TITLE:
  Non-Local-Thermodynamic-Equilibrium populations of the first 
  vibrational excited state of CO in the middle atmosphere 

AUTHORS:
  Lopez-Puertas, M., M. A. Lopez-Valverde, D. P. Edwards and F. W. Taylor 

REFERENCE:
  J. Geophys. Res., 89, pp.8933-8947, 1993

ABSTRACT:

A non-LTE radiative transfer model for the population of the CO(1)
vibrational state in the middle atmosphere is presented. Radiative transfer
is treated by using the Curtis matrix method. The transmittances needed for
the Curtis matrix have been computed by using the GENLN2 line-by-line
radiance/transmittance code. A study of the radiative and collisional
processes and atmospheric parameters that affect the population of CO(1)
populations has been performed. We find that the tropospheric kinetic
temperature and CO abundance profiles play an important role through
radiative coupling in the population of mesospheric CO(1) at night-time.
During the day, the solar flux and the mesospheric CO abundance are the main
factors determining the CO vibrational temperature in the mesosphere.
Non-thermal collisions with the atmospheric N2(1) are also shown to be
important for the daytime population of CO(1) in that region. The
consequences of these results for the retrieval of CO abundances from the
remote sensing of radiance at 4.7-mu are discussed.