Formation of cirrus clouds depends on the availability of ice nuclei to begin condensation of atmospheric water vapor. Although it is known that only a small fraction of atmospheric aerosols are efficient ice nuclei, the critical ingredients that make those aerosols so effective have not been established. We have determined...
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the Dominant Sources and Mechanisms of Cirrus Cloud
Formation
Daniel J. Cziczo,* Karl D. Froyd
Formation of cirrus clouds depends on the availability of ice nuclei to begin condensation of atmospheric water vapor. Although it is known that only a small fraction of atmospheric aerosols are efficient ice nuclei, the critical ingredients that make those aerosols so effective have not been established. We have determined...
Full Text:
Mechanisms of Cirrus Cloud Formation
Daniel J. Cziczo,1* Karl D. Froyd,2,3 Corinna Hoose,4 Eric J. Jensen,5
Formation of cirrus clouds depends on the availability of ice nuclei to begin condensation of atmospheric water vapor. Although it is known that only a small fraction of atmospheric aerosols are efficient ice nuclei, the critical ingredients that make those aerosols so effective have not been established. We have determined...
Airborne measurements over the northern Pacific are
evaluated to characterize properties of black carbon (BC) in
cirrus crystal residuals and background aerosols in the upper
troposphere. Although the mass and number concentrations
of BC were 7–25 times lower in crystal residuals than in
particles outside of cloud, twice as many...
Knowledge of cloud and precipitation formation processes remains
incomplete, yet global precipitation is predominantly produced by
clouds containing the ice phase. Ice first forms in clouds warmer
than −36 °C on particles termed ice nuclei. We combine observations
from field studies over a 14-year period, from a variety of
locations...
In situ airborne sampling of refractory black carbon (rBC) particles and Ice Nuclei (IN) was conducted in and near an extratropical cyclonic storm in the western Pacific Ocean during the Pacific Dust Experiment, PACDEX, in the spring of 2007. Airmass origins were from Eastern Asia. Clouds associated primarily with the...
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...
The initiation of ice in an isolated orographic wave cloud was compared with expectations based on ice nucleating aerosol concentrations and with predictions from new ice nucleation parameterizations applied in a cloud parcel model. Measurements of ice crystal number concentrations were found to be in good agreement both with measured...
A counterflow virtual impactor was used to collect residual particles larger than about 0.1 μm diameter from anvil cirrus clouds generated over Florida in the southern United States. A wide variety of particle types were found. About one-third of the nuclei were salts, with varying amounts of crustal material, industrial...