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Sensitivity of Multiangle, Multispectral Polarimetric Remote Sensing Over Open Oceans to Water-Leaving Radiance: Analyses of RSP Data Acquired During the MILAGRO CampaignFor remote sensing of aerosol over the ocean, there is a contribution from light scattered underwater. The brightness and spectrum of this light depends on the biomass content of the ocean, such that variations in the color of the ocean can be observed even from space. Rayleigh scattering by pure sea water, and Rayleigh-Gans type scattering by plankton, causes this light to be polarized with a distinctive angular distribution. To study the contribution of this underwater light polarization to multiangle, multispectral observations of polarized reflectance over ocean, we previously developed a hydrosol model for use in underwater light scattering computations that produces realistic variations of the ocean color and the underwater light polarization signature of pure sea water. In this work we review this hydrosol model, include a correction for the spectrum of the particulate scattering coefficient and backscattering efficiency, and discuss its sensitivity to variations in colored dissolved organic matter (CDOM) and in the scattering function of marine particulates. We then apply this model to measurements of total and polarized reflectance that were acquired over open ocean during the MILAGRO field campaign by the airborne Research Scanning Polarimeter (RSP). Analyses show that our hydrosol model faithfully reproduces the water-leaving contributions to RSP reflectance, and that the sensitivity of these contributions to Chlorophyll a concentration [Chl] in the ocean varies with the azimuth, height, and wavelength of observations. We also show that the impact of variations in CDOM on the polarized reflectance observed by the RSP at low altitude is comparable to or much less than the standard error of this reflectance whereas their effects in total reflectance may be substantial (i.e. up to >30%). Finally, we extend our study of polarized reflectance variations with [Chl] and CDOM to include results for simulated spaceborne observations.
Document ID
20120008932
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Chowdhary, Jacek
(Columbia Univ. New York, NY, United States)
Cairns, Brian
(Columbia Univ. New York, NY, United States)
Waquet, Fabien
(Universite des Sciences et Techniques de Lille Flandres Artois Villeneuve D'Ascq, France)
Knobelspiesse, Kirk
(Columbia Univ. New York, NY, United States)
Ottaviani, Matteo
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Redemann, Jens
(NASA Ames Research Center Moffett Field, CA, United States)
Travis, Larry
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Mishchenko, Michael
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 25, 2013
Publication Date
March 15, 2012
Publication Information
Publication: Remote Sensing of Environment
Volume: 118
Subject Category
Earth Resources And Remote Sensing
Report/Patent Number
GSFC.JA.5998.2012
Distribution Limits
Public
Copyright
Other

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