气候变化领域集成服务门户(CCPortal): Improving Time Step Convergence in an Atmosphere Model With Simplified Physics: The Impacts of Closure Assumption and Process Coupling

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DOI	10.1029/2019MS001982
	Improving Time Step Convergence in an Atmosphere Model With Simplified Physics: The Impacts of Closure Assumption and Process Coupling
	Wan H.; Woodward C.S.; Zhang S.; Vogl C.J.; Stinis P.; Gardner D.J.; Rasch P.J.; Zeng X.; Larson V.E.; Singh B.
发表日期	2020
ISSN	19422466
卷号	12 期号:10
英文摘要	Convergence testing is a common practice in the development of dynamical cores of atmospheric models but is not as often exercised for the parameterization of subgrid physics. An earlier study revealed that the stratiform cloud parameterizations in several predecessors of the Energy Exascale Earth System Model (E3SM) showed strong time step sensitivity and slower-than-expected convergence when the model's time step was systematically refined. In this work, a simplified atmosphere model is configured that consists of the spectral-element dynamical core of the E3SM atmosphere model coupled with a large-scale condensation parameterization based on commonly used assumptions. This simplified model also resembles E3SM and its predecessors in the numerical implementation of process coupling and shows poor time step convergence in short ensemble tests. We present a formal error analysis to reveal the expected time step convergence rate and the conditions for obtaining such convergence. Numerical experiments are conducted to investigate the root causes of convergence problems. We show that revisions in the process coupling and closure assumption help to improve convergence in short simulations using the simplified model; the same revisions applied to a full atmosphere model lead to significant changes in the simulated long-term climate. This work demonstrates that causes of convergence issues in atmospheric simulations can be understood by combining analyses from physical and mathematical perspectives. Addressing convergence issues can help to obtain a discrete model that is more consistent with the intended representation of the physical phenomena. © 2020. The Authors.
英文关键词	atmospheric model; convergence; parameterization; time stepping
语种	英语
scopus关键词	Parameterization; Atmosphere modeling; Atmospheric simulations; Closure assumptions; Condensation parameterization; Convergence problems; Numerical experiments; Numerical implementation; Physical phenomena; Climate models; atmospheric modeling; climate change; cloud condensation nucleus; discrete element method; error analysis; long-term change; numerical method; parameterization; stratiform cloud
来源期刊	Journal of Advances in Modeling Earth Systems
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/156620
作者单位	Pacific Northwest National Laboratory, Richland, WA, United States; Lawrence Livermore National Laboratory, Livermore, CA, United States; Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ, United States; Department of Mathematical Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
推荐引用方式 GB/T 7714	Wan H.,Woodward C.S.,Zhang S.,et al. Improving Time Step Convergence in an Atmosphere Model With Simplified Physics: The Impacts of Closure Assumption and Process Coupling[J],2020,12(10).
APA	Wan H..,Woodward C.S..,Zhang S..,Vogl C.J..,Stinis P..,...&Singh B..(2020).Improving Time Step Convergence in an Atmosphere Model With Simplified Physics: The Impacts of Closure Assumption and Process Coupling.Journal of Advances in Modeling Earth Systems,12(10).
MLA	Wan H.,et al."Improving Time Step Convergence in an Atmosphere Model With Simplified Physics: The Impacts of Closure Assumption and Process Coupling".Journal of Advances in Modeling Earth Systems 12.10(2020).