Age of air diagnostic in GCHP?

[mcdonh1718]

Your name

Helena McDonald

Your affiliation

MIT

Please provide a clear and concise description of your question or discussion topic.

I'm working on an experiment looking at chemical impact of some emissions in the stratosphere. I'm wondering if GCHP has a diagnostic where I can extract the mean age of air for a given gridcell; I want to be able to comment on the stratospheric circulation strength. Based on the documentation it doesn't look like this exists, but I wanted to double check. Is there a way I could extract this directly from the transport mechanism?

[lizziel]

Hi @mcdonh1718, there is an age-of-air tracer in the transport tracer simulation. I believe you can simply add it to your advected species list in geoschem_config.yml to include it. @msulprizio, could you confirm that? More information about the species, including its name and description, are at https://wiki.seas.harvard.edu/geos-chem/index.php/TransportTracers_simulation.

[msulprizio]

I believe you can simply add it to your advected species list in geoschem_config.yml to include it. @msulprizio, could you confirm that?

Yes, that should work. You may also need to change the time cycle flag for the restart file entry in HEMCO_Config.rc from EFYO to CYS to avoid having the simulation crash because it can't find that species in the restart file.