14 years,which were obtained through the inspection by a significant level of 0.05.(2)For the spatial aspect,the high vegetation coverage area (0.6<NDVI<1)in the river basin accounts for 61.95%,which is better overall.Influenced by factors such as high-altitude terrain in the north and expansion of construction land in the south,the pattern of vegetation cover showed low-high-low distribution characteristics from north to south.In the last 16 years,the overall vegetation cover was in a low-level fluctuation,with low fluctuation region and lower fluctuation region accounting for 83.18%.Based on this fluctuation,areas showed a trend towards improvement accounting for about 59.49% of the total area,and 14.41% and 32.34% of the regions showed degenerate and unchanging trend.(3)For the spatial sustainability aspect,about 59.01% of the regional vegetation will continue the trend of the past,and 37.98% will develop in the reverse direction,Co-directional features are stronger than reverse features.In the future change of vegetation cover,regions with the invariable and benign development directions of vegetation,occupy 26.50% and 39.36%,and 3.14% of the regions,which will develop in a unfavorable direction,and be mainly distributed in the urban construction areas such as the center and periphery of the southern counties (cities)and the areas along the tributaries such as the Meng Baltic River,Kuke River and Mengtong River,which needs to be taken seriously.