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Regional Climate Model (RCM)

A regional climate model (RCM) is a climate model of higher resolution than a global climate model (GCM). It can be nested within a global model to provide more detailed simulations for a particular location. HadRM3 is the RCM used for the UKCP09 scenarios.

In detail

Local climate change is influenced heavily by local topographical features such as mountains. Due to their coarse resolution, small-scale topographical features are not picked up by GCMs. RCMs have a higher resolution than a GCM (~ 25 km) and are influenced by a smaller scale of topographical features. It is much more computationally intensive to run an RCM so they are usually run over a limited area. In the case of UKCP09 this was over Europe.

HadRM3 has been used in UKCP09 to produce 11 runs of regional climate projections with the medium emission scenario (A1B), with data saved on a daily time scale. These 11 runs were used to downscale the larger ensemble of GCM runs.

  • More details about the climate models used in UKCP09 are given in Box 2.1 in the UKCP09 Climate change projections report. A commentary about the strengths and weaknesses of climate models is given in Annex 3.
  • The 11-member RCM data is available to users. It is described in the Reports & guidance section and in Chapter 5 of the UKCP09 Climate change projections report.

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