K. M. Firsov

Sensitivity of downward long-wave radiative fluxes to water vapor continuum absorption

An analysis of modern models of water vapor continuum absorption is presented. The sensitivity of downward long-wave fluxes to water vapor continuum absorption is investigated. The spectral intervals where continuum absorption is the most significant are defined. Recently discovered discrepancies between the model and experimentally measured absorption coefficients in the atmospheric transparency window of 8–12 μm are analyzed. It is shown that these discrepancies do not influence on calculation of long-wave radiative fluxes for the temperature range achievable in the Earth’s atmosphere.

Photophoretic motion of soot aerosols in field of shortwave solar radiation

The results of a theoretical analysis of the photophoretic motion of soot particles in the field of solar radiation under the conditions of stationary atmosphere are presented. In the refined radiation block of the model, integral fluxes of solar radiation were calculated by the Monte Carlo method in the context of the approximation of a plane-parallel horizontally homogeneous atmosphere. An analysis of the obtained results again verifies the possibility of significant photophoretic exhibitions for soot aerosol particles in the stratosphere; solar photophoresis can be considered an efficient mechanism of the vertical transport of absorbing submicron particles up to heights of the middle stratosphere. Forces of solar photophoresis can compete with forces of gravity up to heights of 30–35 km for particles of submicron and micron sizes. At the same time, the estimations again demonstrated the low efficiency of radiometric photophoresis for weakly absorbing, dense, and strongly heat-conducting particles of the atmospheric aerosol.

Total water vapor content retrieval from sun photometer data

Simulation of Sun photometer measurements for two regions of Russia is made and total water vapor content retrieval errors, caused by variations in meteorological parameters and the application of empirical formulas used in AERONET, are estimated.

Atmospheric radiation distributed information-computational system

The Atmospheric Radiation Internet-accessible distributed information-computational system is described. The system’s servers are located at the Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences (Tomsk); Volgograd State University; and Ural State University (Yekaterinburg). The information-computational system not only provides for access to data, but also allows for the calculation of the radiative characteristics of the Earth’s atmosphere. The system is aimed at investigations of the radiative transfer in the Earth’s atmosphere. The radiative models of the system are interesting for postgraduate students, students, and specialists in the area of atmospheric radiation and climate.

Calculation errors of the longwave fluxes in the Earth atmosphere due to the uncertainties of initial spectroscopic information

In the work an analysis of possible errors of the longwave radiative fluxes calculation due to spectroscopic uncertainties of HITRAN2004 database lines parameters and continuum models is carried out. Upper estimations of the fluxes calculation errors are founded. The errors are 0.2% for downward and 0.25% for upward fluxes. It is shown that the uncertainties of water vapor continual absorption may cause the fluxes error more then 1%, that exceeds the line parameters error. A comparison of the radiative fluxes calculated with different continuum models used in radiative codes is made.

The role of the water vapor continuum absorption in near ground long-wave radiation processes of the Lower Volga region

Analytical formulas for the estimation of the sensitivity of downward long-wave radiative fluxes to variations in the total water vapor content in the atmospheric vertical column in the absorption bands and atmospheric transparency windows are derived. The regression dependence of the CO2 radiative forcing on the total water vapor content is calculated for the Lower Volga region. The role of the H2O continuum absorption is studied, and the CO2 radiative forcing is shown to strongly depend on the continuum magnitude. The atmospheric conditions are determined, under which the contribution of the H2O continuum due to the interaction of water vapor with air molecules to the downward radiative fluxes is maximal.

Contribution of the Water Vapor Continuum Absorption to Shortwave Solar Fluxes in the Earth’s Atmosphere with Cirrus Cloudiness

The solar radiative fluxes in cloudy and cloudless atmospheres 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 using different models of water vapor continuum absorption, 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 impact of the water vapor continuum on the shortwave radiative fluxes in the presence of different cloud types is estimated.

Simulation of atmospheric radiative transfer using different ozone absorption cross-sections in the UV spectral region

Estimations of the effect of modern ozone absorption cros-ssections data on calculation of the atmospheric transmission and fluxes, measured using Sun photometers in the UV spectral region, are made. The ozone absorption cross-sections, often used in radiative codes, and new data of Serdyuchenko et al. are considered.

Atmospheric radiative transfer simulation in water vapor total content retrievals using different spectroscopic databanks of H2O absorption line parameters

Simulation results for atmospheric absorption spectra of solar radiation in spectral intervals, where measurement of H2O content can be carried out, are presented. A comparison with the measured atmospheric transmission spectra of solar radiation is made. The water vapor total column is retrieved from the measured atmospheric spectra with the use of different spectroscopic databanks of H2O absorption lines under various atmospheric conditions and solar zenith angles.

Comparison of two water vapor continuum models in simulation of the longwave fluxes taking into account absorption in cirrus clouds

The longwave radiative fluxes were simulated using different water vapor continuum models for meteorological conditions of Tomsk and Volgograd. The atmosphere with various temperatures, water vapor contents and optical depths of cirrus clouds was considered. The contribution of uncertainties in the continuum models to simulation of downward and upward longwave fluxes is estimated.