Vegetation dynamics in Ili River valley of Xinjiang based on MODIS/NDVI
16-day composite data set of normalized difference vegetation index (NDVI) from an moderate-resolu-tion imaging spectroradiometer(MODIS) was used to capture essential feature of temporal and spatial vegetation variability in Ili River valley of Xinjiang during the 2000-2010 period.Various statistical analyses involving vegetation anomaly index,linear regression analysis and Hurst index were applied.Examination shows as follows:(1) Vegetation cover of Ili River Valley increases firstly and then decreases as altitude increases,with highest vegetation cover located in the area with the altitude from 2 000 to 2 500 m.Generally,vegetation cover of different elevation zones of Ili River valley followed a decreasing trend during the period of 2000-2010,not including the areas located below 1 000 m above the sea level.(2)As vegetation anomaly index is subject to humidity of the air,so the highest spatially averaged vegetation anomaly index value was observed in the wettest year of 2000,and the lowest value in the driest year of 2008,and changes of vegetation anomaly index of different area exhibit varied patterns.(3) The areas with increasing or decreasing of vegetation cover account for 4.09％ and 19.34％ of the study region's total area,respectively.The increasing area's regions are mainly located at the plains of both banks of the Ili River.The decreasing area's regions are mainly located at the both ends of the Wusun Mountains and the low mountain areas surrounding the study region with the altitude of 2 000 m.Rescaled range analysis shows that changes of vegetation cover in the Ili River valley exhibits strong sustainability,which means that the change of vegetation cover will follow the same variation trend in the future some period in the Ili River valley.
国家科技期刊平台
NSTL
万方数据
维普
