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...
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...
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...
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...
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...
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...
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...
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...
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...
The ambient temperatures and humidities required for contrail formation
and persistence are determined from in situ measurements during the
Subsonic Aircraft: Contrail and Cloud Effects Special Study (SUCCESS) experiment.
Ambient temperatures and water vapor concentrations were measured
with the meteorological measurement system, a laser hygrometer, and a cryogenic
hygrometer (all...