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VERTICAL TRANSPORT BY CUMULUS CLOUDS
Citation:
Ching, J.K.S. AND A. Alkezweeny. VERTICAL TRANSPORT BY CUMULUS CLOUDS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/D-86/001 (NTIS PB86144607).
Description:
The exchange process between the mixed layer and the free troposphere by non precipitating cumulus convective clouds is examined based on results of two field experiments conducted in Lexington, Kentucky. The first experiment utilized SF6 tracer gas released from one aircraft and sampled by another at various levels in and above the mixed layer as well as on the ground. The results suggest that the cloud convective activity force cloud layer air back into the mixed layer and into its surface layer. Thus, the layer of turbulent mixing is deeper and more vigorous in the presence of convective clouds, and the turbulence variance statistics near the surface are apt to contain large, but episodic variability localized within the domain of cloudiness. The observation is shown to be a consequence of and a requirement for a net upward flux of pollutants at the top of the mixed layer.