Direct Absorption of Solar Radiation by Atmospheric Water Vapor, Carbon Dioxide and Molecular Oxygen

Abstract

Based mainly on Howard, Burch and Williams' laboratory absorption data for the near infrared H₂O and CO₂, bands, and on the solar absorption data for the red and near infrared O₂ bands, the direct absorption of solar radiation in near infrared atmospheric bands has been estimated. The estimated absorptivities of the H₂O bands in the interval from 0.7 to 2.1 μ are in fair agreement with MeDonald's estimates which are based on Fowle's absorption data. However the absorptivities of the H₂O bands from 0.7 to 6.3 μ are larger than McDonald's values. CO₂ and O₂ absorptions become increasingly important in the upper troposphere and in the stratosphere. Average heating (deg C day⁻¹) was also estimated for London's model atmospheres for clear sky conditions, and compared with the similar estimate made by Roach. For the atmosphere above 300 mb the heating estimated in this paper exceeds that estimated by Roach. Conceivable causes of this discrepancy are pointed out.