连江流域近18年来植被覆盖度变化分析

Changes of Vegetation Coverage During Recent18 Years in Lianjiang River Watershed

以TM影像为数据源,运用基于NDVI的像元二分模型,计算和分析连江流域1988和2006年植被演变特点及空间分布特征,并将两期影像的植被覆盖度图与连江流域分岩溶区地质图进行叠加,进而分析地质构造对植被覆盖度的影响。结果表明:①受气候及与人文因素的影响,1988～2006年连江流域植被覆盖度有所增加。表现为较高和高植被覆盖区面积增加,低、较低和中度植被覆盖区面积减少。②受地质构造影响,非岩溶区的植被质量优于岩溶区。③在空间分布上,近18 a来连江流域植被覆盖度的变化较显著。

With TM images as a data source,this paper calculates and analyses the characteristics of change and spatial distribution about the vegetation in Lianjiang watershed in 1988–2006 by using the dimidiate pixel model based on NDVI.Overlaying the vegetation coverage map and the sub-karst geological map,the impact on vegetation coverage exerted by geological structure is analyze.The results can be described in the following three aspects.1） Because of the effect of climate and human activities,the vegetation coverage in Lianjiang River watershed got a rise in 1988–2006.The area of higher and high vegetation coverage districts increased,while that of low,lower and middle vegetation coverage districts decreased.2） The quality of vegetation in non-karst district was better than that in karst district due to the influence of geological formation.3） The change of vegetation coverage＇s spatial distribution was significant in Lianjiang River watershed during the recent 18 years.