Index Catalog // ScholarsArchive@OSU

Refinements to Ice Particle Mass Dimensional and Terminal Velocity Relationships for Ice Clouds. Part I: Temperature Dependence

Creator:: Heymsfield, Andrew J., Bansemer, Aaron, and Twohy, Cynthia
Abstract:: This two-part study attempts to find appropriate mass dimension and terminal velocity relationships that, when considered together with particle size distributions (PSD), agree with coincident measurements of ice water content (IWC), and with variables related to higher moments such as the mean mass-weighted fall speed. Reliable relationships are required for...
Resource Type:: Article
Full Text:: Velocity Relationships for Ice Clouds. Part I: Temperature Dependence ANDREW J. HEYMSFIELD AND AARON

Upper-tropospheric relative humidity observation and implications for cirrus ice nucleation

Creator:: Heymsfield, Andrew J., Miloshevich, Larry M., Twohy, Cynthia, Sachse, Glen, and Oltmans, Samuel
Abstract:: Relative humidity (RH) measurements acquired in orographic wave cloud and cirrus environments are used to investigate the temperature‐dependent RH required to nucleate ice crystals in the upper troposphere, RHnuc(T). High ice‐supersaturations in clear air—conducive to the maintenance of aircraft contrails yet below RHnuc and therefore insufficient for cirrus formation—are not...
Resource Type:: Article
Full Text:: Andrew J. Heymsfield, Larry M. Miloshevich, and Cynthia Twohy National Center for Atmospheric Research

Measurements of wave-cloud microphysical properties with two new aicraft probes

Creator:: Gerber, H., Twohy, Cynthia, Gandrud, Bruce W., Heymsfield, Andrew J., McFarquhar, Greg M., DeMott, Paul J., and Rogers, David C.
Abstract:: Measurements of ice water content (IWC) and mean ice-crystal size and concentration made by two in-situ probes, C, VI and PVM, were compared on the DC-8 aircraft during SUCCESS flights in orographic ice clouds. The comparison of 1WC in these wave clouds, that formed at temperatures of about -38 °C...
Resource Type:: Article
Full Text:: Gerber Scientific Inc., 1643 Bentana Way, Reston, VA 20190 Cynthia H. Twohy, Bruce Gandrud, Andrew J

Effective Radius of Ice Cloud Particle Populations Derived from Aircraft Probes

Creator:: Heymsfield, Andrew J., Schmitt, Carl, Bansemer, Aaron, van Zadelhoff, Gerd-Jan, McGill, Matthew J., Twohy, Cynthia, and Baumgardner, Darrel
Abstract:: The effective radius (r[subscript]e) is a crucial variable in representing the radiative properties of cloud layers in general circulation models. This parameter is proportional to the condensed water content (CWC) divided by the extinction (σ). For ice cloud layers, parameterizations for r[subscript]e have been developed from aircraft in situ measurements...
Resource Type:: Article
Full Text:: Aircraft Probes ANDREW J. HEYMSFIELD, CARL SCHMITT, AND AARON BANSEMER National Center for Atmospheric

Examinations of ice formation processes in Florida cumuli using ice measurements of anvil ice crystal particle residues

Creator:: Prenni, Anthony J., DeMott, Paul J., Twohy, Cynthia, Poellot, Michael R., Kreidenweis, Sonia M., Rogers, David C., Brooks, Sarah D., Richardson, Matthew S., and Heymsfield, Andrew J.
Abstract:: A continuous flow diffusion chamber (CFDC) was used to measure ice formation by cloud particle residuals during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment. These measurements were directed toward determining the relative contributions of homogeneous nucleation, heterogeneous nucleation, and secondary ice formation processes to...
Resource Type:: Article
Full Text:: ,1,4 Mathews S. Richardson,1 and Andrew J. Heymsfield5 Received 23 May 2006; revised 9 January 2007

Ice in Clouds Experiment—Layer Clouds. Part I: Ice Growth Rates Derived from Lenticular Wave Cloud Penetrations

Creator:: Heymsfield, Andrew J., Field, Paul R., Bailey, Matt, Rogers, Dave, Stith, Jeffrey, Twohy, Cynthia, Wang, Zhien, and Haimov, Samuel
Abstract:: Lenticular wave clouds are used as a natural laboratory to estimate the linear and mass growth rates of ice particles at temperatures from -20° to -32°C and to characterize the apparent rate of ice nucleation at water saturation at a nearly constant temperature. Data are acquired from 139 liquid cloud...
Resource Type:: Article
Full Text:: I: Ice Growth Rates Derived from Lenticular Wave Cloud Penetrations ANDREW J. HEYMSFIELD,* PAUL R

