气候变化领域集成服务门户(CCPortal): Impact of Lagrangian transport on lower-stratospheric transport timescales in a climate model

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DOI	10.5194/acp-20-15227-2020
	Impact of Lagrangian transport on lower-stratospheric transport timescales in a climate model
	Charlesworth E.J.; Dugstad A.-K.; Fritsch F.; Jöckel P.; Plöger F.
发表日期	2020
ISSN	1680-7316
起始页码	15227
结束页码	15245
卷号	20 期号:23
英文摘要	We investigate the impact of model trace gas transport schemes on the representation of transport processes in the upper troposphere and lower stratosphere. Towards this end, the Chemical Lagrangian Model of the Stratosphere (CLaMS) was coupled to the ECHAM/MESSy Atmospheric Chemistry (EMAC) model and results from the two transport schemes (Lagrangian critical Lyapunov scheme and fluxform semi-Lagrangian, respectively) were compared. Advection in CLaMS was driven by the EMAC simulation winds, and thereby the only differences in transport between the two sets of results were caused by differences in the transport schemes. To analyze the timescales of large-scale transport, multiple tropical-surface-emitted tracer pulses were performed to calculate age of air spectra, while smaller-scale transport was analyzed via idealized, radioactively decaying tracers emitted in smaller regions (nine grid cells) within the stratosphere. The results show that stratospheric transport barriers are significantly stronger for Lagrangian EMACCLaMS transport due to reduced numerical diffusion. In particular, stronger tracer gradients emerge around the polar vortex, at the subtropical jets, and at the edge of the tropical pipe. Inside the polar vortex, the more diffusive EMAC flux-form semi-Lagrangian transport scheme results in a substantially higher amount of air with ages from 0 to 2 years (up to a factor of 5 higher). In the lowermost stratosphere, mean age of air is much smaller in EMAC, owing to stronger diffusive cross-tropopause transport. Conversely, EMAC-CLaMS shows a summertime lowermost stratosphere age inversion - a layer of older air residing below younger air (an "eave"). This pattern is caused by strong poleward transport above the subtropical jet and is entirely blurred by diffusive crosstropopause transport in EMAC. Potential consequences from the choice of the transport scheme on chemistry-climate and geoengineering simulations are discussed. © 2020 BMJ Publishing Group. All rights reserved.
英文关键词	atmospheric chemistry; atmospheric transport; climate modeling; jet; stratosphere; timescale; trace gas
语种	英语
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/168900
作者单位	Forschungszentrum Jülich, IEK-7 Stratosphäre, Jülich, Germany; Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany; Institut für Atmosphären- und Umweltforschung, Universität Wuppertal, Wuppertal, Germany
推荐引用方式 GB/T 7714	Charlesworth E.J.,Dugstad A.-K.,Fritsch F.,et al. Impact of Lagrangian transport on lower-stratospheric transport timescales in a climate model[J],2020,20(23).
APA	Charlesworth E.J.,Dugstad A.-K.,Fritsch F.,Jöckel P.,&Plöger F..(2020).Impact of Lagrangian transport on lower-stratospheric transport timescales in a climate model.Atmospheric Chemistry and Physics,20(23).
MLA	Charlesworth E.J.,et al."Impact of Lagrangian transport on lower-stratospheric transport timescales in a climate model".Atmospheric Chemistry and Physics 20.23(2020).