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Proceedings Paper

Vertical profile radiation measurements: a spectroscopic tool
Author(s): William L. Smith; Daniel K. Zhou; Allen M. Larar
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Paper Abstract

Airborne profiles of spectral radiances between 3.5 and 15 microns are used to derive profiles of atmospheric temperature and the concentrations of radiatively active absorbing gases. These measurements are intended for the validation of atmospheric radiative transfer physics and associated forward models as well satellite remote sensing techniques and products. Vertical profiles of upwelling spectral radiance are obtained during ascents and descents of the Proteus aircraft carrying the NPOESS Airborne Sounding Test-bed - Interferometer (NAST-I). Opaque region radiance measurements provide the vertical temperature profile while the vertical derivative of radiance with respect to Planck radiance provides the vertical distribution of spectral emissivity. Spectral regions where only a single absorbing gas is active can be used to derive the mixing ratio profile for that gas, assuming the spectroscopy (i.e., line strengths, shapes, and pressure and temperature dependencies) is accurately known for the spectral region used. For the case where the gaseous mixing ratio is either known to be well mixed (e.g., CO2) or is measured in-situ from aircraft or balloon profile observations, the accuracy of the spectroscopic parameters used for radiative transfer calculations can be validated. In this paper, results obtained from vertical profile measurements associated with four different air mass conditions are used to depict the errors associated with radiative transfer calculations within the R-branch of the 15micrometers CO2 band. The airborne spectrometer observation technique illustrated here is proving to be a useful spectroscopic validation tool.

Paper Details

Date Published: 30 January 2002
PDF: 8 pages
Proc. SPIE 4485, Optical Spectroscopic Techniques, Remote Sensing, and Instrumentation for Atmospheric and Space Research IV, (30 January 2002); doi: 10.1117/12.454239
Show Author Affiliations
William L. Smith, NASA Langley Research Ctr. (United States)
Daniel K. Zhou, NASA Langley Research Ctr. (United States)
Allen M. Larar, NASA Langley Research Ctr. (United States)

Published in SPIE Proceedings Vol. 4485:
Optical Spectroscopic Techniques, Remote Sensing, and Instrumentation for Atmospheric and Space Research IV
Allen M. Larar; Martin G. Mlynczak, Editor(s)

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