Evidence of nitric acid uptake in warm cirrus anvil clouds during the NASA TC4 campaign

Creator:: Scheuer, Eric, Dibb, Jack E., Twohy, Cynthia, Rogers, David C., Heymsfield, Andrew J., and Bansemer, Aaron
Abstract:: Uptake ofHNO₃ onto cirrus ice may play an important role in tropospheric NOx cycling. Discrepancies between modeled and in situ measurements of gas‐phase HNO₃ in the troposphere suggest that redistribution and removal mechanisms by cirrus ice have been poorly constrained. Limited in situ measurements have provided somewhat differing results and...
Resource Type:: Article
Full Text:: Cynthia Twohy,2 David C. Rogers,3 Andrew J. Heymsfield,4 and Aaron Bansemer4 Received 24 June 2009

The role of heterogeneous freezing nucleation in upper troposphereic clouds : inferences from SUCCESS

Creator:: DeMott, Paul J., Rogers, David C., Kreidenweis, Sonia M., Chen, Yalei, Twohy, Cynthia, Heymsfield, Andrew J., Chan, K. Roland, and Baumgardner, Darrel
Abstract:: A temperature spectrum if heterogeneous freezing nuclei concentrations in continental air in the upper troposphere was determined based on airborne measurements. Numerical model simulations incorporating ice formation by heterogeneous and homogeneous freezing of deliquesced soluble aerosol particles were performed to investigate the effect of the heterogeneous freezing nuclei were predicted...
Resource Type:: Article
Full Text:: Andrew J. Heymsfield National Center for Atmospheric Research, Boulder, CO K. Roland Chan NASA Ames

Relationships of Biomass-Burning Aerosols to Ice in Orographic Wave Clouds

Creator:: Twohy, Cynthia, DeMott, Paul J., Pratt, Kerri A., Subramanian, R., Kok, Gregory L., Murphy, Shane M., Lersch, Traci, Heymsfield, Andrew J., Wang, Zhien, Prather, Kim A., and Seinfeld, John H.
Abstract:: Ice concentrations in orographic wave clouds at temperatures between −24° and −29°C were shown to be related to aerosol characteristics in nearby clear air during five research flights over the Rocky Mountains. When clouds with influence from colder temperatures were excluded from the dataset, mean ice nuclei and cloud ice...
Resource Type:: Article
Full Text:: ,@ GREGORY L. KOK,@ SHANE M. MURPHY,& TRACI LERSCH,** ANDREW J. HEYMSFIELD,11 ZHIEN WANG,## KIM A. PRATHER

In Situ Chemical Characterization of Aged Biomass-Burning Aerosols Impacting Cold Wave Clouds

Creator:: Pratt, Kerri A., Heymsfield, Andrew J., Twohy, Cynthia, Murphy, Shane M., DeMott, Paul J., Hudson, James G., Subramanian, R., Wang, Zhien, Seinfeld, John H., and Prather, Kimberly A.
Abstract:: During the Ice in Clouds Experiment–Layer Clouds (ICE-L), aged biomass-burning particles were identified within two orographic wave cloud regions over Wyoming using single-particle mass spectrometry and electron microscopy. Using a suite of instrumentation, particle chemistry was characterized in tandem with cloud microphysics. The aged biomass-burning particles comprised ~30%–40% by number...
Resource Type:: Article
Full Text:: Biomass-Burning Aerosols Impacting Cold Wave Clouds KERRI A. PRATT,a,b ANDREW J. HEYMSFIELD,c CYNTHIA H

ScholarsArchive@OSU

Refinements to Ice Particle Mass Dimensional and Terminal Velocity Relationships for Ice Clouds. Part I: Temperature Dependence

Upper-tropospheric relative humidity observation and implications for cirrus ice nucleation

Measurements of wave-cloud microphysical properties with two new aicraft probes

Effective Radius of Ice Cloud Particle Populations Derived from Aircraft Probes

Examinations of ice formation processes in Florida cumuli using ice measurements of anvil ice crystal particle residues

Ice in Clouds Experiment—Layer Clouds. Part I: Ice Growth Rates Derived from Lenticular Wave Cloud Penetrations

Evidence of nitric acid uptake in warm cirrus anvil clouds during the NASA TC4 campaign

The role of heterogeneous freezing nucleation in upper troposphereic clouds : inferences from SUCCESS

Relationships of Biomass-Burning Aerosols to Ice in Orographic Wave Clouds

In Situ Chemical Characterization of Aged Biomass-Burning Aerosols Impacting Cold Wave Clouds

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