Inelastic High-Energy Electron Spectrafrom Plane-Parallel Layer-Nonhomogeneous Surfaces

We consider inelastic backscattering of electrons with initial energy of tens and hundreds of keV by plane-parallel homogeneous and sandwiched targets. Basing on the invariance principle, we find expressions that describe the dynamics of the changes in the energy spectra of electrons reflected into a given solid angle that occur with increase of the thickness of films of different materials on substrates of finite and infinite thickness. We substantiate a procedure of linearizing the equations for the reflection function obtained by the method of invariant imbedding. We obtain an analytical solution of linearized equations in the form of a series in Legendre polynomials. A comparison with experimental data shows that the theory developed gives an adequate description of the process of electron backscattering.

Microwave Brightness of Polar Firn as Measured by Nimbus 5 and 6 ESMR

The microwave emission from a half-space medium characterized by coordinate dependent scattering and absorbing centers has been calculated by numerically solving the radiative transfer equation by the method of invariant imbedding. A Mie scattering phase function and surface polarization have been included in the calculation. Also included are the physical temperature profile and the temperature variation of the index of refraction for ice. Using published values of grain-size and temperature-profile data of polar firn, the brightness temperature has been calculated for the 1.55 cm and 0.8 cm wavelengths. For selected regions in Greenland and Antarctica, the results of our calculations are in reasonable agreement with the observed Nimbus-5 and Nimbus-6 ESMR data.

Microwave Brightness of Polar Firn as Measured by Nimbus 5 and 6 ESMR

The microwave emission from a half-space medium characterized by coordinate dependent scattering and absorbing centers has been calculated by numerically solving the radiative transfer equation by the method of invariant imbedding. A Mie scattering phase function and surface polarization have been included in the calculation. Also included are the physical temperature profile and the temperature variation of the index of refraction for ice. Using published values of grain-size and temperature-profile data of polar firn, the brightness temperature has been calculated for the 1.55 cm and 0.8 cm wavelengths. For selected regions in Greenland and Antarctica, the results of our calculations are in reasonable agreement with the observed Nimbus-5 and Nimbus-6 ESMR data.