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标题：Exploring bin‐macrophysics models for moist convective transport and clouds
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作者：R. A. J. Neggers
期刊名称：Journal of Advances in Modeling Earth Systems
电子版ISSN：1942-2466
出版年度：2015
卷号：7
期号：4
页码：2079-2104
DOI：10.1002/2015MS000502
出版社：John Wiley & Sons, Ltd.
摘要：This study explores a mass flux framework for moist convective transport and clouds that is formulated in terms of discretized size densities. The properties of each bin in these histograms are estimated individually, making use of a rising plume model. In this framework, the number density acts as a weight, appearing in the area fraction of the mass flux. Such “bin‐macrophysics” models have the benefit that bulk closures become redundant, and that scale‐awareness is introduced at the basis of the formulation. Large‐eddy simulation results are used to verify the design of this framework and to constrain associated constants of proportionality. The behavior of the framework is explored by means of single‐column model simulations of various idealized cases of shallow and deeper surface‐driven convection. A smoothly developing solution for a deepening marine shallow cumulus case is obtained, reproducing key aspects of transport and clouds that define this regime. Further investigation of the size statistics of the framework reveals that indirect interactions between size‐bins play a key role in the equilibration process. An “acceleration‐detrainment” layer is identified above cloud base in which the flux uptake by the largest plumes is counteracted by the detrainment by decelerating smaller plumes. This suppresses CIN, and thus acts to preserve the cloud‐subcloud coupling. The convective mass flux shows sensitivity to environmental humidity in the deeper convective cases, reproducing transitions from shallow‐to‐deep convection. Sensitivity tests are performed to assess the impact of various components of the framework.
关键词：mass flux;moist convection;macrophysics;EDMF;parameterization