I. D. Bryukhanov

Investigation of phase matrices of cirrus containing ensembles of oriented ice particles

Experimental results of polarization laser sensing of cirrus with anomalous backscattering are presented. The technique of determining the optical and geometrical characteristics of clouds is described. Experimental data are compared with the meteorological conditions at altitudes of cirrus above the lidar location and with the results of numerical modeling of phase matrices in the approximation of physical optics. The recurrence frequency of meteorological characteristics of “mirror” cirrus is estimated.

Study of influence of ice crystals orientation in cirrus on solar radiation transmission

The results of the investigation of radiation characteristics of cirrus consisting of crystalline ice particles with a preferred orientation are discussed. The orientation degree of particles is estimated from the backscattering phase matrices, which are determined with the high-altitude polarization lidar developed at National Research Tomsk State University. It is shown that the orientation of ice crystals in clouds with anomalously high backscattering affects significantly the transmission of solar radiation.

Effect of the orientation degree of crystalline ice particles in cirrus on the total flow of solar radiation in the photosynthetically active range

Results of complex experiments, in which flows of solar radiation are measured near the Earth’s surface in the presence of cirrus cloudiness and the orientation degree of ice crystals in cirrus is estimated using a polarization lidar, are discussed. Significant effect of the orientation degree of cirrus particles on the transmission of solar radiation is found in a number of experiments.

Optical properties of the cirrus cloud ice crystals with preferred azimuthal orientation for polarization lidars with azimuthal scanning

Optical properties of the cirrus cloud ice crystals with preferred azimuthal orientation are required for current numerical models of the Earths radiation balance. Retrieving the orientation distributions function of the crystals from a vertically pointing polarization lidar measuring the full Mueller matrix is a very complicated problem because of lake of information. Lidars with zenith scanning can be used only to retrieve the properties of horizontally oriented particles. The paper shows that if the particles have preferred azimuthal orientation, the polarization lidars with azimuthal scanning should be used. It is also shown that all the elements of the Mueller matrix give no extra information compare to the depolarization ratio. Optical properties of preferred azimuthal oriented hexagonal ice columns with size from 10 to 1000 μm for wavelengths of 0.355, 0.532 and 1.064 μm were collected as a data bank.

Laser polarization sensing of high-level clouds: problem of interpretation of experimental data

Joint analysis of the data on polarization laser sensing of cirrus obtained using the ground based polarization laser developed at National Research Tomsk State University (Russia, Tomsk) with the results of theoretical calculations is described. The possibility of estimation of the microstructure parameters of cirrus with a preferred orientation of ice crystals on the basis of comparison of the backscattering phase matrices obtained experimentally and calculated theoretically is discussed.

Determining the backscattering phase matrix of an aircraft condensation jet

Results of observation of the dynamics of evolution and decay of an aircraft condensation jet are described. Polarization lidar is used to determine the upper and lower boundaries of the aerosol layer, its optical thickness, scattering ratio, and backscattering phase matrix.

Polarization lidars with conical scanning for retrieving the microphysical characteristics of cirrus clouds

The paper presents the first results of observations of cirrus clouds by polarization lidars with conical scanning, which were developed in Hefei (China) and in Tomsk (Russia). The light scattering matrix of ice crystal particles of cirrus clouds has been calculated for the first by the authors within the framework of the physical optics approximations in the case of conical scanning lidar. It is found that in this case the Mueller matrix consists of ten non-zero elements, four of which are small and can’t be applied to interpret the azimuthal distribution of particle orientation. All the diagonal elements have a strong azimuthal dependence. Among the off-diagonal elements only one element M34 carries additional information for interpreting the azimuthal distribution.

Software for processing of experimental data on polarization laser sensing of high-level clouds

Methodology for determination of the optical and geometric characteristics of clouds is described. Problems of processing data obtained in experiments on polarization laser sensing of the atmosphere are discussed. Technique for reduction of the phase matrices of cirrus obtained with the high-altitude polarization lidar developed at National Research Tomsk State University to the symmetry plane affixed to the preferred orientation of ice crystals in cirrus is described. The experimental data are compared with the data of numerical modeling of phase matrices in the physical optics approximation and meteorological conditions over the lidar at cirrus altitudes.

Analysis of experiments on high-level cloud sensing with a satellite radiometer and a ground-based polarization lidar

We present results of joint analysis of the data of high-level cloud sensing with a polarization lidar and satellite radiometer MODIS. The possibility of detection from space of cirrus clouds with preferred orientation of ice crystals is discussed.