Since 1987 the thermal emission from crop canopies has been measured by multi-frequency microwave radiometers designed by Changchun Institute of Geography

Academia Sinica. The relationship between dualpolarized brightness temperature and some related parameters

such as crop height

moisture content

geometric structure

etc.

has been experimentally obtained. To quantitatively understand the functional dependence of brightness temperature on those parameters and frequency

polarization

observation angle

we have developed a numerical modeling of radiative transfer for multi-layer random media

which modeled the stratified layers of fruit

leaves and stalks. The newly-derived dual-dispersion model and Polder Van/de Loor formulation are used to calculate the mean dielectric permittivity. All parameters are chosen in a consistent way. The radiative transfer equation for multi-layer random media is derived. By using the discrete-ordinate and eigen analysis methods

numerical results of radiative transfer are obtained

and are favorably compared with the experimental data. The functional relationship between the brightness temperature and various parameters are discussed.