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DOI	10.5194/acp-19-6295-2019
	Cloud droplet growth in shallow cumulus clouds considering 1-D and 3-D thermal radiative effects
	Klinger C.; Feingold G.; Yamaguchi T.
发表日期	2019
ISSN	16807316
起始页码	6295
结束页码	6313
卷号	19 期号:9
英文摘要	The effect of 1-D and 3-D thermal radiation on cloud droplet growth in shallow cumulus clouds is investigated using large eddy simulations with size-resolved cloud microphysics. A two-step approach is used for separating microphysical effects from dynamical feedbacks. In step one, an offline parcel model is used to describe the onset of rain. The growth of cloud droplets to raindrops is simulated with bin-resolved microphysics along previously recorded Lagrangian trajectories. It is shown that thermal heating and cooling rates can enhance droplet growth and raindrop production. Droplets grow to larger size bins in the 10-30 μm radius range. The main effect in terms of raindrop production arises from recirculating parcels, where a small number of droplets are exposed to strong thermal cooling at cloud edge. These recirculating parcels, comprising about 6 %-7 % of all parcels investigated, make up 45 % of the rain for the no-radiation simulation and up to 60 % when 3-D radiative effects are considered. The effect of 3-D thermal radiation on rain production is stronger than that of 1-D thermal radiation. Three-dimensional thermal radiation can enhance the rain amount up to 40 % compared to standard droplet growth without radiative effects in this idealized framework. In the second stage, fully coupled large eddy simulations show that dynamical effects are stronger than microphysical effects, as far as the production of rain is concerned. Three-dimensional thermal radiative effects again exceed one-dimensional thermal radiative effects. Small amounts of rain are produced in more clouds (over a larger area of the domain) when thermal radiation is applied to microphysics. The dynamical feedback is shown to be an enhanced cloud circulation with stronger subsiding shells at the cloud edges due to thermal cooling and stronger updraft velocities in the cloud center. It is shown that an evaporation-circulation feedback reduces the amount of rain produced in simulations where 3-D thermal radiation is applied to microphysics and dynamics, in comparison to where 3-D thermal radiation is only applied to dynamics. © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License.
语种	英语
scopus关键词	cloud droplet; cloud microphysics; cloud radiative forcing; cooling; cumulus; heating
来源期刊	Atmospheric Chemistry and Physics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/144420
作者单位	Chemical Sciences Division, NOAA Earth System Research Laboratory (ESRL), Boulder, CO, United States; Ludwig-Maximilians-Universität München, Lehrstuhl für Experimentelle Meteorologie, Munich, Germany; Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, United States
推荐引用方式 GB/T 7714	Klinger C.,Feingold G.,Yamaguchi T.. Cloud droplet growth in shallow cumulus clouds considering 1-D and 3-D thermal radiative effects[J],2019,19(9).
APA	Klinger C.,Feingold G.,&Yamaguchi T..(2019).Cloud droplet growth in shallow cumulus clouds considering 1-D and 3-D thermal radiative effects.Atmospheric Chemistry and Physics,19(9).
MLA	Klinger C.,et al."Cloud droplet growth in shallow cumulus clouds considering 1-D and 3-D thermal radiative effects".Atmospheric Chemistry and Physics 19.9(2019).