The peculiarities are considered of variations of the spectral behavior of the extinction and backscattering coefficients and lidar ratio (on the one hand), and microphysical characteristics of aerosol particles, represented by the complex refractive index and particle size distribution function (on the other hand). It is shown, based on Mie-theory calculations for mono- and bimodal distributions that the Angstrom parameters for the extinction coefficients provide for information about the contribution of small particles Vf /Vt into the volume concentration, and weakly depend on the mean geometric radius of small particles Rf. On the contrary, the Angstrom parameters for the backscattering coefficients provide for information about Rf and are practically independent of Vf /Vt. The lidar ratio and the Angstrom parameters for the backscattering coefficient strongly depend on the real mR and imaginary mI parts of the refractive index. Restriction of the range of variations of the lidar ratio leads to restriction of the range of variations of ml (mR is fixed), which is shifted to the range of greater values ml, when mR increases. The increase of the lidar ratio with wavelength can be observed only for the large particles at Vf /Vt < 0.2 and the values of the real part of the refractive index ~1.40.
Mie-theory, Angstrom parameters, extinction and backscattering coefficients, lidar ratio, refractive index, particle size distribution