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Title: Derivation of physical and optical properties of mid-latitude cirrus ice crystals for a size-resolved cloud microphysics model

Abstract

Single-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 ( D max) greater than 100 µm. 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 D max, near-infrared single-scattering albedo and asymmetry parameter ( g) greater by ~0.2 and 0.05, respectively. Furthermore, a model that includes commonly imaged side plane growth on bullet rosettes exhibits relatively little difference in microphysical and optical properties aside from ~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.

Authors:
 [1];  [2];  [3];  [4];  [4];  [1];  [2];  [5]
  1. NASA Goddard Inst. for Space Studies, New York, NY (United States)
  2. Univ. of Chicago, Chicago, IL (United States)
  3. NASA Goddard Inst. for Space Studies, New York, NY (United States); Columbia Univ., New York, NY (United States)
  4. Univ. of Illinois, Urbana-Champaign, IL (United States)
  5. Spec Inc., Boulder, CO (United States)
Publication Date:
Research Org.:
NASA Goddard Inst. for Space Studies (GISS), New York, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
OSTI Identifier:
1256532
Grant/Contract Number:
SC0006988; SC0008500; SC001406; AC02-05CH11231; SC0014065
Resource Type:
Journal Article: Published Article
Journal Name:
Atmospheric Chemistry and Physics (Online)
Additional Journal Information:
Journal Name: Atmospheric Chemistry and Physics (Online); Journal Volume: 16; Journal Issue: 11; Journal ID: ISSN 1680-7324
Publisher:
European Geosciences Union
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; single-scattering properties; general hydrodynamic theory; large-eddy simulations; in-situ observations; radiative properties; part i; climate models; water-content; fall speeds; terminal velocities

Citation Formats

Fridlind, Ann M., Atlas, Rachel, van Diedenhoven, Bastiaan, Um, Junshik, McFarquhar, Greg M., Ackerman, Andrew S., Moyer, Elisabeth J., and Lawson, R. Paul. Derivation of physical and optical properties of mid-latitude cirrus ice crystals for a size-resolved cloud microphysics model. United States: N. p., 2016. Web. doi:10.5194/acp-16-7251-2016.
Fridlind, Ann M., Atlas, Rachel, van Diedenhoven, Bastiaan, Um, Junshik, McFarquhar, Greg M., Ackerman, Andrew S., Moyer, Elisabeth J., & Lawson, R. Paul. Derivation of physical and optical properties of mid-latitude cirrus ice crystals for a size-resolved cloud microphysics model. United States. doi:10.5194/acp-16-7251-2016.
Fridlind, Ann M., Atlas, Rachel, van Diedenhoven, Bastiaan, Um, Junshik, McFarquhar, Greg M., Ackerman, Andrew S., Moyer, Elisabeth J., and Lawson, R. Paul. 2016. "Derivation of physical and optical properties of mid-latitude cirrus ice crystals for a size-resolved cloud microphysics model". United States. doi:10.5194/acp-16-7251-2016.
@article{osti_1256532,
title = {Derivation of physical and optical properties of mid-latitude cirrus ice crystals for a size-resolved cloud microphysics model},
author = {Fridlind, Ann M. and Atlas, Rachel and van Diedenhoven, Bastiaan and Um, Junshik and McFarquhar, Greg M. and Ackerman, Andrew S. and Moyer, Elisabeth J. and Lawson, R. Paul},
abstractNote = {Single-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 100 µm. 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 ~0.2 and 0.05, respectively. Furthermore, a model that includes commonly imaged side plane growth on bullet rosettes exhibits relatively little difference in microphysical and optical properties aside from ~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.},
doi = {10.5194/acp-16-7251-2016},
journal = {Atmospheric Chemistry and Physics (Online)},
number = 11,
volume = 16,
place = {United States},
year = 2016,
month = 6
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.5194/acp-16-7251-2016

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  • Single-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 ( D max) greater than 100 µm. 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 bulletmore » 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 D max, near-infrared single-scattering albedo and asymmetry parameter ( g) greater by ~0.2 and 0.05, respectively. Furthermore, a model that includes commonly imaged side plane growth on bullet rosettes exhibits relatively little difference in microphysical and optical properties aside from ~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.« less
  • The single-layer mixed-phase clouds observed during the Atmospheric Radiation Measurement (ARM) program’s Mixed-Phase Arctic Cloud Experiment (MPACE) are simulated with a 3-dimensional cloud-resolving model the System for Atmospheric Modeling (SAM) coupled with an explicit bin microphysics scheme and a radar-lidar simulator. Two possible ice enhancement mechanisms – activation of droplet evaporation residues by condensation-followed-by-freezing and droplet freezing by contact freezing inside-out, are scrutinized by extensive comparisons with aircraft and radar and lidar measurements. The locations of ice initiation associated with each mechanism and the role of ice nuclei (IN) in the evolution of mixed-phase clouds are mainly addressed. Simulations withmore » either mechanism agree well with the in-situ and remote sensing measurements on ice microphysical properties but liquid water content is slightly underpredicted. These two mechanisms give very similar cloud microphysical, macrophysical, dynamical, and radiative properties, although the ice nucleation properties (rate, frequency and location) are completely different. Ice nucleation from activation of evaporation nuclei is most efficient near cloud top areas concentrated on the edges of updrafts, while ice initiation from the drop freezing process has no significant location preference (occurs anywhere that droplet evaporation is significant). Both enhanced nucleation mechanisms contribute dramatically to ice formation with ice particle concentration of 10-15 times higher relative to the simulation without either of them. The contribution of ice nuclei (IN) recycling from ice particle evaporation to IN and ice particle concentration is found to be very significant in this case. Cloud can be very sensitive to IN initially and form a nonquilibrium transition condition, but become much less sensitive as cloud evolves to a steady mixed-phase condition. The parameterization of Meyers et al. [1992] with the observed MPACE IN concentration is able to predict the observed mixed-phase clouds reasonably well. This validation may facilitate the application of this parameterization in the cloud and climate models to simulate Arctic clouds.« less
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