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DOI	10.5194/acp-19-5269-2019
	Deriving stratospheric age of air spectra using an idealized set of chemically active trace gases
	Hauck M.; Fritsch F.; Garny H.; Engel A.
发表日期	2019
ISSN	16807316
起始页码	5269
结束页码	5291
卷号	19 期号:7
英文摘要	Analysis of stratospheric transport from an observational point of view is frequently realized by evaluation of the mean age of air values from long-lived trace gases. However, this provides more insight into general transport strength and less into its mechanism. Deriving complete transit time distributions (age spectra) is desirable, but their deduction from direct measurements is difficult. It is so far primarily based on model work. This paper introduces a modified version of an inverse method to infer age spectra from mixing ratios of short-lived trace gases and investigates its basic principle in an idealized model simulation. For a full description of transport seasonality the method includes an imposed seasonal cycle to gain multimodal spectra. An ECHAM/MESSy Atmospheric Chemistry (EMAC) model simulation is utilized for a general proof of concept of the method and features an idealized dataset of 40 radioactive trace gases with different chemical lifetimes as well as 40 chemically inert pulsed trace gases to calculate pulse age spectra. It is assessed whether the modified inverse method in combination with the seasonal cycle can provide matching age spectra when chemistry is well-known. Annual and seasonal mean inverse spectra are compared to pulse spectra including first and second moments as well as the ratio between them to assess the performance on these timescales. Results indicate that the modified inverse age spectra match the annual and seasonal pulse age spectra well on global scale beyond 1.5 years of mean age of air. The imposed seasonal cycle emerges as a reliable tool to include transport seasonality in the age spectra. Below 1.5 years of mean age of air, tropospheric influence intensifies and breaks the assumption of single entry through the tropical tropopause, leading to inaccurate spectra, in particular in the Northern Hemisphere. The imposed seasonal cycle wrongly prescribes seasonal entry in this lower region and does not lead to a better agreement between inverse and pulse age spectra without further improvement. Tests with a focus on future application to observational data imply that subsets of trace gases with 5 to 10 species are sufficient for deriving well-matching age spectra. These subsets can also compensate for an average uncertainty of up to ±20% in the knowledge of chemical lifetime if a deviation of circa ±10% in modal age and amplitude of the resulting spectra is tolerated. © 2019 Author(s).
语种	英语
scopus关键词	atmospheric chemistry; atmospheric transport; Northern Hemisphere; seasonality; stratosphere; trace gas; tropopause
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/144475
作者单位	Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, Frankfurt am Main, Germany; Deutsches Zentrum für Luft-und Raumfahrt (DLR), Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany; Meteorological Institute Munich, Ludwig Maximilian University of Munich, Munich, Germany
推荐引用方式 GB/T 7714	Hauck M.,Fritsch F.,Garny H.,et al. Deriving stratospheric age of air spectra using an idealized set of chemically active trace gases[J],2019,19(7).
APA	Hauck M.,Fritsch F.,Garny H.,&Engel A..(2019).Deriving stratospheric age of air spectra using an idealized set of chemically active trace gases.Atmospheric Chemistry and Physics,19(7).
MLA	Hauck M.,et al."Deriving stratospheric age of air spectra using an idealized set of chemically active trace gases".Atmospheric Chemistry and Physics 19.7(2019).