The UKESM1 model participated in the 6th Coupled Model Intercomparison Project (CMIP6), delivering an ensemble of Earth system projections, for the coming century and beyond, for use by UK researchers and government.

Model output data from UKESM1 and HadGEM3-GC3.1 has been published to the international research community through the Earth System Grid Federation (ESGF). Documentation and first analysis of these models is being published in a special issue of JAMES.

A summary of the data available and to be published is in the table below. To download the data, go to the CEDA ESGF node. To search for the UK models specifically, you will need to select the corresponding “Source ID”. These are abbreviations of the full model names to comply with CMIP technical requirements:

Model Resolution CMIP Source ID DECK simulations
UKESM1.0 N96ORCA1 UKESM1-0-LL Published
HadGEM3-GC3.1 N96ORCA1 HadGEM3-GC31-LL Published
HadGEM3-GC3.1 N216ORCA025 HadGEM3-GC31-MM Completed, to be published
HadGEM3-GC3.1 N512ORCA025 HadGEM3-GC31-HM None, see note 2
HadGEM3-GC3.1 N96ORCA025 HadGEM3-GC31-LM None, see note 2

Table notes:

  1. LL, HM etc are abbreviations for the model resolution (Low, Medium, High). The first letter indicates the atmosphere resolution; the second indicates the ocean resolution.
  2. DECK is a set of core experiments for CMIP, consisting of: piControl, abrupt4xCO2, 1pctCO2, AMIP. The N512ORCA025 and N96ORCA025 resolutions of HadGEM3-GC3.1 are used solely for HighResMIP; there are no DECK experiments for these configurations.

The data published so far consists of monthly and daily frequency data for a high-priority subset of variables. More variables and frequencies will follow.

Data published (a subset of monthly and daily frequency variables):

  • UKESM1.0-N96ORCA1 Historical: 9 ensemble members
  • UKESM1.0-N96ORCA1 ScenarioMIP: Tier 1 and Tier 2 scenarios; 5 ensemble members
  • UKESM1.0-N96ORCA1: Some experiments for AerChemMIP, C4MIP, LUMIP
  • HadGEM3-GC3.1-N96ORCA1 DECK and historical
  • HadGEM3-GC3.1-(various resolutions): HighResMIP
  • HadGEM3-GC3.1-N96ORCA1: Some experiments for RFMIP, DAMIP

Available soon (a subset of monthly and daily frequency variables):

  • HadGEM3-GC3.1-N216ORCA025 DECK and historical
  • UKESM1.0-N96ORCA1 Historical: 7 more ensemble members
  • Additional variables for all of the experiments above
  • Additional experiments for the MIPs above
  • UKESM1.0-N96ORCA1: GeoMIP
  • HadGEM3-GC3.1-N96ORCA1: CFMIP

Technical documentation:

Background to CMIP6

As modeling capability has advanced, the need to quantitatively evaluate Earth System Models (ESMs) has also grown. To address this, Working Group on Coupled Modeling (WGCM) of the World Climate Research Programme (WCRP) has initiated a series of Coupled Model Intercomparison Projects (CMIP). In preparation for the IPCC Sixth Assessment, the CMIP Phase 6, CMIP6, was launched. A brief summary can be found in the following overview presentation (CMIP6FinalDesign_GMD_160603.pdf).

The organization of CMIP6 is more distributed than in previous rounds. It contains twenty individual Model Intercomparison Projects (MIPs), each focused on a specific area of Earth system science. In addition, there is a set of fundamental (or DECK) experiments which will be run for each model in order to characterize its performance, and provide a reference point for the various MIP experiments. See the World Climate Research Programme website for more details on CMIP6 and the underlying MIPs that constitute CMIP6.

The UK contribution to CMIP6

CMIP6 will be an important application of UKESM models. CMIP6 aims to improve our understanding of, and ability to simulate, key climate phenomena and future climate change using a coordinated multi-model approach. In CMIP6, UKESM1 and other climate models from around the world will be integrated using a common set of experiment protocols to address a range of key science questions.

The UK contribution to CMIP6 will come from the Met Office, NERC centres and UK universities and is being coordinated through a number of thematic groups (see the article in Newsletter No 2:UK Plans for CMIP6for more information) currently working on tasks such as:

  • ensuring model components meet the technical requirements for CMIP6;
  • providing technical support for model runs, data conversion and delivery;
  • sharing good practice (including experiment setup) across MIPs and coordinating MIP numerical experiments.

More detailed information about CMIP6 workshops is available on the Met Office website (

Institutions in other countries are also using the UK models to contribute to CMIP6 – for example, the National Institute of Meteorological Science / Korean Meteorological Administration (NIMS-KMA) and New Zealand’s National Institute of Weather and Atmospheric Research (NIWA) are performing selected simulations from the historical, ScenarioMIP and AerChemMIP experiments using UKESM1.  The results from these simulations will be made available on ESGF alongside those run by UK institutions using the same model. 

CMIP6 UK Seminars

CMIP6 Analysis online seminars were held on 20-21 April 2020. The seminars brought together scientists working on the analysis of CMIP6 simulations to present and discuss their work. Further information: CMIP6 Analysis Online Seminars

For more information about the UK CMIP6 workshop held on 27 February 2019 in Oxford, please visit