tailieunhanh - Tán xạ của sóng điện từ P6

Radiative transfer theory is an important method to treat multiple scattering in medium consisting of random discrete scatteries. Classic books on the subject include Chandrasekhar [1960]; Ishimaru [1978]; Case and Zweifel [1967]. The theory has been extensively applied [Tsang et al., 1977; Tsang et al. 1985; Fung, 1994; Ulaby et al. 1990; Burke et al. 19791. | Scattering of Electromagnetic Waves Theories and Applications Leung Tsang Jin Au Kong Kung-Hau Ding Copyright 2000 John Wiley Sons Inc. ISBNs 0-471-3879C-1 Hyrdbac2 0-471-22428-6 Electronic Chapter 7 RADIATIVE TRANSFER THEORY 1 Scalar Radiative Transfer Theory 260 2 Vector Radiative Transfer Theory 269 Phase Matrix of Independent Scattering 269 Extinction Matrix 272 Emission Vector 275 Boundary Conditions 283 References and Additional Readings 286 - 259 - 260 7 RADIATIVE TRANSFER THEORY Radiative transfer theory is an important method to treat multiple scattering in medium consisting of random discrete scatteries. Classic books on the subject include Chandrasekhar I960 Ishimaru 1978 Case and Zweifel 1967 . The theory has been extensively applied Tsang et al. 1977 Tsang et al. 1985 Fung 1994 Ulaby et al. 1990 Burke et al. 1979 . In this chapter we derive the equation that governs the propagation of specific intensity in a medium containing random distribution of particles. The particles scatter and absorb the wave energy and these characteristics should be included in a differential equation to be satisfied by the specific intensity. This equation is called the radiative transfer equation. There are three constituents of the radiative transfer equation. The extinction matrix describes the attenuation of specific intensity due to absorption and scattering. The phase matrix characterizes the coupling of intensities in two different directions due to scattering. The emission vector gives the thermal emission source of the specific intensity. Since the specific intensity is a four-element Stokes vector the extinction and phase matrices are 4x4 matrices and the emission vector is a 4 x 1 column matrix. For spherical particles the extinction matrix is diagonal and is a constant times the unit matrix. The emission vector has the first two elements equal and the last two elements equal to zero. For non-spherical particles the extinction matrix is generally .