CMIP Phase 6 Plus (CMIP6Plus)

The overall goal of CMIP6Plus is to enable modelling groups to contribute to projects initiated post-CMIP6 but before the CMIP7 infrastructure and experimental design becomes available.   Guides for CMIP6Plus modellers, data managers, and data users are coming soon.  For now, if you cannot find the answer to your question on this page, please submit an FAQ.

The CMIP6 phase is due to be formally closed and is not accepting any new MIPs or experiments. New MIPs must either wait for CMIP7 (register here) or register for CMIP6Plus phase (details below).

Important notice: Participants in CMIP6Plus must ensure that the ESGF publication and storage of their data has sufficient funding.  There is no centrally funded archive for this activity.

On this page:

Accessing CMIP6Plus data

Data for CMIP6Plus can be accessed on ESGF.  It is currently accessible via the following indexed nodes:

  • LLNL
  • Additional nodes will be added to this list as access is confirmed.

Overview of CMIP6Plus

The overview paper on CMIP6Plus organisation will be published as a whitepaper (coming soon). This CMIP6Plus overview paper presents the background and rationale for this interim CMIP phase, providing an overview of changes to the infrastructure from CMIP6. A brief summary can be found below.

Following feedback from the CMIP6 Community survey and issues raised on Github, changes have been made to the Controlled Variables (CVs) infrastructure. These consist of three major elements:

  1. Modifications to the controlled vocabularies, Variable Definitions (MIP Tables) and the tools used to manage them.
  2. Registration and approval process for new variables
  3. Registration procedure for MIPs

Important note: Unlike CMIP6 and  CMIP7, for CMIP6Plus there is no coordinated or managed Data Request. MIPs will need to coordinate the list variables they wish to be contributed by modelling groups independently. 

1. Modifications

The technical information needed to produce data for CMIP6Plus is hosted in two GitHub repositories:

  1. MIP-CMOR-tables; a generic set of MIP tables suitable for use across multiple projects https://github.com/PCMDI/mip-cmor-tables 
  2. CMIP6Plus CVs; activity, experiment, model (source id) details that are project specific: https://github.com/WCRP-CMIP/CMIP6Plus_CVs 

MIP Tables

The separation of MIP tables and Controlled Vocabularies (CVs) is to support the use of generic tables across multiple projects e.g. Input4MIPs, obs4MIPs.

Controlled Vocabularies (CVs)

Minor updates to the CVs have been included and more might be made during the lifetime of CMIP6Plus.  User experiences during CMIP6Plus will inform CMIP7 infrastructure development and suggestions are welcomed via the CMIP6Plus CVs GitHub repository.

Supporting tools

CMOR has been updated. To use these MIP tables and CVs, an update to the CMOR library (the 3.8.0 or later) is necessary.  This is available at: Releases · PCMDI/cmor (github.com)

2. Registration and approval process for new variables

MIPs should attempt to minimise the number of new variables where possible and the storage requirements of any additions, being mindful of the associated carbon footprint. The inclusion of high data volume variables (e.g., those on many levels and/or at high frequency) should be avoided unless there is a compelling scientific justification.

For CMIP7 there is a community consultation process via the Data Request Task Team underway.

For CMIP6Plus, MIPs may propose new variables and these will be agreed in consultation with the WIP.  Inclusion in CMIP6Plus will not automatically result in inclusion of the variable in future CMIP phases.

3. Registration procedure for MIPs

The registration procedure is set out below. It has been aligned with the requirements set out in MIP Best Practice Guidance available here (opens in new tab). 

Stage 1 – Declare and register MIP intention

  1. Determine whether MIP timeline is more in line with CMIP6Plus or CMIP7.
  2. Register MIP (at https://bit.ly/MIP-registration). 

Develop an experimental design paper outlining the details specified in the MIP Best Practice Guidance

Stage 2 – Engage with CMIP/WIP panels

After registration the CMIP IPO will facilitate a two-way engagement with the WIP, and CMIP Panel as relevant. The following areas will be discussed during this process (building on the information provided during registration):

  • MIPs to indicate the level of infrastructure support that is required and is available (support cannot be guaranteed).
  • MIPs to confirm sufficient modelling centre interest.
  • MIPs to confirm availability of data storage at an ESGF node, either by the MIP or through the MIP participating modelling centres and to publish data according to CMIP data standards
  • Consultation with the WIP on experiment definition and coordinate with existing CMIP6/6Plus experiments (e.g., ensure no duplicate names and a clearly defined experimental protocol).
  • MIPs to identify any cross-MIP overlaps and identify any likely experiment co-sponsors (as was done in CMIP6).
  • MIPs to confirm plans for developing any required forcing datasets are sufficient.
  • MIPs to suggest how their science questions may align with CMIP Science Goals and their is wider community interest.

Stage 3 – Complete Technical Registration

This will be conducted through the Github issues interface initially.

  1. Liaise with WIP co-chairs and CMIP IPO to update CVs and MIP Tables including:
    • experiment IDs and descriptions
    • models that plan to deliver data 
    • new approved variables (see Section 2 above)
  2. Await confirmation that ESGF configurations have been updated. Technical registration is then complete.
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