Publication Abstracts

Chowdhary 1999

Chowdhary, J., 1999: Multiple Scattering of Polarized Light in Atmosphere-Ocean Systems: Application to Sensitivity Analyses of Aerosol Polarimetry. Ph.D. thesis. Columbia University.

Sunlight scattered by small particles in the atmosphere becomes partially polarized, the degree and state of which are sensitive to the physical and chemical properties of these particles. The high accuracy with which these polarization quantities can be measured causes space-borne polarimetry to be a promising remote sensing tool for retrieving tropospheric aerosols, but it also imposes strong requirements on the accuracy and efficiency of the methods used to numerically study such data. Light reflected by the lower atmospheric boundary may, in addition, become highly polarized, necessitating a careful error analysis of the latter scattering contribution to the remotely sensed signal. Part I of this work focusses, on the former requirements for an atmosphere-ocean system, and discusses an approach for treating scattering of light by water body, ocean surface, and atmosphere together in one method while employing numerically efficient techniques for each of these three components. Benchmark results are provided with an accuracy of 5 decimals for the Stokes vectors of scattering contributions to internal and external fields, and we discuss typical features seen in the bidirectional behaviour of the latter contributions. In Part II, we investigate uncertainties in the reflection properties of the ocean system and the resulting variation in degree of linear polarization observed from space. Three sources of uncertainty are identified: oceanic foam, the ocean surface roughness, and underwater light scattering. The magnitude of the latter two sources are derived from current remote sensing capabilities to retrieve the surface windspeed and oceanic pigment concentration, respectively. Simulations are carried out for the visible and near infrared part of the spectrum and two aerosol models. Our analyses indicate that the use of a priori information on the state of the ocean can provide enough constraints for aerosol polarimetry to be sufficiently accurate for climate research, and they give detailed insight on the optimum viewing geometries required for this purpose. Suggestions are given to constrain uncertainties for the other scattering geometries, and we apply our results to a case-study.

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BibTeX Citation

@phdthesis{ch08500r,
  author={Chowdhary, J.},
  title={Multiple Scattering of Polarized Light in Atmosphere-Ocean Systems: Application to Sensitivity Analyses of Aerosol Polarimetry},
  year={1999},
  school={Columbia University},
  address={New York, N.Y.},
}

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RIS Citation

TY  - THES
ID  - ch08500r
AU  - Chowdhary, J.
PY  - 1999
BT  - Multiple Scattering of Polarized Light in Atmosphere-Ocean Systems: Application to Sensitivity Analyses of Aerosol Polarimetry
PB  - Columbia University
CY  - New York, N.Y.
ER  -

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