Polarized reflectance characteristics of plant canopies including atmospheric aerosol optical properties

This paper presents a large set of spectral and directional signatures of the polarized reflectance acquired over various plant canopies in different atmospheric conditions. An instrument has been developed for measuring the BPDF (Bidirectional Polarization Distribution Function) of plant canopies in the field. Polarized multi-wavelength analytical physically-based model was developed. For the analysis of polarization measurements studied, it is found that although spectral variations in the polarized reflectance are observed, the ratio of the two wavelength polarized reflectance is stable. The ratio is related to atmospheric aerosol optical depth. Our results also suggest that using the correlation between the polarized reflectance of the short wave infrared band (SWIR) with those in the visible rang can eliminate the effect which caused by the plant canopies geometric structure. On the other hand, since the model accurately predict the polarized reflectance relations between the short wave infrared bands and the visible rang, they can be used to discriminate the aerosol contribution from the surface of the plant canopies cover in the retrieval procedure. © 2009 Copyright SPIE - The International Society for Optical Engineering.