arXiv subjects

Boris V. Kozelov

Publications and source records attributed to Boris V. Kozelov.

4 recordsLinked to original sources

arXiv2020

Retrieval of Particle Size Distribution of Polar Stratospheric Clouds Based on Wide-Angle Color and Polarization Analysis

The intensive polar stratospheric vortex in the Arctic that shifted to northern Europe in the winter of 2019-2020 caused low temperatures and the frequent occurrence of polar stratospheric clouds followed by a significant decrease in the total ozone content. Polarimetry and multi-color photometry using all-sky cameras in Lovozero (Murmansk Region, Russia, 68.0 deg N, 35.1 deg E) together with a new method of cloud field separation against the twilight background allowed for finding the light scattering characteristics related to the particle size distribution of polar stratospheric clouds. The results are compared with lidar and balloon experiments. The conditions of the appearance of visually bright polar stratospheric clouds of type I are discussed.

astro-ph.EP↗

arXiv2017

Detection of Molecular Scattering Field by Polarization Analysis of Sky Background During the Transitive Twilight and Temperature Measurements near the Stratopause

The simplest version of the method of detection of single molecular scattering basing on the polarization measurements of the twilight sky background by all-sky cameras is considered. The method can be used during the transitive twilight (solar zenith angles 94-98 degrees), when effective single scattering takes place in upper stratosphere and lower mesosphere. The application of the method to the multi-year measurements in the vicinity of Moscow and Apatity allows determination of temperature of these atmospheric layers and estimation of contribution and properties of multiple scattering during the transitive twilight period.

physics.ao-ph↗

arXiv2015

Noctilucent Clouds Polarimetry: Twilight Measurements in a Wide Range of Scattering Angles

Wide-field polarization measurements of the twilight sky background during the several nights with bright and extended noctilucent clouds in central and northern Russia in 2014 and 2015 are used to build the phase dependence of degree of polarization of sunlight scattered by clouds particles in a wide range of scattering angles (from 40 to 130 degrees). This range covers the linear polarization maximum near 90 degrees and large-angle slope of the curve which are most sensitive to the particle size. The method of separation of scattering on clouds particles on the twilight background is presented. Results are compared with T-matrix simulations for different sizes and shapes of ice particles, the best-fit model radius of particles (0.06 microns) and maximum radius (about 0.1 microns) are estimated.

physics.ao-ph↗

arXiv2015

Mesosphere Study by Wide-Field Twilight Polarization Measurements: First Results beyond the Polar Circle

The paper describes the observations and first results of studying the mesosphere temperature and dust based on twilight wide-field polarization analysis using original all-sky camera started in 2015 in Apatity, northern Russia (67.6 deg N, 33.4 deg E). It is the first twilight polarization measurements session conducted in the polar region and the first measurements during the winter and early spring season. The general polarization properties of twilight sky and the separation procedure of single scattering are described. The Boltzmann temperature decrease above 70 km and lack of mesosphere dust that is typical for this season are the key results of the study.

physics.ao-ph↗