Models used by CPDN

The information below summarises the various types of climate model used by CPDN, including some that are planned for future release. There's some further discussion on the unofficial BOINC wiki.

Fully coupled models

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.

• 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.

HadCM3 with a reduced resolution ocean. This was used for the BBC Climate Change experiment (including the CPDN version) and the Geoengineering experiment. The CPDN version uses two kinds of modified ocean topography, both with no Iceland.

• Atmosphere: same as HadCM3.
• Ocean: 2.5x3.75 degrees, 20 levels, 1 hour timestep.

A fast, coarse resolution variant of HadCM3. This model has been used for the Millennium Experiment.

• Atmosphere: 5.0 x 7.5, 11 levels.
• Ocean: 2.5 x 3.75 degrees, 20 levels, 12 hour timestep, no Iceland.

Atmospheric model coupled to simple ocean

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

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

As HadAM3, but N96 resolution, (1.25 x 1.875 degrees resolution, 19 levels) with 15 minutes timestep for dynamics. This is planned for the storm-tracking experiment. This is used for Validation and attribution experiment and is planned for the storm-tracking experiment.

A high-resolution, regional configuration of HadAM3 with improved physics. This will be used for the regional model in PRECIS.

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. Also used is a double resolution variant at 0.22 x 0.22 degrees.

Hybrid models

HadRM3P, driven by a global model such as HadCM3, HadCM3L or HadAM3P. CPDN uses a HadAM3P driven HadRM3P for the weatherathome experiment and earlier regional experiments.

Acknowledgements: William Ingram; Neil Massey, Myles Allen and Hiro Yamazaki.