气候变化领域集成服务门户(CCPortal): Understanding the Moisture Variance in Precipitating Shallow Cumulus Convection

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DOI	10.1029/2019JD031178
	Understanding the Moisture Variance in Precipitating Shallow Cumulus Convection
	Anurose T.J.; Bašták Ďurán I.; Schmidli J.; Seifert A.
发表日期	2020
ISSN	2169897X
卷号	125 期号:1
英文摘要	The impact of precipitation in shallow cumulus convection on the moisture variance and third-order moments of moisture is investigated with the help of large-eddy simulations. Three idealized simulations based on the Rain in Cumulus over the Ocean field experiment are analyzed: one nonprecipitating, on a smaller domain, and two precipitating cases, on a larger domain with different initial profiles of moisture. Results show that precipitation and the associated cloud organization lead to increased generation of higher-order moments (HOM) of moisture compared to the nonprecipitating case. To understand the physical mechanism and the role of individual processes in this increase, budgets of HOM of moisture are studied. Microphysics directly decreases the generation of HOM of moisture, but this effect is not dominant. The gradient production term is identified as the main source term in the HOM budgets. The influence of the gradient production term on moisture variance is further examined separately in cloud active and nonactive regions. The main contribution to the gradient production term comes from the smaller cloud active region because of the stronger moisture flux. Further analyses of the horizontal and vertical cross sections of moisture fluctuations show that the precipitation-induced downdrafts and updrafts are the main mechanism for the generation of moisture variance. The variance increase is linked to shallow dry downdraft regions with horizontal divergence in the subcloud layer, moist updrafts with horizontal convergence in the bulk cloud layer, and finally wider areas of horizontal divergence in the cloud inversion layer. ©2019. The Authors.
英文关键词	Atmospheric boundary layer; Large eddy simulation; Shallow cumulus convection; Turbulent budget
语种	英语
来源期刊	Journal of Geophysical Research: Atmospheres
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/186235
作者单位	Institute for Atmospheric and Environmental Sciences, Goethe-University, Frankfurt am Main, Germany; Deutscher Wetterdienst, Offenbach, Germany
推荐引用方式 GB/T 7714	Anurose T.J.,Bašták Ďurán I.,Schmidli J.,et al. Understanding the Moisture Variance in Precipitating Shallow Cumulus Convection[J],2020,125(1).
APA	Anurose T.J.,Bašták Ďurán I.,Schmidli J.,&Seifert A..(2020).Understanding the Moisture Variance in Precipitating Shallow Cumulus Convection.Journal of Geophysical Research: Atmospheres,125(1).
MLA	Anurose T.J.,et al."Understanding the Moisture Variance in Precipitating Shallow Cumulus Convection".Journal of Geophysical Research: Atmospheres 125.1(2020).