TITLE:
  Evidence of non-LTE effects on the mesospheric water vapor observed
  by spectrally resolved transitional-emissions from CIRRIS-1A

AUTHORS:
  Zhou, D. K., M. G. Mlynczak, M. Lopez-Puertas, and G. Zaragoza

REFERENCE:
  Geophy. Res. Lett., 26, 67-70, 1999 

ABSTRACT:
Evidence of non-LTE effects in mesospheric water vapor as determined by 
infrared spectral emission measurements taken from the space shuttle is 
reported. A cryogenic Michelson interferometer in the CIRRIS-1A shuttle 
payload yielded high quality atmospheric infrared spectra. These measurements 
demonstrate the enhanced daytime emissions of H2O (020-010) which are the 
result of non-LTE processes and in agreement with non-LTE models. The 
radiance ratios of H2O (010-000) and (020-010) Q(1) transitions during 
daytime are compared with non-LTE model calculations to assess the 
vibration-to-vibration exchange rate between H2O and O2 in the mesosphere. 
An exchange rate of 1.2E-12 cm3/s is derived.