Influence of soil moisture content on spectral reflectance of bare soils in the 0.4–14 μm domain

Abstract

A new semi-empirical soil model simulating the spectral signatures of bare soils in the optical domain 0.4–14 μm according to surface moisture content variation is presented and applied to several databases. The model specification is based on laboratory spectral reflectance measurements of many bare soils at different moisture contents. The measurement analysis leads to the definition of groups of bare soil samples according to their spectral behaviours. These laboratory measurements are made also to characterize the impact of soil moisture on spectral signatures (reflectance levels increasing with moisture content) and to give information on absorption peaks related to soil mineral components (hydroxyl, carbonate, and quartz). The procedure of modelling the spectral signatures of bare soil groups according to moisture content is discussed. The model is applied to a laboratory reflectance database and to the data available in the literature. The spectral reflectances, estimated with a semi-empirical model, compare favourably with reflectance observations.