Atmos. Chem. Phys., 13, 5631-5645, 2013
www.atmos-chem-phys.net/13/5631/2013/
doi:10.5194/acp-13-5631-2013
© Author(s) 2013. This work is distributed
under the Creative Commons Attribution 3.0 License.
Large-eddy simulation of organized precipitating trade wind cumulus clouds
A. Seifert1 and T. Heus2
1Hans-Ertel Centre for Weather Research, Deutscher Wetterdienst, Hamburg, Germany
2Max Planck Institute for Meteorology, Hamburg, Germany

Abstract. Trade wind cumulus clouds often organize in along-wind cloud streets and across-wind mesoscale arcs. We present a benchmark large-eddy simulation which resolves the individual clouds as well as the mesoscale organization on scales of O(10 km). Different methods to quantify organization of cloud fields are applied and discussed. Using perturbed physics large-eddy simulation experiments, the processes leading to the formation of cloud clusters and the mesoscale arcs are revealed. We find that both cold pools as well as the sub-cloud layer moisture field are crucial to understand the organization of precipitating shallow convection. Further sensitivity studies show that microphysical assumptions can have a pronounced impact on the onset of cloud organization.

Citation: Seifert, A. and Heus, T.: Large-eddy simulation of organized precipitating trade wind cumulus clouds, Atmos. Chem. Phys., 13, 5631-5645, doi:10.5194/acp-13-5631-2013, 2013.
 
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