10/12/2010
Turning Shallow Puffy Clouds into Deep Showering Clouds
Summary
DOE scientists used ARM Climate Research Facility long-term comprehensive observations from the Southern Great Plains site to systematically test theories for the transition of midday shallow puffy clouds to late-afternoon deep clouds that rain intensely. They found strong observational support for theories involving convection dynamics, lateral entrainment, and the increase of atmospheric moisture in the first few miles above the ground before the transition to deep clouds begin. They also confirmed the effect of surface conditions variability in the initiation and maintenance of deep clouds. This study is among the first to comprehensively validate these theories over land using ARM Climate Research Facility observational data. These observations and conclusions will be used to improve the representation of convective clouds in cloud-resolving climate models, addressing the well-known issues with the prediction of late-afternoon deep clouds and rain over land.
References
Zhang, Y. and S. A. Klein. 2010. “Mechanisms affecting the transition from shallow to deep convection over land: Inferences from observations of the diurnal cycle collected at the ARM Southern Great Plains site,” Journal of the Atmospheric Sciences, 67(9), 2943-2959.