山地遥感生态指数的构建及应用

Construction and application of hilly remote sensing ecological index

山地丘陵地区是国家生态安全屏障的主体之一。为避免地形起伏对其生态质量评价产生影响,本研究采用归一化差值山地植被指数(NDMVI)作为绿度生态因子,结合湿度、干度和热度构建基于遥感生态指数(RSEI)改进的山地遥感生态指数(HRSEI),并对典型山地丘陵区福建省龙岩市长汀县和陕西省商洛市山阳县开展生态质量评价,对比HRSEI和RSEI的生态质量等级转移路径,验证HRSEI在山地区域的适用性。结果表明:NDMVI相较于NDVI在山地区域能提取到更多的植被信息,地形起伏越大,NDMVI提取植被信息的能力越强。经过平均相关度和逐步回归方程验证可知,采用HRSEI对山地丘陵区域的生态质量评价具有代表性。HRSEI主要将部分受阴影干扰的植被生态等级从良提升为优,与RSEI的提取结果相比,长汀县和山阳县生态等级为优的面积分别提升了13.75和41.88 km^(2)。结合高分辨率影像可知,生态质量提升的范围对应为被山地阴影影响的高植被覆盖区,说明HRSEI可以有效提升受阴影影响的高植被覆盖区的识别准确度,使其更符合实际。

Mountainous and hilly regions are one of the mainstays of national ecological security barriers.To avoid the impact of terrain undulations on the ecological environment quality assessment,we used the normalized difference mountain vegetation index(NDMVI)as the greenness ecological factor,combined with the humidity,aridity,and thermal factors,to construct the improved the hilly remote sensing ecological index(HRSEI)for mountainous areas based on the remote sensing ecological index(RSEI).We assessed ecological quality in two typical mountai-nous and hilly areas,i.e.,Changting County in Longyan City,Fujian Province,and Shanyang County in Shangluo City,Shaanxi Province.We compared the ecological quality grade transition paths of HRSEI and RSEI,and verified the applicability of HRSEI in mountainous areas.The results showed that NDMVI could extract more vegetation information in mountainous areas than NDVI.The greater the topographic relief,the stronger the ability of NDMVI to extract vegetation information.Verified through average correlation and stepwise regression equations,HRSEI was representative for the ecological quality assessment of mountainous and hilly areas.HRSEI mainly upgraded the vegetation ecological grade from good to excellent for some areas affected by shadows.Compared with the extraction results of RSEI,areas classified as excellent increased by 13.75 and 41.88 km^(2) in Changting and Shangyang,respectively.Combined with high-resolution imagery,the areas with improved ecological quality corresponded to high-vegetation-cover areas affected by mountain shadows,indicating that HRSEI could effectively improve the identification accuracy of high-vegetation-cover areas influenced by shadows,making it more practical.