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Comparison of PARASOL Observations with Polarized Reflectances Simulated Using Different Ice Habit MixturesInsufficient knowledge of the habit distribution and the degree of surface roughness of ice crystals within ice clouds is a source of uncertainty in the forward light scattering and radiative transfer simulations required in downstream applications involving these clouds. The widely used MODerate Resolution Imaging Spectroradiometer (MODIS) Collection 5 ice microphysical model assumes a mixture of various ice crystal shapes with smooth-facets except aggregates of columns for which a moderately rough condition is assumed. When compared with PARASOL (Polarization and Anisotropy of Reflectances for Atmospheric Sciences coupled with Observations from a Lidar) polarized reflection data, simulations of polarized reflectance using smooth particles show a poor fit to the measurements, whereas very rough-faceted particles provide an improved fit to the polarized reflectance. In this study a new microphysical model based on a mixture of 9 different ice crystal habits with severely roughened facets is developed. Simulated polarized reflectance using the new ice habit distribution is calculated using a vector adding-doubling radiative transfer model, and the simulations closely agree with the polarized reflectance observed by PARASOL. The new general habit mixture is also tested using a spherical albedo differences analysis, and surface roughening is found to improve the consistency of multi-angular observations. It is suggested that an ice model incorporating an ensemble of different habits with severely roughened surfaces would potentially be an adequate choice for global ice cloud retrievals.
Document ID
20120012407
Acquisition Source
Goddard Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Cole, Benjamin H.
(Texas A&M Univ. College Station, TX, United States)
Yang, Ping
(Texas A&M Univ. College Station, TX, United States)
Baum, Bryan A.
(Wisconsin Univ. Madison, WI, United States)
Riedi, Jerome
(Universite des Sciences et Techniques de Lille Flandres Artois Villeneuve D'Ascq, France)
Labonnote, Laurent C.
(Universite des Sciences et Techniques de Lille Flandres Artois Villeneuve D'Ascq, France)
Thieuleux, Francois
(Universite des Sciences et Techniques de Lille Flandres Artois Villeneuve D'Ascq, France)
Platnick, Steven
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 26, 2013
Publication Date
January 1, 2012
Subject Category
Meteorology And Climatology
Report/Patent Number
GSFC-JA-01236-2012
Funding Number(s)
CONTRACT_GRANT: NNX10AL55G
CONTRACT_GRANT: NNX11AF40G
CONTRACT_GRANT: NNX11AK37G
Distribution Limits
Public
Copyright
Public Use Permitted.
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