Index Catalog // ScholarsArchive@OSU

Aircraft measurements of high average charges on cloud drops in layer clouds

Creator:: Beard, Kenneth V., Ochs, Harry T., III, and Twohy, Cynthia
Abstract:: The first reliable aircraft measurements of characteristic cloud drop charges were obtained by utilizing a counterflow virtual impactor to substantially increase charge sensitivity and eliminate spurious contact charging that contaminated previous aircraft measurements. We find average drop charges more than an order of magnitude larger than expected from mountain surface...
Resource Type:: Article
Full Text:: cloud drops in layer clouds Kenneth V. Beard,1,2 Harry T. Ochs III,1,2 and Cynthia H. Twohy3 Received

Nitrogenated organic aerosols as cloud condensation nuclei

Creator:: Twohy, Cynthia, Anderson, J. R., and Crozier, P. A.
Abstract:: One important role of anthropogenic aerosol particles is their influence on climate by acting as cloud condensation nuclei. However, these particles are diverse in composition and mixing state, and our knowledge of which particle types act as cloud condensation nuclei is incomplete. Here we present direct measurements of individual organic...
Resource Type:: Article
Full Text:: detectable with EELS). Figure 2c shows the derived elemental profiles. Relative atomic concentration ratios

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:: Bilt, Netherlands MATTHEW J. MCGILL NASA Goddard Space Flight Center, Greenbelt, Maryland CYNTHIA

Improvements to an Empirical Parameterization of Heterogeneous Ice Nucleation and Its Comparison with Observations

Creator:: Phillips, Vaughan T. J., Demott, Paul J., Andronache, Constantin, Pratt, Kerri A., Prather, Kimberly A., Subramanian, R., and Twohy, Cynthia
Abstract:: A framework for an empirical parameterization (EP) of heterogeneous nucleation of ice crystals by multiple species of aerosol material in clouds was proposed in a 2008 paper by the authors. The present paper reports improvements to specification of a few of its empirical parameters. These include temperatures for onset of...
Resource Type:: Article
Full Text:: . DEMOTT,1 CONSTANTIN ANDRONACHE,# KERRI A. PRATT,@,11 KIMBERLY A. PRATHER,@ R. SUBRAMANIAN,& AND CYNTHIA

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

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:: . FIELD,1 MATT BAILEY,# DAVE ROGERS,* JEFFREY STITH,* CYNTHIA TWOHY,@ ZHIEN WANG,& AND SAMUEL HAIMOV

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

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:: . DeMott,1 Cynthia Twohy,2 Michael R. Poellot,3 Sonia M. Kreidenweis,1 David C. Rogers,5 Sarah D. Brooks

Observation of playa salts as nuclei in orographic wave clouds

Creator:: Pratt, Kerri A., Twohy, Cynthia, Murphy, Shane M., Moffet, Ryan C., Heymsfield, Andrew J., Gaston, Cassandra J., DeMott, Paul J., Field, Paul R., Henn, Tobias R., Rogers, David C., Gilles, Mary K., Seinfeld, John H., and Prather, Kimberly A.
Abstract:: During the Ice in Clouds Experiment‐Layer Clouds (ICE‐L), dry lakebed, or playa, salts from the Great Basin region of the United States were observed as cloud nuclei in orographic wave clouds over Wyoming. Using a counterflow virtual impactor in series with a single‐particle mass spectrometer, sodium‐potassium‐magnesium‐calcium‐chloride salts were identified as...
Resource Type:: Article
Full Text:: orographic wave clouds Kerri A. Pratt,1,2 Cynthia H. Twohy,3 Shane M. Murphy,4,5 Ryan C. Moffet,6 Andrew J

Saharan dust particles nucleate droplets in eastern Atlantic clouds

Creator:: Twohy, Cynthia, Kreidenweis, Sonia M., Eidhammer, Trude, Browell, Edward V., Heymsfield, Andrew J., Bansemer, Aaron R., Anderson, Bruce E., Chen, Gao, Ismail, Syed, DeMott, Paul J., and Van Den Heever, Susan C.
Abstract:: Many soil-derived particles dominated by insoluble material, including Saharan dusts, are known to act as ice nuclei. If, however, dust particles can compete with other atmospheric particle types to form liquid cloud droplets, they have a greater potential to change climate through indirect effects on cloud radiative properties and to...
Resource Type:: Article
Full Text:: Atlantic clouds Saharan dust particles nucleate droplets in eastern Atlantic clouds Cynthia H. Twohy,1

ScholarsArchive@OSU

Aircraft measurements of high average charges on cloud drops in layer clouds

Nitrogenated organic aerosols as cloud condensation nuclei

Effective Radius of Ice Cloud Particle Populations Derived from Aircraft Probes

Improvements to an Empirical Parameterization of Heterogeneous Ice Nucleation and Its Comparison with Observations

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

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

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

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

Observation of playa salts as nuclei in orographic wave clouds

Saharan dust particles nucleate droplets in eastern Atlantic clouds

Limit your search

Academic Affiliation

Creator

Date

Decade

Language

Peer Reviewed

Resource Type

Rights Statement

Search Constraints

Search Results

Limit your search