Mean age from observations in the lowermost stratosphere: an improved method and interhemispheric differences

Wagenhäuser, Thomas; Jesswein, Markus; Keber, Timo; Schuck, Tanja; Engel, Andreas

doi:https://doi.org/10.5194/acp-23-3887-2023

Articles | Volume 23, issue 7

https://doi.org/10.5194/acp-23-3887-2023

© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-23-3887-2023

© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 23, issue 7

Research article

|

03 Apr 2023

Research article |

| 03 Apr 2023

Mean age from observations in the lowermost stratosphere: an improved method and interhemispheric differences

Thomas Wagenhäuser, Markus Jesswein, Timo Keber, Tanja Schuck, and Andreas Engel

Supplement

https://doi.org/10.5194/acp-23-3887-2023-supplement

Data sets

SF6 and CFC-12 measurements and mean age along HALO flight tracks during PGS, WISE and SouthTRAC T. Wagenhäuser, M. Jesswein, T. Keber, T. Schuck, A. Engel, and J.-U. Grooß https://doi.org/10.5281/zenodo.7275822

Model code and software

exTR-TR-method Python code T. Wagenhäuser and A. Engel https://doi.org/10.5281/zenodo.7267203

origin fraction parameterization Python code T. Wagenhäuser https://doi.org/10.5281/zenodo.7267114

sf6-timeshifts-from-rigby2010 Python code T. Wagenhäuser https://doi.org/10.5281/zenodo.7267089

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Short summary

A common assumption to derive mean age from trace gas observations is that all air enters the stratosphere through the tropical tropopause. Using SF₆ as an age tracer, this leads to negative mean age values close to the Northern Hemispheric extra-tropical tropopause. Our improved method also considers extra-tropical input into the stratosphere. More realistic values are derived using this method. Interhemispheric differences in mean age are found when comparing data from two aircraft campaigns.