Impact of Lagrangian Transport on Lower-Stratospheric Transport Time Scales in a Climate Model

doi:10.5194/acp-2020-458

GSTDTAP > 地球科学

DOI	10.5194/acp-2020-458
	Impact of Lagrangian Transport on Lower-Stratospheric Transport Time Scales in a Climate Model
	Edward J. Charlesworth, Ann-Kristin Dugstad, Frauke Fritsch, Patrick Jöckel, and Felix Plöger
	2020-07-09
发表期刊	Atmospheric Chemistry and Physics
出版年	2020
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 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 time scales 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 EMAC-CLaMS 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 5 higher). In the lowermost stratosphere, air is much younger 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 cross-tropopause transport in EMAC. Potential consequences from the choice of the transport scheme on CCM and geoengineering simulations are discussed.
领域	地球科学
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文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/283244
专题	地球科学
推荐引用方式 GB/T 7714	Edward J. Charlesworth, Ann-Kristin Dugstad, Frauke Fritsch, Patrick Jöckel, and Felix Plöger. Impact of Lagrangian Transport on Lower-Stratospheric Transport Time Scales in a Climate Model[J]. Atmospheric Chemistry and Physics,2020.
APA	Edward J. Charlesworth, Ann-Kristin Dugstad, Frauke Fritsch, Patrick Jöckel, and Felix Plöger.(2020).Impact of Lagrangian Transport on Lower-Stratospheric Transport Time Scales in a Climate Model.Atmospheric Chemistry and Physics.
MLA	Edward J. Charlesworth, Ann-Kristin Dugstad, Frauke Fritsch, Patrick Jöckel, and Felix Plöger."Impact of Lagrangian Transport on Lower-Stratospheric Transport Time Scales in a Climate Model".Atmospheric Chemistry and Physics (2020).