Development of broadband albedo based ecological safety monitoring index

Abstract

Normalized difference vegetation index (NDVI) plays an important role in the detection of drought and desertification. However, being calculated by direction limited spectral reflectance, it is almost ignorant to anisotropy of target reflection. In this paper, on the basis of atmospheric correction of Landsat-7 Enhanced Thematic Mapper Plus (ETM+) data using 6S (Second Simulation of Satellite Signal in the Solar Spectrum) code, bidirectional reflectance distribution function (BRDF) of surface coverage is obtained to retrieve spectral albedos of certain wavelengths. Narrowband spectral albedo to broadband albedo conversion is accomplished via measured band data and simulation of unknown spectral wavelengths which are not available by Landsat-7 ETM+ imagery. Albedo based ecological safety monitoring index (ESMI) is developed and sensitivity analysis of ESMI in surface application is conducted. Application results show that ESMI has potential use in quantitative monitoring of eco-environmental problems