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Simulating age of air and the distribution of SF$_{6}$ in the stratosphere with the SILAM model

Kouznetsov, Rostislav; Sofiev, Mikhail; Vira, Julius; Stiller, Gabriele

Abstract:
he paper presents a comparative study of age of air (AoA) derived from several approaches: a widely used passive-tracer accumulation method, the SF6 accumulation, and a direct calculation of an ideal-age tracer. The simulations were performed with the Eulerian chemistry transport model SILAM driven with the ERA-Interim reanalysis for 1980–2018.
The Eulerian environment allowed for simultaneous application of several approaches within the same simulation and interpretation of the obtained differences. A series of sensitivity simulations revealed the role of the vertical profile of turbulent diffusion in the stratosphere, destruction of SF$_{6}$ in the mesosphere, and the effect of gravitational separation of gases with strongly different molar masses.
The simulations reproduced well the main features of the SF$_{6}$ distribution in the atmosphere observed by the MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) satellite instrument. It was shown that the apparent very old air in the upper stratosphere derived from the SF$_{6}$ profile observations is a result of destruction and gravitational separation of this gas in the upper stratosphere and the mesosphere. ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000120319
Veröffentlicht am 19.06.2020
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Meteorologie und Klimaforschung - Atmosphärische Spurenstoffe und Fernerkundung (IMK-ASF)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2020
Sprache Englisch
Identifikator ISSN: 1680-7324
KITopen-ID: 1000120319
Erschienen in Atmospheric chemistry and physics
Band 20
Heft 9
Seiten 5837–5859
Vorab online veröffentlicht am 15.05.2020
Nachgewiesen in Web of Science
Scopus
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