An improved model of radiative transfer for the NLTE problem in the NIR bands of CO<Subscript>2</Subscript> and CO molecules in the daytime atmosphere of Mars. 1. Input data and calculation method     

V. P. Ogibalov  G. M. Shved 《Solar System Research》2016,50(5):316-328

Advances in attacking the problem of radiative transfer in the near infrared (NIR) bands of CO₂ and CO under nonlocal thermodynamic equilibrium (NLTE) conditions depend on the accuracy of taking into account the radiation processes and inelastic collisions of CO₂ and CO molecules. The focus of the paper is to substantially improve the physical model of the problem and update the calculation method. It is the first time the surface albedo is introduced into the problem of the molecular emission under NLTE conditions. The values of the rate constants for inelastic molecular collisions and their temperature dependences have been radically updated. In some cases, since laboratory measurements of these constants are lacking, different versions are provided for them. The relative abundance of CO₂ and CO isotopologues is based on the ratios of isotope abundances for the elements C and O obtained from the measurements in the atmosphere of Mars. The intensity of extraterrestrial solar NIR radiation is specified on the base of the high-accuracy ground-based measurements. In the method for calculating the populations of vibrational states, we pioneer in completely taking into account the overlapping of spectral lines in the NIR bands of CO₂ and CO.  相似文献   

An improved model of radiative transfer for the NLTE problem in the NIR bands of CO<Subscript>2</Subscript> and CO molecules in the daytime atmosphere of Mars. 2. Population of vibrational states     

V. P. Ogibalov  G. M. Shved 《Solar System Research》2017,51(5):373-385

The near-infrared (NIR) emission of the Martian atmosphere in the CO2 bands at 4.3, 2.7, 2.0, 1.6, 1.4, 1.3, 1.2, and 1.05 µm and in the CO bands at 4.7, 2.3, 1.6, and 1.2 µm is mainly generated under nonlocal thermodynamic equilibrium (NLTE) conditions for vibrational states, the transitions from which form the specified bands. The paper presents the results of simulations of the population of these states under NLTE for daytime conditions. In the cold high-latitude troposphere, the NLTE takes place much lower than in the troposphere under typical temperature conditions. If the NIR-radiation reflection from the surface is ignored, the population of high vibrational states substantially decreases, at least, in some layer of the lower atmosphere. However, inelastic collisions of CO₂ and CO molecules with O atoms produce no considerable influence on the values of populations. The population of vibrational states, the transitions from which form NIR bands, is also almost insensitive to possible large values of the quenching-in-collision rate constants of vibrational states higher than CO₂(00⁰1). However, very large errors in the estimates of the population of vibrational states of the CO₂ molecule (rather than the CO molecule!) can be caused by the uncertainty in the values of the rate constant of exchange between CO² molecules by the energy quantum of the asymmetric stretching vibrational mode. For this intermolecular exchange, we recommend a possible way to restrict the vibrational excitation degree of the molecule that is a collision partner and to maintain simultaneously a sufficiently high accuracy in the population estimate.  相似文献   

Additional radiative cooling of the upper mesosphere and lower thermosphere caused by tidal perturbations in temperature     

V. P. Ogibalov  A. I. Pogoreltsev  I. N. Fedulina  G. M. Shved 《Izvestiya Atmospheric and Oceanic Physics》2006,42(1):84-92

The effect of tidal perturbations in temperature on the rate of cooling the upper mesosphere and lower thermosphere in the CO₂ 15-μm band is revised. It is shown that the effect of solar semidiurnal tide on radiative cooling can be neglected. However, the solar diurnal tide leads to a marked increase in the rate of radiative cooling (up to a relative increase by about 0.1 to 0.2) near the equator at altitudes below 100 km. It is possible that this additional cooling is responsible for the air descent observed in the near-equatorial thermosphere at altitudes above 105 km. Original Russian Text ? V.P. Ogibalov, A.I. Pogoreltsev, I.N. Fedulina, G.M. Shved, 2006, published in Izvestiya AN. Fizika Atmosfery i Okeana, 2006, Vol. 42, No. 1, pp. 92–101.  相似文献   

An Improved Optical Model for the Non-LTE Problem for the CO2 Molecule in the Atmosphere of Mars: Nighttime Populations of Vibrational States and the Rate of Radiative Cooling of the Atmosphere     

Ogibalov  V. P.  Shved  G.M. 《Solar System Research》2003,37(1):20-30

The estimates of the population of excited vibrational states of the CO₂ molecule and of the rate of radiative cooling of the atmosphere in the 15-m CO₂ band are given for the nighttime mesosphere and thermosphere of Mars. For the first time, these estimates are made (1) with allowance for the overlap of lines in the 15-m band; (2) for a wide set of vibrational states of seven isotopes of the CO₂ molecule, which was used earlier in the solution of a similar terrestrial problem; and (3) using the rate constant for quenching of the CO₂(01¹0) state in collisions with oxygen atoms, which has been recently measured for low temperatures by Khvorostovskaya et al. (2002). The main results are as follows. 1. The approximation of isolated lines provides a satisfactory accuracy of determining the radiative cooling rate and overestimates vibrational temperatures of the states of the ₂ mode by no more than 3 K for the ¹²C¹⁶O₂ molecule and by no more than 2 K for low-abundant isotopes of the CO₂ molecule. 2. A reasonably high accuracy of estimating the cooling rate can be achieved by taking into account only fundamental vibrational transitions in ¹²C¹⁶O₂, ¹³C¹⁶O₂, ¹⁶O¹²C¹⁸O, and ¹⁶O¹²C¹⁷O molecules and the hot transitions 2_{2 2} and 3₂ 2₂ in the ¹²C¹⁶O₂ molecule. 3. The vertical profile of the total rate of radiative cooling displays two peaks. The maximum near a height of 130 km is very sensitive to temperature and to the ratio of the mixture for oxygen in the atmosphere.  相似文献   

Increase in the carbon dioxide infrared emissions during solar proton events     

V. P. Ogibalov  S. N. Khvorostovskii  G. M. Shved 《Geomagnetism and Aeronomy》2006,46(2):151-158

Increase in the nighttime high-latitude nonthermal emissions in the mesosphere and lower thermosphere in the 4.3 and 15 μm CO₂ bands during solar proton events has been estimated for the first time. The estimations have been performed for protons with energies not lower than 1 MeV precipitating into the atmosphere. A strong increase in the 4.3 μm emission can be anticipated during the above events; however, a substantial increase in the 15 μm emission is improbable. The 4.3 μm emission can increase only above approximately 80 km regardless of the energy of precipitating protons. The excitation of CO₂ vibrational states, transitions from which generate the 4.3 μm emission, is caused by the vibrational excitation of N₂ molecules due to collisions with secondary electrons, produced during solar proton events, and the following transfer of this excitation to CO₂(00⁰1) molecules during N₂-CO₂ collisions. Original Russian Text ? V.P. Ogibalov, S.N. Khvorostovskii, G.M. Shved, 2006, published in Geomagnetizm i Aeronomiya, 2006, Vol. 46, No. 2, pp. 159–167.  相似文献