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Derivation of Physical and Optical Properties of Midlatitude Cirrus Ice Crystals for a Size-Resolved Cloud Microphysics ModelSingle-crystal images collected in mid-latitude cirrus are analyzed to provide internally consistent ice physical and optical properties for a size-resolved cloud microphysics model, including single-particle mass, projected area, fall speed, capacitance, single-scattering albedo, and asymmetry parameter. Using measurements gathered during two flights through a widespread synoptic cirrus shield, bullet rosettes are found to be the dominant identifiable habit among ice crystals with maximum dimension (Dmax) greater than 100μm. Properties are therefore first derived for bullet rosettes based on measurements of arm lengths and widths, then for aggregates of bullet rosettes and for unclassified (irregular) crystals. Derived bullet rosette masses are substantially greater than reported in existing literature, whereas measured projected areas are similar or lesser, resulting in factors of 1.5-2 greater fall speeds, and, in the limit of large Dmax, near-infrared single-scattering albedo and asymmetry parameter (g) greater by approx. 0.2 and 0.05, respectively. A model that includes commonly imaged side plane growth on bullet rosettes exhibits relatively little difference in microphysical and optical properties aside from approx. 0:05 increase in mid-visible g primarily attributable to plate aspect ratio. In parcel simulations, ice size distribution, and g are sensitive to assumed ice properties.
Document ID
20160007925
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Fridlind, Ann M.
(NASA Goddard Inst. for Space Studies New York, NY United States)
Atlas, Rachel
(Chicago Univ. Chicago, IL, United States)
Van Diedenhoven, Bastiaan
(Columbia Univ. New York, NY, United States)
Um, Junshik
(Illinois Univ. Urbana-Champaign, IL, United States)
McFarquhar, Greg M.
(Illinois Univ. Urbana-Champaign, IL, United States)
Ackerman, Andrew S.
(NASA Goddard Inst. for Space Studies New York, NY United States)
Moyer, Elisabeth J.
(Chicago Univ. Chicago, IL, United States)
Lawson, R. Paul
(Spec, Inc. Boulder, CO, United States)
Date Acquired
June 27, 2016
Publication Date
June 10, 2016
Publication Information
Publication: Atmospheric Chemistry and Physics
Publisher: Copernicus Publications
Volume: 16
Issue: 11
e-ISSN: 1680-7324
Subject Category
Meteorology And Climatology
Report/Patent Number
GSFC-E-DAA-TN33049
Funding Number(s)
CONTRACT_GRANT: DE-AC02-05CH11231
CONTRACT_GRANT: NNX14AB99A
Distribution Limits
Public
Copyright
Other
Keywords
asymmetry
optical properties
single crystals
crystals
temperate regions
albedo
ice

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