Effects of Particulate Matter on the Radiance of Terrestrial Infrared Radiation: RESULTS

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  • 1 Dept. of Meteorology and Institute of Geophysics and Planetary Physics, University of California, Los Angeles 90024
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Abstract

The effects of particulate matter on the radiance of the emerging terrestrial infrared radiation for six wave-numbers in the wings and centers of the 6.3-µm water vapor and 15-µm carbon dioxide absorption bands have been theoretically evaluated using the mathematical formulation developed by Sekera and Stowe. Atmospheric models based on measured aerosol particle concentration and radiosonde data have been used in the computations, characterizing atmospheric turbidity conditions in low, middle and high latitudes. Empirical formulas by Golubitskiy and Moskalenko were used in the calculation of the molecular absorption parameters, while the scattering and absorption data for the particulates were taken from tables by Deirmendjian.

The changes in radiance of the upward radiation emerging from models of clear atmospheres due to the presence of particulates have been computed for nadir angles 0° ≤ ζ ≤ 70° and found to be rather small, reducing the radiance from a clear atmosphere by less than 1% in most cases. However, certain quantities used in the determination of temperature and humidity vertical profiles from terrestrial radiation measurements by satellite (inversion problems) are subject to larger changes if the effects of particulate matter are disregarded.

Abstract

The effects of particulate matter on the radiance of the emerging terrestrial infrared radiation for six wave-numbers in the wings and centers of the 6.3-µm water vapor and 15-µm carbon dioxide absorption bands have been theoretically evaluated using the mathematical formulation developed by Sekera and Stowe. Atmospheric models based on measured aerosol particle concentration and radiosonde data have been used in the computations, characterizing atmospheric turbidity conditions in low, middle and high latitudes. Empirical formulas by Golubitskiy and Moskalenko were used in the calculation of the molecular absorption parameters, while the scattering and absorption data for the particulates were taken from tables by Deirmendjian.

The changes in radiance of the upward radiation emerging from models of clear atmospheres due to the presence of particulates have been computed for nadir angles 0° ≤ ζ ≤ 70° and found to be rather small, reducing the radiance from a clear atmosphere by less than 1% in most cases. However, certain quantities used in the determination of temperature and humidity vertical profiles from terrestrial radiation measurements by satellite (inversion problems) are subject to larger changes if the effects of particulate matter are disregarded.

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