不同植被指数反映地表植被覆盖度的比较分析——以甘肃河西走廊地区为例

Comparative Analysis on the Reflection Effect of the Vegetationon the Earth's Surface by Different Vegetation Indices:A Case Study in Hexi Corridor

针对不同的地表植被覆盖情况,以期合理精准的选择植被指数反映地表植被效果给予一定的技术支持,选择甘肃省河西走廊地区为研究对象,基于甘肃省MODIS影像数据,借助ERDAS、ArcGIS地图处理软件及SPSS统计分析软件对不同植被指数(NDVI、PVI、RVI)反映地表植被覆盖度的效果进行了比较研究。分析结果显示:河西走廊北部东中西3段的以NDVI值估算的植被覆盖度分别为0.33、0.31、0.42,祁连山西中东3段分别为0.62、0.62和0.37,进而研究PVI和RVI与不同植被覆盖度区域相关性。经研究分析得出:对于高盖度植被覆盖地区,RVI所反映的植被覆盖度明显优于PVI;对于低盖度植被覆盖地区,由于PVI受土壤背景(质地、亮度)和大气影响较小,比RVI更能反映荒漠等沙粒质地表区域。

According to the different coverage of the surface vegetation, the study chose the reasonablevegetation index to reflect the effect of vegetation, and gave a certain technical support. Selected Hexi Corridorin Gansu Province as study area, the paper studied the correlation between different vegetation indices（PVI and RVI） and vegetation coverage, which was based on the NDVI value. The results showed the value of NDVI,the estimated vegetation coverage in the east, middle and west sections in the northern Hexi Corridor were0.33, 0.31 and 0.42 respectively, the NDVI in the east, middle and west sections in the Qilian Mountains were0.62, 0.62 and 0.37. The correlation between the PVI, RVI and different vegetation coverage indicated that theeffect of RVI on reflecting the vegetation coverage in the high vegetation coverage area was significantly betterthan the effect of PVI. However, in the low vegetation coverage area, PVI was better than RVI because it canreflect the grain of sand nature of surface such as desert due to the little influence come from the soilbackgroundsuch as brightness and substance, and atmosphere.