8.3A Understanding cirrus cloud behavior using observations from A-Train and geostationary satellite and NCEP/NCAR reanalysis data

Wednesday, 30 June 2010: 11:00 AM
Cascade Ballroom (DoubleTree by Hilton Portland)
Elizabeth J. Dupont, University of Utah, Salt Lake City, UT; and G. G. Mace

Knowledge of how large-scale dynamics are coupled with microphysical properties is necessary for parameterizing cirrus in climate models. Atlantic cirrus events observed by the CloudSat and CALIPSO satellites are sorted into different groups using a k-means cluster analysis. The cirrus events are classified based on six meteorological parameters derived from the NCEP/NCAR reanalysis: 300mb relative humidity, 300mb omega, 300mb moisture flux convergence, 500mb omega, 500mb absolute vorticity advection, and 850mb temperature advection. To characterize the tendencies of cirrus events within the dynamical regimes, the SEVIRI Imager on the Meteosat satellite is used to track cirrus events in time by following patterns of 6.2µm brightness temperatures. Cirrus events are defined as growing/dissipating based on how the brightness temperature of the cloud area changed in time. The composite dynamics of each cirrus cluster are investigated to determine how the large-scale meteorology plays a role in the evolution of the cirrus events. The microphysics associated with the cirrus clusters is investigated with composite profiles of total water content from cloud base to cloud top. Differences in how the total water content varies with normalized layer depth for growing and dissipating cirrus events may provide insight into the processes that maintain these clouds.
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