基于RS的近30年滹沱河流域植被覆盖度动态变化研究

RS-Based Study on Dynamic Change of Vegetation Coverage in Hutuo River Watershed in the Past 30 Years

以滹沱河流域1984年、2001年和2014年3期遥感影像为数据源,基于像元二分模型,利用归一化植被指数(NDVI)反演流域植被覆盖度信息,分析了滹沱河流域近30年来植被覆盖度时空演变特征及其变化原因。滹沱河流域近30年来植被覆盖度总体呈增加趋势,其中高植被覆盖度区面积比例增幅最明显,增加了1.1倍。空间分布上,受气候和人类活动双重因素影响,流域不同区域植被覆盖度变化差异较显著,上中游植被总体以改善为主,海拔相对较低的区域则表现为退化,尤其是下游植被覆盖度持续下降,植被退化面积占该区的71.52%。

With the remote sensing images in 1984,2001 and 2010as data source,based on the dimidiate pixel model,the Normalized Difference Vegetation Index（NDVI）was used to deduce the information of vegetation coverage.And the paper analyzed the characteristics of spatio-temporal evolution about vegetation coverage for Hutuo River watershed in the past 30 years and the reasons for the change.Results showed that the vegetation coverage for Hutuo River watershed in the past 30 years showed ageneral increasing trend,and the increase in high vegetation coverage area proportion was the most obvious,with an increase of1.1times,from 18.23%in 1984 to 38.31%in 2014.In the spatial distribution,affected by the dual factors of climate and human activities,the vegetation coverage changes in different regions showed more significant difference.The vegetation of upstream and midstream mainly improved on the whole,and the area in a relatively low altitude showed degradation.Especially the downstream vegetation coverage continued to decline,and the degraded area accounted for 71.52% of this area.