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Ground-based photon path measurements from solar absorption spectra of the O_2 A-band

Yang, Z. and Wennberg, P. O. and Cageao, R. P. and Pongetti, T. J. and Toon, G. C. and Sander, S. P. (2005) Ground-based photon path measurements from solar absorption spectra of the O_2 A-band. Journal of Quantitative Spectroscopy and Radiative Transfer, 90 (3-4). pp. 309-321. ISSN 0022-4073. doi:10.1016/j.jqsrt.2004.03.020.

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High-resolution solar absorption spectra obtained from Table Mountain Facility (TMF, 34.38°N, 117.68°W, 2286 m elevation) have been analyzed in the region of the O_2 A-band. The photon paths of direct sunlight in clear sky cases are retrieved from the O_2 absorption lines and compared with ray-tracing calculations based on the solar zenith angle and surface pressure. At a given zenith angle, the ratios of retrieved to geometrically derived photon paths are highly precise (∼0.2%), but they vary as the zenith angle changes. This is because current models of the spectral lineshape in this band do not properly account for the significant absorption that exists far from the centers of saturated lines. For example, use of a Voigt function with Lorentzian far wings results in an error in the retrieved photon path of as much as 5%, highly correlated with solar zenith angle. Adopting a super-Lorentz function reduces, but does not completely eliminate this problem. New lab measurements of the lineshape are required to make further progress.

Item Type:Article
Related URLs:
URLURL TypeDescription
Wennberg, P. O.0000-0002-6126-3854
Pongetti, T. J.0000-0001-9465-0853
Toon, G. C.0000-0003-4174-7541
Sander, S. P.0000-0003-1424-3620
Alternate Title:Ground-based photon path measurements from solar absorption spectra of the O2 A-band
Additional Information:© 2004 Elsevier Ltd. Received 6 October 2003; accepted 13 March 2004. We thank Linda Brown, Camy-Peyret and David Crisp for many helpful discussions, Rebecca Washenfelder for providing comparison spectra. Part of this work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Paul Wennberg, Geoff Toon, and Zhonghua Yang acknowledge support from NASA’s ACMAP and Terrestrial Ecology Programs (NAG5-11739; NAG12247). Stan Sander, Rich Cageao, and Tom Pongetti acknowledge support from the NASA’s Upper Atmosphere Research Program.
Funding AgencyGrant Number
Subject Keywords:O2 A-band; Photon path; Solar absorption spectra
Issue or Number:3-4
Record Number:CaltechAUTHORS:20140703-101456060
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Official Citation:Z. Yang, P.O. Wennberg, R.P. Cageao, T.J. Pongetti, G.C. Toon, S.P. Sander, Ground-based photon path measurements from solar absorption spectra of the O2 A-band, Journal of Quantitative Spectroscopy and Radiative Transfer, Volume 90, Issues 3–4, 1 February 2005, Pages 309-321, ISSN 0022-4073, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:46805
Deposited By: Ruth Sustaita
Deposited On:03 Jul 2014 17:37
Last Modified:10 Nov 2021 17:29

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