Home – Home – Jornals – Advanced Search

The solar radiative fluxes in the cloudy and cloudless atmosphere are calculated taking into account multiple scattering and absorption. The cloudy conditions observed in Tomsk and Volgograd regions are considered. A comparison between the fluxes calculated with different water vapor continuum absorption models, such as the MT_CKD empirical model, commonly used in the atmospheric simulation, and the continuum model based on the CAVIAR experimental data, is carried out. The water vapor continuum impact on the shortwave radiative fluxes in the presence of different cloud types is estimated.

The possibility of determining the refractive index for optical waves in the atmospheric boundary layer from air temperature profiles measured by a MTP-5 meteorological temperature profilometer is studied. Profiles of the refractive index obtained from MTP-5 data and from aerological measurements are compared. Some calculated values of the refractive index and its derivatives for different seasons are presented.

Possible displacements of laser beams under the effect of regular refraction in the atmospheric boundary layer are calculated. The case of a radiation source installed at the surface level is considered. Displacements are estimated for different wavelengths and angles of the beam entrance into the atmosphere. The calculations are based on experimental data on the refractive index of optical waves up to an altitude of 1000 m received in long-term (one year) measurements of the vertical profiles of air temperature with a MTP-5 meteorological temperature profiler.

Quantitative estimates of the distribution of absorbed solar radiation and temperature effects in the background atmosphere and under conditions of extreme smoke haze in Siberia from empirical data and numerical modeling are presented. Vertical profiles of the aerosol characteristics are formed on the basis of an empirical model constructed from the results of airborne sounding of the angular scattering coefficient and the concentration of absorbing substance at different altitudes. It is shown that under smoke haze conditions the radiative effect of aerosol particles with a high soot content on the daily influx of solar radiation in the central part of the smoke layer exceeds 50%. The change in air temperature due to the absorption of solar radiation during the daylight time is approximately 2.5-5.5 K at variations in the smoke aerosol optical thickness in the range 2 £ _smoke(0.55 m) £ 4.

Mechanisms of glory (optical phenomenon observed on clouds) in view of new experimental aircraft researches of the cloud microphysics are considering. New data were received in research flights of ROSHYDROMET YAK-42D aircraft in polar and central regions of Russia. Data on the cloud particle size distribution are presented, and conditions of occurrence of glory on these clouds are discussed.

The variability of the optical-microphysical properties of the mixed wood smoke is studied in the Large Aerosol Chamber of IAO SB RAS (volume 1800 m³) during smoke aging for six days with periodic changes in the relative humidity of air within the range 45-95%. The dynamics of the size distributions and complex refractive indices for the ultrafine, fine, and coarse particles, their effective radii, lidar scattering parameter, and the single scattering albedo in the visible are analyzed on the basis of the results of detailed nephelometric measurements of the angular scattering coefficients and solution of the inverse problem. It is found that both quantitative and qualitative features of the variations in the optical-microphysical parameters vary significantly with the air humidity at different stages of the smoke aging. The key factors of the mixed smoke variability are the physical-chemical heterogeneity of three fractions of smoke particles and physical processes, such as migration of ultrafine BC particles (< 100 nm) in the size spectrum due to coagulation and the condensation growth of smoke particles. Interconnected effects (interference) of the mentioned processes on the particle’s structure determine the main features of the dynamics of the composition and absorbing properties of the smoke particles.

The Rayleigh-Gans-Debye and anomalous diffraction approximations are used to formulate necessary and sufficient conditions for optical equivalence of randomly oriented radially inhomogeneous optically “soft” ellipsoidal particles and polydisperse radially inhomogeneous spherical particles. The consequences of the optical equivalence are used as a basis for the optical classification of isotropic ensembles of “soft” ellipsoidal particles. Correctness of the classification is illustrated by the T-matrix method and Mie theory calculations.

A fundamentally new physico-mathematical formulation of the problem of retrieving the average field of atmospheric contaminant concentrations and detecting emission sources from local measurements is presented. This is a problem of passive location of the atmosphere by wind or a problem of fluid location of the atmosphere. The definitions of new functions are given: the mean effective concentration field and the mean effective field of the sources. The differential and integral forms of equations for the solution of the problem are presented. Several particular cases are briefly considered, which show the relationship of the proposed approach with the methods of back trajectories statistics and direct atmospheric dispersion simulation.

The comparative analysis of the chemical composition of water- and acid-soluble fractions in dry deposits is performed; the ratio of submicron and coarse phases in surface aerosols is assessed and their mineral and material composition are studied for the background region of Tom-Ob interfluve with use of the scanning submicroscopy. Distinctions in the ratios of metals in the water- and acid-soluble fractions are revealed. It is suggested that water-soluble compounds generally form the submicron fraction, and acid-soluble compounds, the coarse fraction.