Shuiyun And Cirrus Radiation Parameters

This paper described light scattering and absorption by single particles, optical properties of water clouds and cirrus, single-scattering properties of ice particles in cirrus and phase function in radiative transfer. The main methods in current research are classical Mie, FDTD, T-MATRIX, Lorenz-Mie and IGOM. Some useful results are listed as follow:(1) The main methods in Mie scattering calculation were fully discussed. Present a new formula to evaluate the overflow value when upward recursion was used and an improved formula when downward recursion was used.(2) The single-scattering of water clouds was calculated by integrating Mie theory and particles distribution function. The result was also compared with existed table and proved the new composite scheme is efficient.(3) The single-scattering property of water clouds was calculated by Polynomial Fitting and we could see the relative error is less than 10% in solar and even less than 3% in infrared.(4) The composite scheme was adopted to calculate the scattering property of six kinds of ice particles, including solid and hollow columns, spatial bullet-rosettes, aggregates, droxtals and plates, based on FDTD, T-MATRIX, IGOM and Lorzen-Mie. A single-scattering database for six kinds of ice particles was created. Each of files includes extinction efficiency, single-scattering albedo, asymmetry factor and phase function at 65 wavelength bins and 45 size bins at every wavelength and 498 discrete values of phase function at every wavelength and size.(5) Created a single-scattering database for cirrus. The database includes all single-scattering properties of cirrus. The database is valid at wavelength from 0.4 micron to 2.2 micron and the effective dimension from 10 micron to180 micron.(6) Present a new parameterization scheme for cirrus by using IWC(Ice Water Content) and effective dimension. The new scheme is efficient at wavelength from 0.4 micron to 5 micron.(7) It proved that theδ-fit method is best fitting for phase function by comparing the result with traditional Legendre Polynomial expansion technique and Delta-M method.