A Rapid Calculation Model of Atmospheric NLTE Limb Radiation

Abstract

Abstract:

Aiming at solving low computation speed of present non local thermodynamic equilibrium (NLTE) atmospheric radiative transfer model, band model algorithm with high speed and fine accuracy was applied, and NLTE atmospheric radiative transfer model was established. Firstly, vibrational temperature profile was calculated based on the upper and lower level populations. Secondly, departure coefficient and cross section factor were calculated according to atmospheric kinetic temperature, vibrational temperature and partition function. Finally, hemisphere adding method was proposed to solve NLTE radiative transfer equation in limb geometry. Vibrational temperature and cross section factor profile were calculated and analyzed in 1976 U.S. Atmospheric Mode, and atmospheric NLTE limb radiances in daytime of CO2 in 15 μm band at typical tangent heights were investigated. The rapid calculation model was validated by SHARC based on line-by-line algorithm. The rapid calculation model only consumes a few seconds per time, and with fine spectral resolution(1 cm-1).

Key words: non-local thermodynamic equilibrium, vibrational temperature, departure coefficient, absorption cross section factor, limb radiation

CLC Number:

P351

YANG Chun-Ping, ZENG Dan-Dan, GUO Jing, XIONG Xian-Cheng. A Rapid Calculation Model of Atmospheric NLTE Limb Radiation[J]. Journal of Atmospheric and Environmental Optics, 2014, 9(5): 348-353.

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