ass日本风韵熟妇pics男人扒开女人屁屁桶到爽|扒开胸露出奶头亲吻视频|邻居少妇的诱惑|人人妻在线播放|日日摸夜夜摸狠狠摸婷婷|制服 丝袜 人妻|激情熟妇中文字幕|看黄色欧美特一级|日本av人妻系列|高潮对白av,丰满岳妇乱熟妇之荡,日本丰满熟妇乱又伦,日韩欧美一区二区三区在线

It is an important way to understand the change of land resources and the environment by studying vegetation dynamic change and spatial-temporal evolution, which has important sense to improve the ecological environment scientifically. The spatial-temporal variation of vegetation cover in the Yellow River Basin was analyzed with mean method, variation coefficient method, trend analysis method and Hurst index, based on GIMMS-NDVI time series data (1982—2013). The results showed that the peaks of monthly average NDVI over the last 32 years were occurred mainly in the period of May to September from 1982 to 2013 in the Yellow River Basin, and the maximum was 0.546 in August. In annual variation, the vegetation cover had an increasing trend at the rate of 0.018/(10a). In the NDVI variation, the low fluctuation of NDVI was in leading position in the Yellow River Basin during 1982—2013, the area with variation coefficient less than 0.1 accounted for 53.88% of the total area. In spatial distribution of annual average of NDVI, the vegetation distribution pattern presented a stepped increasing trend from north to south. The area with mean annual of NDVI less than 0.4 accounted for 24.65% of the total area in the Yellow River Basin, and about 45.73% in better vegetation cover with mean annual of NDVI more than 0.6. In changing trend, as a whole, the vegetation cover showed a trend towards improvement over the last 32 years in the Yellow River Basin. Areas showing a trend towards improvement accounted for about 59.49% of the total area, and the area with no change accounted about 33.96%. In sustainable changes, the future changing type of vegetation cover would be unchanged and continuously improved, which accounted for 33.56% and 58.81% of the total area in the Yellow River Basin, respectively.