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.
Application of MODIS in ocean color is mainly based on bands 8-16, whose spatial resolution is 1km. This spatial
resolution can't meet the demand of inland waters with small area. Then, taking TaiHu lake in China as an example, we
put forward an atmospheric correction algorithm for bands 1 and 2 whose spatial resolution is 250m. Firstly, we choose
one pixel whose digital number of band 16 is the smallest in Taihu lake as the clear pixel. The aerosol parameters of the
clear pixel are calculated by the standard atmospheric correction algorithm for Case 1 waters. Secondly, we can calculate
the aerosol scattering radiance of bands 1, 2 of other pixels with assumption that the aerosol type and optical thickness
keep the same over Taihu lake. This algorithm combines the advantage of bands 8-16 in ocean color atmospheric
correction with the high spatial resolution of bands 1 and 2. In order to test the precision of this algorithm, we choose an
MODIS-Aqua image which are covering Taihu lake and are acquired in the time of 2004 Taihu autumn cruise. We use
our atmospheric correction algorithm to process the selected image and compare the retrieved remote sensing reflectance
(Rrs) with measured Rrs. The average relative of bands 1 and 2 are respectively 24.85% and 41.44%, demonstrating that
this algorithm has the potential of application in the atmospheric correction of inland waters.