黄河三角洲植被覆盖遥感估算及变化分析

Estimation and Analysis on Dynamic Changes of Vegetation Coverage in Yellow River Delta

植被覆盖度是重要的生态环境参数之一。文章以黄河三角洲为例,运用归一化植被指数(NDVI)和像元二分模型对黄河三角洲地区2004年和2010年的植被覆盖度进行了估算,将黄河三角洲植被覆盖划分为4个等级:低植被覆盖区、中植被覆盖区、高植被覆盖区和全植被覆盖区,并分析其变化趋势。结果表明,低植被覆盖区面积最大,主要位于沿海、中部地区和黄河以南,中植被覆盖区主要位于北部沿海地区,全植被覆盖区主要位于黄河及其支流沿岸。从植被覆盖变化趋势看,2004-2010年间低植被覆盖区、中植被覆盖区和全植被覆盖区面积都有所减少,其中低植被覆盖区减少面积最大,达312.39km2,全植被覆盖区面积变化幅度最大,变化率为76.8%。高植被覆盖区面积增加了352.31km2,变化率为30.6%。利用NDVI植被指数和像元二分模型对黄河三角洲地区植被覆盖度进行遥感估算,可以快速有效地分析不同时期的植被覆盖变化,方法简单可行,结果可为黄河三角洲地区水土保持和生态环境保护政策制定提供依据。

The vegetation coverage is one of the important ecological parameters.Remote sensing image can reflect the information and its trend of vegetation coverage at different spatial scales.So the remote sensing monitoring is an important means of obtaining the regional vegetation coverage parameters.In this paper,the normalized difference vegetation index（NDVI） and two sub-pixel model were used on the vegetation coverage estimation of the Yellow River Delta.And the dates of the Yellow River Delta in September 2004 and September 2010 were used to conduct a longitudinal comparison.The result indicated that the high vegetation cover distribution was more concentrated in the northwest and eastern regions,and the middle vegetation cover was mainly distributed in the northern coastal areas;the high coverage of the vegetation of the region was distributed in the northwest and along the Yellow River , while the vegetation coverage of the south bank was low;the vegetation coverage of coastal areas was low ,while the vegetation coverage of the inland was high.The areas of low vegetation coverage,the middle vegetation coverage and the full vegetation coverage reduced from 2004 to 2009 obviously.The regions with high have increased with the changing rate of 30.6%.