Vegetation Indices of High and Low Vegetation Density Areas in Southern Part of Taklimakan Desert

タクラマカン

[ABSTRACT] In estimating the vegetation coverage from NDVI (Normalized Vegetation Index, Rouse et. al., 1974) or SAVI (Soil Adjusted Vegetation Index, Huete, 1988) which are calculated from the satellite data, the vegetation density within a pixel affect the results. To eliminate this undesirable effect, an optimum vegetation index (OPVI) is presented in this paper In this method, the vegetation coverage within each pixel is calculated from the reflectance ratio of radiance in TM 5 band to that in TM 7 band. Then, if the reflectance ratio is larger or smaller than a critical value, we select either NDVI or SAVI for calculating the vegetation index in each pixel. In this case, the critical value must be set in advance. For determining the critical value, the relationship between vegetation coverage and the reflectance ratio are studied from the spectral reflectance of plants and soils as a function of ratio of coverage area of plants to that of soils in the laboratory. Then, the critical value is determined by comparing the results obtained by NDVI and SAVI. Comparison of results obtained by OPVI method with those by both NDVI and SAVI are made by using the satellite data collected in and around oases in Taklimakan Desert in China since the vegetation is expected to vary over the wide range. The results show that OPVI gives a better indicator of actual vegetation cover in an arid area than single NDVI or SAVI alone.

https://opac.ll.chiba-u.jp/da/curator/900022226/

https://opac.ll.chiba-u.jp/da/curator/900022226/C-18_31.pdf

Chiba University. Center for Environmental Remote Sensing

千葉大学環境リモートセンシング研究センター

会議発表用資料

BA40894043

Proceedings of the CEReS international symposium = CEReS国際シンポジウム資料集

2

193

200

1997-01-29

publisher

環境リモートセンシング研究センター「CEReSシンポジウム資料集」