1998—2012年黄河流域植被覆盖变化时空分析

 利用黄河流域1998—2012年SPOT-NDVI数据及同期119个气象站的降水数据，计算每个像元的NDVI变化趋势，并结合植被降水利用效率来分析近15年来黄河流域植被覆盖的时空变化特征。结果表明：（1） 多年平均的植被指数有明显的空间差异性，随着纬度的增加，NDVI平均值呈降低趋势；（2） 从时间序列来看，黄河流域的植被覆盖呈逐年增加趋势，其中黄河上游NDVI值增长最为缓慢，中游保持稳定增长，下游增长最快；（3） 近15年来黄河流域植被覆盖的改善区域面积大于退化区域，植被恢复明显。最后，结合NDVI变化趋势和植被降水利用效率对上述结果进行了验证。

The Spatial-temporal Changes of Vegetation Restoration in the Yellow River Basin From 1998 to 2012

According to the time-series NDVI data from 1998 to 2012 and the precipitation data from 119 Weather stations around the study area,calculate the changes of vegetation cover from 1998 to 2012 years in the Yellow River Basin,and combined with RUE to analyzes the main characteristics,temporal-spatial distribution and changes of vegetation restoration from 1998 to 2012 years in the Yellow River Basin. Results shows: (1) the average vegetation cover exhibited spatial heterogeneity.With the increase of latitude,the average NDVI showed a trend of decrease; (2) The value of NDVI had a fluctuation change trend during the past 15 years,but on the whole there still was a significant increased trend of vegetation cover in the Yellow River Basin.The trends of the upper basin increased slowly,the middle basin keep quiet,the lower basin increased quickly; (3) The area of vegetation degradation region less than vegetation recovery region in the Yellow River Basin during the past 15 years. Finally, combined NDVI and PUE to identify the conclusion.