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Retrieval of XCO2 from simulated Orbiting Carbon Observatory measurements using the fast linearized R-2OS radiative transfer model

Natraj, Vijay and Boesch, Hartmut and Spurr, Robert J. D. and Yung, Yuk L. (2008) Retrieval of XCO2 from simulated Orbiting Carbon Observatory measurements using the fast linearized R-2OS radiative transfer model. Journal of Geophysical Research D, 113 (11). D11212. ISSN 0148-0227. doi:10.1029/2007JD009017. https://resolver.caltech.edu/CaltechAUTHORS:NATjgrd08

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Abstract

In a recent paper, we introduced a novel technique to compute the polarization in a vertically inhomogeneous, scattering-absorbing medium using a two orders of scattering (2OS) radiative transfer (RT) model. The 2OS computation is an order of magnitude faster than a full multiple scattering scalar calculation and can be implemented as an auxiliary code to compute polarization in operational retrieval algorithms. In this paper, we employ the 2OS model for polarization in conjunction with a scalar RT model (Radiant) to simulate backscatter measurements in near infrared (NIR) spectral regions by space-based instruments such as the Orbiting Carbon Observatory (OCO). Computations are performed for six different sites and two seasons, representing a variety of viewing geometries, surface and aerosol types. The aerosol extinction (at 13000 cm^−1) was varied from 0 to 0.3. The radiance errors using the Radiant/2OS (R-2OS) RT model are an order of magnitude (or more) smaller than errors arising from the use of the scalar model alone. In addition, we perform a linear error analysis study to show that the errors in the retrieved column-averaged dry air mole fraction of CO2 (XCO2) using the R-2OS model are much lower than the “measurement” noise and smoothing errors appearing in the inverse model. On the other hand, we show that use of the scalar model alone induces X CO2 errors that could dominate the retrieval error budget.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1029/2007JD009017DOIArticle
ORCID:
AuthorORCID
Natraj, Vijay0000-0003-3154-9429
Boesch, Hartmut0000-0003-3944-9879
Yung, Yuk L.0000-0002-4263-2562
Additional Information:Copyright 2008 by the American Geophysical Union. Received 29 May 2007; revised 23 August 2007; accepted 11 December 2007; published 14 June 2008. The research described in this paper was performed for the Orbiting Carbon Observatory Project at the Jet Propulsion Laboratory, California Institute of Technology, under contracts with NASA. This work was supported in part by NASA grant NAG1-1806. The authors would like to thank Hari Nair for assistance with the forward model and error analysis simulations; Ralph Kahn for discussions on aerosols; Michael Mishchenko, Joop Hovenier and Johan de Haan for providing T matrix and Mie codes; Dave Crisp for assistance with detector optics; Run-Lie Shia and Dan Feldman for helpful comments on the manuscript; and two anonymous reviewers for suggestions to revise the manuscript.
Funders:
Funding AgencyGrant Number
NASANAG1-1806
Subject Keywords:retrieval, OCO, radiative transfer
Issue or Number:11
DOI:10.1029/2007JD009017
Record Number:CaltechAUTHORS:NATjgrd08
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:NATjgrd08
Official Citation:Natraj, V., H. Boesch, R. J. D. Spurr, and Y. L. Yung (2008), Retrieval of XCO2 from simulated Orbiting Carbon Observatory measurements using the fast linearized R-2OS radiative transfer model, J. Geophys. Res., 113, D11212, doi:10.1029/2007JD009017.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:12750
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:22 Dec 2008 20:34
Last Modified:08 Nov 2021 22:32

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