Solve all chemical species with implicit solver

[fvitt]

It has been suggested (by @dkinnison) that all chemical species should be solved implicitly. This is a historical feature that was useful when computer resources were an issue.

This will require Cafe generated preprocessor input files for all chemical mechanisms in cam-chem/waccm. @lkemmons will need to supply the Cafe generated mechanisms files.

Should we remove the explicit solver from the code? Or should we leave the explicit solver option in for now?

[dan800]

I think it's worth a test to see if there are any unforeseen issues with making this switch in long integrations. Running a 2 degree CCMI simulation and comparing trends in constituents might be a good idea. But generally simplifying things seems like a good idea. @dkinnison might need to weigh in on how long a run would be needed.

re. removing the explicit solver - that seems like it's a rewrite of the chemical pre-processor, so not sure if it's worth it with MICM integration on the horizon. Unfortunately the word from Mary at the SIMA workshop this week is there's no timeline for that - could be 2 years away.

[lkemmons]

I have created new mechanism files from the cafe. NDEP and NHDEP were still listed in the explicit solver section - there must be something hardwired in the cafe somewhere. So, I manually edited the files and moved them to implicit. CAM-chem (trop_strat_mam4_vbs): /glade/u/home/emmons/mechanisms/ MZ301_TS1.1_simpleVBS_20211112.in WACCM: /glade/u/home/emmons/mechanisms/MZ302_TSMLT1.1_simpleVBS_20211112.in

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On Wed, Nov 10, 2021 at 4:24 PM Dan Marsh ***@***.***> wrote: I think it's worth a test to see if there are any unforeseen issues with making this switch in long integrations. Running a 2 degree CCMI simulation and comparing trends in constituents might be a good idea. But generally simplifying things seems like a good idea. @dkinnison <https://github.com/dkinnison> might need to weigh in on how long a run would be needed. re. removing the explicit solver - that seems like it's a rewrite of the chemical pre-processor, so not sure if it's worth it with MICM integration on the horizon. Unfortunately the word from Mary at the SIMA workshop this week is there's no timeline for that - could be 2 years away. — You are receiving this because you were assigned. Reply to this email directly, view it on GitHub <#466 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AH5BH7MWD4YIY6TD7UOJK63ULL5MRANCNFSM5HZDOJFA> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>.