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Monochromatic calculations of atmospheric radiative transfer due to molecular line absorptionSensitivity studies related to the effects of line cutoff, spectral resolution, and temperature and pressure interpolations in radiative transfer have been performed so that a data set of absorption coefficients for water vapor, CO2, and O3 may be created efficiently. Results show that computations of absorption coefficients are affected only slightly by cutting a line off at a wave number 190 times the Lorentz half width from the center, or equivalently, cutting off 0.33 percent of the line intensity from the wings. To achieve a relative cooling rate error smaller than 2 percent, it is sufficient to precompute the absorption coefficient at three temperatures (210, 250, and 290 K) and 19 pressures with Delta (log 10 p) = 0.2. The absorption coefficient at other conditions can be interpolated linearly with pressure and exponentially with a quadratic in temperature. For the spectral resolution the absorption coefficients can be adequately computed at 0.01, 0.002, 0.005, and 0.025/cm intervals in the thermal water vapor, the CO2 and O3 bands, and the solar water vapor bands, respectively, which limits the error to only a few percent in the cooling and heating rates. Using the precomputed absorption coefficients, repeated monochromatic calculations of atmospheric heating/cooling rates for radiation model developments and for comparison with less detailed calculations are no longer difficult.
Document ID
19860049467
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Chou, M.-D.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Kouvaris, L.
(Applied Research Corp. Landover, MD, United States)
Date Acquired
August 12, 2013
Publication Date
March 20, 1986
Publication Information
Publication: Journal of Geophysical Research
Volume: 91
ISSN: 0148-0227
Subject Category
Geophysics
Accession Number
86A34205
Distribution Limits
Public
Copyright
Other

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