Development of the polarized Monte Carlo three dimensional radiative transfer model I3RC-POL

Houghton, Allison

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https://hdl.handle.net/2142/49638 Copy

Description

Title

Development of the polarized Monte Carlo three dimensional radiative transfer model I3RC-POL

Author(s)

Houghton, Allison

Issue Date

2014-05-30T16:53:36Z

Director of Research (if dissertation) or Advisor (if thesis)

Di Girolamo, Larry

Department of Study

Atmospheric Sciences

Discipline

Atmospheric Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Polarization
• Remote Sensing
• Radiative Transfer
• Monte Carlo

Abstract

To understand and resolve uncertainties regarding climate change, accurate observations must be utilized. Satellite remote sensing provides the best way to obtain global observations, yet the assumptions required to convert measured properties of the radiation field to geophysical information yield accuracy levels outside of the necessary range. By using all electromagnetic properties such as spatial, spectral, angular, and polarization these accuracy levels may increase. The National Research Council recognizes this need and states the future of remote sensing observations lie in the development of multi-angle, multi-wavelength, high resolution, polarized retrievals. To meet this need the Jet Propulsion Laboratory in conjunction with the University of Arizona have developed the Multiangle SpectroPolarimetric Imager (MSPI). In order to accurately interpret the data from MSPI, polarized radiative transfer models must be used and currently only one dimension versions are available. When emphasizing the need for accurate observations, using assumptions that introduce error to retrievals, such as the plane parallel assumption need to be avoided. Therefore analysis of MSPI data must be performed by polarized models that can incorporate complex three dimensional domains. Although the number of three dimensional polarized models have been developed, currently none are accessible to the public. This thesis introduces the development of the Polarized Intercomparison of 3D radiation Codes (I3RC-POL); the first publicly available three dimensional, polarized radiative transfer model. Implementation of this model required the modification of many modules and techniques within the original unpolarized I3RC including the extension of the phase function to a 4x4 phase matrix, the representation of a photon as the polarized Stokes vector, and the selection of scattering angles using the rejection method. Current benchmarking results have found that the I3RC-POL yields results within 1% error for unpolarized intensities compared to the original benchmarked I3RC. Polarized benchmark comparisons have also been performed with the I3RC-POL returning results within 3% error for the intensity component of the Stokes vector. Although initial benchmarking results are promising, some uncertainties must still be resolved in both the unpolarized and polarized results. Once fully benchmarked, the hope is that the open source framework of the I3RC-POL may provide a tool that will be shared and developed further by the remote sensing community.

Graduation Semester

2014-05

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http://hdl.handle.net/2142/49638

Copyright and License Information

Copyright 2014 Allison Houghton

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