CMIP7 Historical Forcings are part of the DECK

[johndunne13]

Dataset source ID(s)

Dataset source ID(s):

Describe the issue

This githip page site https://input4mips-cvs.readthedocs.io/en/latest/dataset-overviews/ currently incorrectly refers to the historical forcings as part of "CMIP7 AR7 Fast Track". As discussed in the CMIP7 description paper, the CMIP Panel highlights the importance of the Historical simulation for CMIP7 by including it in the mandatory DECK set of experiments rather than any optional set of experiments. The github page should be corrected to reflect this distinction and avoid confusion. Thanks! John

Expected data

Screenshots

Additional context

[znichollscr]

Hi @johndunne13, just to make sure we're all on the same page. You're saying that there is only one DECK. So, unlike other MIPs, which could have a fast track phase and a later phase, for the DECK simulations there is only one phase. Key implication: the DECK forcings that are being released now are the only DECK forcings that will be released throughout the entirety of CMIP7 (at least under the title of the DECK).

If yes, that's good to understand. Can you please also confirm that this does not need to go through a CMIP panel meeting, I should just update the docs now.

[johndunne13]

Yes, my understanding is that the proposal CMIP presented and ratified by WCRP at the Hamburg meeting last year is for a single mandatory DECK (including the historical) across CMIP's 7th phase. ccing Eleanor and Helene to correct me if I have mischaracterized anything, but this would not require any new CMIP Panel discussion.

…

On Fri, Mar 14, 2025 at 12:17 PM znichollscr ***@***.***> wrote: Hi @johndunne13 <https://github.com/johndunne13>, just to make sure we're all on the same page. You're saying that there is only one DECK. So, unlike other MIPs, which could have a fast track phase and a later phase, for the DECK simulations there is only one. Key implication: the DECK forcings that are being released now are the only DECK forcings that will be released throughout the entirety of CMIP7 (at least under the title of the DECK). If yes, that's good to understand. Can you please also confirm that this does not need to go through a CMIP panel meeting, I should just update the docs now. — Reply to this email directly, view it on GitHub <#222 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AGUJAMRXAYXAZOPXBL3JYIL2UL6I5AVCNFSM6AAAAABZA7NQC2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDOMRVGE2TSMBSG4> . You are receiving this because you were mentioned.Message ID: ***@***.***> [image: znichollscr]*znichollscr* left a comment (PCMDI/input4MIPs_CVs#222) <#222 (comment)> Hi @johndunne13 <https://github.com/johndunne13>, just to make sure we're all on the same page. You're saying that there is only one DECK. So, unlike other MIPs, which could have a fast track phase and a later phase, for the DECK simulations there is only one. Key implication: the DECK forcings that are being released now are the only DECK forcings that will be released throughout the entirety of CMIP7 (at least under the title of the DECK). If yes, that's good to understand. Can you please also confirm that this does not need to go through a CMIP panel meeting, I should just update the docs now. — Reply to this email directly, view it on GitHub <#222 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AGUJAMRXAYXAZOPXBL3JYIL2UL6I5AVCNFSM6AAAAABZA7NQC2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDOMRVGE2TSMBSG4> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[johndunne13]

OFFICIAL I agree – only one DECK.

…

--- Prof. Helene Hewitt OBE (she/her) Met Office Science Fellow: Ocean, Cryosphere and Climate Co-chair of Coupled Model Intercomparison Project (CMIP) Panel Met Office FitzRoy Road Exeter Devon EX1 3PB United Kingdom Tel: +44 (0)1392 884956 Email: ***@***.******@***.***> Website: www.metoffice.gov.uk<http://www.metoffice.gov.uk/> Visiting Professor at University of Southampton Adjunct Fellow at National Oceanography Centre Professeure Invitee Benevolee University of Geneva OFFICIAL From: John Dunne - NOAA Federal ***@***.***> Sent: 14 March 2025 16:27 To: PCMDI/input4MIPs_CVs ***@***.***> Cc: PCMDI/input4MIPs_CVs ***@***.***>; Mention ***@***.***>; Eleanor O'Rourke ***@***.***>; Helene Hewitt ***@***.***> Subject: Re: [PCMDI/input4MIPs_CVs] CMIP7 Historical Forcings are part of the DECK (Issue #222) Yes, my understanding is that the proposal CMIP presented and ratified by WCRP at the Hamburg meeting last year is for a single mandatory DECK (including the historical) across CMIP's 7th phase. ccing Eleanor and Helene to correct me if I have mischaracterized anything, but this would not require any new CMIP Panel discussion. On Fri, Mar 14, 2025 at 12:17 PM znichollscr ***@***.******@***.***>> wrote: Hi @johndunne13<https://github.com/johndunne13>, just to make sure we're all on the same page. You're saying that there is only one DECK. So, unlike other MIPs, which could have a fast track phase and a later phase, for the DECK simulations there is only one. Key implication: the DECK forcings that are being released now are the only DECK forcings that will be released throughout the entirety of CMIP7 (at least under the title of the DECK). If yes, that's good to understand. Can you please also confirm that this does not need to go through a CMIP panel meeting, I should just update the docs now. — Reply to this email directly, view it on GitHub<#222 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AGUJAMRXAYXAZOPXBL3JYIL2UL6I5AVCNFSM6AAAAABZA7NQC2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDOMRVGE2TSMBSG4>. You are receiving this because you were mentioned.Message ID: ***@***.******@***.***>> [znichollscr]znichollscr left a comment (PCMDI/input4MIPs_CVs#222)<#222 (comment)> Hi @johndunne13<https://github.com/johndunne13>, just to make sure we're all on the same page. You're saying that there is only one DECK. So, unlike other MIPs, which could have a fast track phase and a later phase, for the DECK simulations there is only one. Key implication: the DECK forcings that are being released now are the only DECK forcings that will be released throughout the entirety of CMIP7 (at least under the title of the DECK). If yes, that's good to understand. Can you please also confirm that this does not need to go through a CMIP panel meeting, I should just update the docs now. — Reply to this email directly, view it on GitHub<#222 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AGUJAMRXAYXAZOPXBL3JYIL2UL6I5AVCNFSM6AAAAABZA7NQC2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDOMRVGE2TSMBSG4>. You are receiving this because you were mentioned.Message ID: ***@***.******@***.***>>

