Spatial difference of MODIS-NDVI variations in Gasikule Lake basin,Qaidam from 2000 to 2011

Base on RS and GIS technology,the spatial difference of NDVI variations in Gasikule Lake basin was analyzed and the results showed that the greening area,stable area,degraded area and bare area accounted for 17.64%,37.31%,0.57%and 44.48%of the total area respectively in the variation trend of vegetation NDVI maxima.The greening area,stable area,degraded area and bare area accounted for 31.11%,24.09%,0.36%and 44.48%of the total area respectively in the variation trend of growing-season vegetation NDVI averages.In the past 12 years,vegetation NDVI maxima in mountainous regions had a significant growth trend and growingseason vegetation NDVI averages in the mountainous region had a nonsignificant trend;vegetation NDVI maxima in the oasis region had a significant growth trend and the growing-season vegetation NDVI averages in the oasis region had a nonsignificant trend.In all the altitude rings,the bigger the NDVI value,the more intense the vegetation greening trend;the smaller the NDVI value,the weaker the vegetation greening trend.In all altitude rings,the area percent of every variation trend was of single-peak form.The peak values appeared in turn from greening area,table area to degraded area.Greening area was mainly distributed in gentle slopes while degraded area was mainly distributed in steep slopes.The area percent of greening area and table area in the north slopes was maximum while the area percent of degraded area in north slope was minimum.