HR: 1340h
AN: A33A-0869 [Abstracts]
TI: The effect of large CCN on drizzle and precipitation production efficiency, United Arab Emirates case
study
AU: * Salazar, V
EM: vidal@ucar.edu
AF: National Center for Atmospheric Research, Research Applications Laboratory 3450 Mitchell Lane, Boulder,
CO 80301
AU: Bruintjes, R T
EM: roelof@ucar.edu
AF: National Center for Atmospheric Research, Research Applications Laboratory 3450 Mitchell Lane, Boulder,
CO 80301
AU: Ross, K E
EM: ross@ucar.edu
AF: University of the Witwatersrand, Climatology Research Group, Johannesburg, 2090
South Africa
AU: Breed, D
EM: breed@ucar.edu
AF: National Center for Atmospheric Research, Research Applications Laboratory 3450 Mitchell Lane, Boulder,
CO 80301
AU: Jensen, T
EM: jensen@ucar.edu
AF: National Center for Atmospheric Research, Research Applications Laboratory 3450 Mitchell Lane, Boulder,
CO 80301
AB:
Several recent theoretical and observational studies have shown that large cloud condensation nuclei (CCN) ingested into
clouds cause a broadening in the cloud droplet spectrum and accelerate the production of raindrops by coalescence. In
particular, the numerical studies highlighted the importance of drizzle formation in the subsequent production of rain.
The effects of size and chemistry of large CCN (diameter >1 micron) on the production of drizzle and rain production in
warm clouds is investigated using the one-dimensional cloud parcel developed by Cooper et al. (1997). The model was modified
for this study to include an improved representation of the aerosol chemistry and CCN characteristics measured during the
United Arab Emirates Rainfall Enhancement Assessment Program field projects. Several scenarios are tested in the model,
based on the in-situ observations collected during the field projects. For example, characteristics from coastal,
industrial, inland, desert and mountain profiles are used to initialize the model calculations. The model results are
compared with the observations to further evaluate the field project results.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005