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The 2 stream-exact single scattering (2S-ESS) radiative transfer model

Natraj, V. and Spurr, R. and Gao, A. and Le, T. and Zeng, Z. C. and Fan, S. and Yung, Y. L. (2023) The 2 stream-exact single scattering (2S-ESS) radiative transfer model. Journal of Quantitative Spectroscopy and Radiative Transfer, 295 . Art. No. 108416. ISSN 0022-4073. doi:10.1016/j.jqsrt.2022.108416.

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The plane-parallel two-stream approximation is a popular radiative transfer approach for the calculation of fluxes and heating rates. However, it is typically not accurate enough for remote sensing applications involving the analysis of hyperspectral radiances. We present the 2 stream-exact single scattering (2S-ESS) radiative transfer model, which performs an exact calculation of single scattering in a spherically curved medium using an accurate treatment of the phase function and curved ray-tracing of the solar and line-of-sight paths, while approximating multiple scattering with the plane-parallel two-stream approach. The 2S-ESS model has three important features. First, it can be deployed for calculations in vertically inhomogeneous atmospheres. Second, the sphericity capability makes it applicable to large solar and/or viewing zenith angle scenarios such as those encountered close to sunrise or sunset. Third, it is fully linearized: in addition to generating radiances, the model can also compute Jacobians analytically with respect to any atmospheric or surface property (e.g., trace gases, aerosols and surface reflectance). These features of the model are especially useful for remote sensing retrieval applications. We examine the accuracy of this model for homogeneous slab and inhomogeneous multi-layer scenarios. The results show that this methodology introduces less than a few percent error in most situations, with the exception of heavy aerosol or cloud loading events, while providing three orders of magnitude improvement in computational efficiency. The code is publicly available along with documentation and test cases to assist the user.

Item Type:Article
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URLURL TypeDescription
Natraj, V.0000-0003-3154-9429
Spurr, R.0000-0002-6772-5992
Yung, Y. L.0000-0002-4263-2562
Additional Information:A portion of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). VN acknowledges support from the Tropospheric Ozone and its Precursors from Earth System Sounding (TROPESS) project. The authors gratefully acknowledge the insightful and constructive comments from the two anonymous reviewers, which improved the clarity and quality of the manuscript.
Group:Division of Geological and Planetary Sciences
Funding AgencyGrant Number
Record Number:CaltechAUTHORS:20230103-817548100.15
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:118620
Deposited By: Research Services Depository
Deposited On:27 Jan 2023 14:52
Last Modified:27 Jan 2023 18:11

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