Observations of specular reflective particles and layers in crystal clouds.

In the present article, results of observations of high crystal clouds with high spatial and temporal resolution using the ground-based polarization LOSA-S lidar are described. Cases of occurrence of specularly reflective layers formed by particles oriented predominantly in the horizontal plane are demonstrated. Results of measuring echo-signal depolarization are compared for linear and circular polarization states of the initial laser beam.

Reconstruction of the aerosol optical parameters from the data of sensing with a multifrequency Raman lidar.

A method of interpreting data of multifrequency Raman lidar sensing is developed. An algorithm for separating aerosol layers with different scattering properties and subsequently estimating the average value of the lidar ratio and Angström parameter within individual layers is suggested. The algorithm allows the error of reconstructing the backscattering coefficient from daytime observations to be at least halved. A well-posed numerical differentiation algorithm for determining the extinction coefficient is suggested for the interpretation of nighttime measurements based on the transformation of the range of allowable values that requires a solution of nonlinear equations. An iterative procedure envisaged for linearization improves the spatial resolution compared with the conventional methods. The methods can be successfully used to process routine lidar measurements under conditions of a priori uncertainty.

Method for reconstructing atmospheric optical parameters from the data of polarization lidar sensing.

Inversion of polarization lidar sensing data based on the form of the lidar sensing equation with allowance for contributions from multiple-scattering calls for a priori information on the scattering phase matrix. In the present study the parameters of the Stokes vectors for various propagation media, including those with the scattering phase matrices that vary along the measuring range, are investigated. It is demonstrated that, in spaceborne lidar sensing, a simple parameterization of the multiple-scattering contribution is applicable and the polarization signal's characteristics depend mainly on the lidar and depolarization ratios, whereas differences in the angular dependences of the matrix components are no longer determining factors. An algorithm for simultaneous reconstruction of the profiles of the backscattering coefficient and depolarization and lidar ratios in an inhomogeneous medium is suggested. Specific features of the methods are analyzed for the examples of interpretation of lidar signal profiles calculated by the Monte Carlo method and are measured experimentally.