Models used in CPDN, University of Oxford

The information below summarises the various types of climate model used by CPDN (climateprediction.net), including some that are planned for future release.

Fully Coupled Global Models

HadCM3

This was the standard coupled model of the Met Office until a few years ago, and is still actively used for climate change research. A future release of this model is planned by CPDN. Read more about this model on the Met Office website.

• Atmosphere: 2.5 x 3.75 degrees lat-lon resolution, 19 vertical levels (known as N48; comparable resolution to ~T42)., 30 mins timestep for dynamics, 3 hours for radiative transfer.
• Ocean: 1.25 x 1.25 degrees lat-lon resolution, 20 vertical levels, 1 hour timestep.

Sulphur and carbon cycles, dynamic vegetation etc. are optional.

HadCM3N

This is another version of HadCM3 which runs for 40 years and is not flux-adjusted. It is used for the RAPID-CHAAOS and RAPID-RAPIT experiments.

HadCM3S

This is another variation of the HadCM3 coupled ocean-atmosphere model. This version of the model is configured for short experiments of a few years length. Additionally, volcanic aerosol is now specified on each latitudinal row of the model individually, and the model also contains multiple calls to the radiation code each time step in order to diagnose the radiative forcing of certain atmospheric constituents.

It is being used for the RAPID-CHAAOS and Solar-Radiation Management Geoengineering experiment.

Atmospheric Models Coupled to a Simple Ocean

HadSM3

HadCM3 but with 1 layer thermodynamic ocean (slab ocean). The CPDN Slab experiment, Sulphur cycle experiment, and mid-Holocene experiments all use this model.

• Resolution: 2.5 x 3.75 degrees.

Atmosphere-only Models

HadAM3

Atmospheric component of HadCM3 with prescribed sea surface temperature. Never used by CPDN as a stand-alone model at the standard resolution of 2.5 x 3.75 degrees.

HadAM3-N144

HadAM3, but at N144 resolution (0.83 x 1.25 degrees resolution, 30 levels) with 10 minutes timestep for dynamics, used for the attribution experiment.

HadAM3P

As HadAM3, but N96 resolution, (1.25 x 1.875 degrees resolution, 19 levels) with 15 minutes timestep for dynamics and improved physics. This has been used for the storm-tracking experiment and was used for the Validation and Attribution experiment.

It is the standard driving model for all Weather@Home experiments. For each regional experiment, a new version of this model is made, focusing on the region in question. These are denoted by the region’s acronym at the end of the model name:

• Europe: hadam3p_eu
• Australia & New Zealand: hadam3p_anz
• Pacific North West: hadam3p_pnw
• Africa: hadam3p_afr

HadAM3PM2

This is the same as HadAM3P but has a better land-surface scheme called MOSES2 and an interactive vegetation scheme called TRIFFID.

This model is used for the HYDRA experiment.

HadRM3P

A high-resolution, regional configuration of HadAM3 with improved physics. This is the regional model used in PRECIS experiments by the Met Office and in all Weather@Home experiments.

It has 0.44 x 0.44 degrees resolution with a rotated pole to achieve approx. 50 km x 50 km resolution on 19 levels (used for the EU region, South Asia, planned for East Asia). Also used is a double resolution variant at 0.22 x 0.22 degrees (Western US, planned for EU and Africa).

HadRM3-TRIFFID

This is a version of HadRM3P being used in the FMEC project, with an interactive vegetation scheme called TRIFFID which will specifically help look at the interaction between climate change and forests.

Hybrid models

PRECIS

HadRM3P, driven by a global model such as HadCM3 or HadAM3P. CPDN uses a HadAM3P driven HadRM3P for the Weather@Home experiment and earlier regional experiments.