[durack1]

Just flagging that even for CMIP6, the DECK was identified "continuous" - such as the graphic below. We need to be a little careful about conflating "entry card" (CMIP6 terminology) which relates to what a modelling group needs to do to contribute to CMIP7, and what forcing data is used to generate the simulations - with all likelihood being that there will be updates to forcing data over the lifetime of CMIP7, which will likely start with first data available in 2025, and if precedents are a guide, extend well past 2030..

[durack1]

A key point to note, is that in CMIP6 any simulations that met the CMIP6 data specifications were allowed to publish their data into the CMIP6 ESGF project. We have no technical way to validate what forcing data was used for a piControl, historical (or their esm* variants), and consequently we will get what we get in the CMIP7 archive - this is an "ensemble of opportunity" after all!

Most, but not all modeling groups used the CMIP6 provided forcings (e.g. Lurton et al., 2020), but some groups did not (e.g. Danabasoglu et al., 2020 note the VolcanEESM volcanic forcing was used, not the Luo et al data provided in input4MIPs). Both these sims are published side-by-side in CMIP6, and it is likely the same will happen in CMIP7

[znichollscr]

there will be updates to forcing data over the lifetime of CMIP7

My understanding is that the communications made to date are saying the opposite of this. We are freezing the forcings for the historical. There will be no updates as part of the DECK (i.e. if you want to do updates, do them in a MIP).

@durack1 are you arguing for us to put back in the distinction between CMIP7/fast track/whatever comes now? If no, I'm a bit confused about the point being made, I thought we had clarity about the next steps (drop fast track) but now I'm not sure.

[vnaik60]

1. there will be "updates to forcing data over the lifetime of CMIP7" but most modeling centers will not rerun DECK simualtions for the CMIP7 phase. New simulations could be run as part of CMIP7Plus or CMIP8. Running DECK is costly.
2. there will be extensions to forcings during CMIP7 and most modeling centers could extend their historical (hist-ext) simulations if they choose to. This would entail minimum cost.
   my 2 cents.

[znichollscr]

1. there will be "updates to forcing data over the lifetime of CMIP7" but most modeling centers will not rerun DECK simualtions for the CMIP7 phase. New simulations could be run as part of CMIP7Plus or CMIP8. Running DECK is costly.

Ok, so surely we put those updates under a mip_era of "CMIP7Plus" to make clear that we do not expect modelling centres to re-run?

2. there will be extensions to forcings during CMIP7 and most modeling centers could extend their historical (hist-ext) simulations if they choose to. This would entail minimum cost.

To clarify, if they're "historical-ext" simulations then they're not DECK simulations anyway, right?

[durack1]

we put those updates under a mip_era of "CMIP7Plus"

For the forcing data and input4MIPs ESGF project, this makes sense to me. I'm not sure it makes sense to others. For example, would Steve be happy for his "provisional" data to be marked CMIP7Plus? As a single vote, I'd be more than happy for my PCMDI-AMIP-2-x-y data to be marked CMIP7Plus if that makes comms cleaner.

I would note that however we identify these forcings, they are likely to be used in simulations published to the CMIP7 ESGF project, so I am just noting that nuance.

[znichollscr]

For example, would Steve be happy for his "provisional" data to be marked CMIP7Plus?

If we put this under CMIP7, it'll be super confusing (are we saying that this should be used for the DECK or not?). Maybe the other way through it would be to put it under mip_era="CMIP7" but target_mip="SomeNewMIPOnProvisionalData". Either way, it wouldn't be under mip_era="CMIP7" and target_mip="CMIP" so we can differentiate.