TY - JOUR

T1 - An Improved Model of Radiative Transfer for the NLTE Problem in the NIR Bands of CO2 and CO Molecules in the Daytime Atmosphere of Mars. 2. Population of Vibrational States

AU - Ogibalov, V. P.

AU - Shved, G. M.

N1 - Ogibalov, V.P., Shved, G.M. An improved model of radiative transfer for the NLTE problem in the NIR bands of CO2 and CO molecules in the daytime atmosphere of Mars. 2. Population of vibrational states. Sol Syst Res 51, 373–385 (2017). https://doi.org/10.1134/S0038094617050070

PY - 2017

Y1 - 2017

N2 - 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.

AB - 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.

KW - Mars

KW - atmosphere

KW - RADIATION

UR - https://link.springer.com/article/10.1134/S0038094617050070

M3 - Article

VL - 51

SP - 373

EP - 385

JO - Solar System Research

JF - Solar System Research

SN - 0038-0946

IS - 5

ER -