CMIP7 historical stratospheric aerosol optical properties and volcanic stratospheric sulfur emissions

[thomasaubry]

This discussion is the place for all things stratospheric aerosol optical properties and volcanic stratospheric sulfur emissions!

Please check our rough documentation for these datasets including version history, dataset description and implementation recommendation, comparison with CMIP6 dataset and FAQ. You can comment in this Github discussion and/or on this document. The document is currently being improved and will be kept up to date as we release new versions; thanks for your patience! :)

The latest version of our datasets (1.3.0) includes piControl climatology files for aerosol optical properties. It also includes small-magnitude eruption pre-satellite era. This means that the picontrol climatology mean forcing should be very stable from now on. Should you use version 1.3.0 to start spinning up your models, we expect minor impacts when you switch to future updates include the final version frozen for CMIP7 Fast Track late February 2025.

For some analysis and discussion of our dataset at version 1.1.3, you can check out this discussion kindly initiated by Shipeng Zhang.

Should any comment/question you leave be left unanswered for longer than you wish, please contact Thomas Aubry ([email protected]).

[MartineMichou]

Dear Dr. Aubry,

Dealing with the stratospheric volcano information you provided for CMIP6Plus we have two questions:

• in the CMIP6 volcano dataset there was an H2SO4 _mass field (molecules/cm3air) that corresponded to H2SO4 in the condensed phase.
  As our climate model uses this variable can you provide it on the same coordinates as the other fields?

• again, in the CMIP6 volcano dataset there were two sad fields, one called sad, and the other one sad_of_big_particles. We used the sad_of_big_particles field in our CMIP6 simulations.
  Can you provide sad_of_big_particles in addition to sad?

Looking forward to your response,

Martine Michou

[thomasaubry]

Dear Martine,
Replying on Github as well so that anyone with similar questions can see the answers.

1. For the aerosol number density (former H2SO4_msss field), we will provide it in the next version. I'm hoping to share an update through my own archive by the end of this week (Feb 7) and it should be on ESGF by early next week (~Feb 11). If you need me to accelerate this timeline please let me know and I will do my best (but travelling/working part time this week)
2. For the sad_of_big_particles field, it sounded from our discussion that you might not need it in the end. SHould any modelling group need this variable, please point me to documentation that enables me to understand your need as I cannot find this variable in any CMIP6 documentation.
   Merci!
   Thomas

[thomasaubry]

Hello,

Just confirming the number density is now added in version 1.3.1. This version is undergoing validation before being uploaded to ESGF, it should be there by Weds Feb 12 I suspect. If anyone wants a copy of the files (which at the moment have not been quality checked), please email [email protected] and I should come back to you on the same day.

All the best,

Thomas

[mdeushiMRI]

Dear Dr. Aubry,

Our climate model also uses the H2SO4 _mass field (molecules/cm3air).
Could you provide H2SO4 _mass data, please?

Thank you in advance.

Makoto Deushi.

[thomasaubry]

Dear Makoto,
Thanks a lot for this note. Please see my reply to Martine and let me know if you have any concern with the timeline. If you provide me with your email address (email [email protected]) I can share updated files before they are quality-checked and uploaded to ESGF.
All the best,
Thomas