HR: 15:00h
AN: A33E-06    [Abstracts]
TI: Recent observations on the vertical profiles of mixed-phase clouds during the Mixed Phase Cloud Experiment (MPACE) and the Alliance Icing Research Study (AIRS)-II
AU: * McFarquhar, G M
EM: mcfarq@atmos.uiuc.edu
AF: University of Illinois, Department of Atmospheric Sciences, 105 S. Gregory Street, Urbana, IL 61801-3070 United States
AU: Zhang, G
EM: gzhang2@atmos.uiuc.edu
AF: University of Illinois, Department of Atmospheric Sciences, 105 S. Gregory Street, Urbana, IL 61801-3070 United States
AU: Poellot, M
EM: poellot@aero.und.edu
AF: University of North Dakota, Department of Atmospheric Sciences , Grand Forks, ND 58202 United States
AU: Verlinde, J
EM: verlinde@meteo.psu.edu
AF: Penn State University, Department of Meteorology 516 Walker Building, University Park, PA 16802 United States
AU: Kok, G
EM: glkok@dropletmeasurement.com
AF: Droplet Measurement Technologies, 2400 Central Avenue, Boulder, CO 80301 United States
AU: Heymsfield, A
EM: heyms1@ucar.edu
AF: National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307
AB: Recent in-situ observations on the vertical profile of microphysical properties of mixed-phase clouds were obtained in the Arctic during MPACE by the University of North Dakota Citation and in mid-latitudes during AIRS II by the National Center for Atmospheric Research C-130. An algorithm applied to each 30 second sample of in-situ data identifies the phase as either ice, mixed, or liquid by assessing whether cloud particle images from the Cloud Particle Imager (CPI), the two-dimensional cloud probe (2DC) and high volume precipitation sampler (HVPS) are spherical, by determining if the voltage change of the Rosemount icing detector exceeds a given threshold, by examining the spectral shape of the small particle size distribution measured by the forward scattering spectrometer probe (FSSP) and by determining if the total water content measured by the Cloud Spectrometer and Impactor (CSI) or Counterflow Virtual Impactor (CVI) probes exceeds the liquid water content measured by a bulk water probe called the King probe. Size distributions are computed for the liquid and ice phases separately using data from the FSSP, the one-dimensional cloud probe (1DC), 2DC and HVPS. The in-situ data are also used to construct vertical profiles of how ice mass content, liquid water fraction, and effective radius of liquid and ice vary as a function of normalized cloud altitude for single-layer and multiple layer Arctic boundary layer stratus clouds observed during MPACE and for mid-latitude clouds observed during AIRS. The observed microphysical profiles are compared against profiles computed from parameterization schemes used in current large-scale models that depend on temperature and total water content, with the impact of differences assessed in terms of radiative forcing. The combination of measured bulk masses and size distributions also permits a comparison of the effective bulk densities for ice- and mixed-phase conditions against assumptions used in current models.
DE: 0320 Cloud physics and chemistry
DE: 0360 Radiation: transmission and scattering
DE: 3310 Clouds and cloud feedbacks
DE: 3311 Clouds and aerosols
DE: 3349 Polar meteorology
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005