Model configuration describes what processes, linkages and feedbacks are included in a climate model.
A climate model simulates the physical processes that operate in some or all of the atmosphere, ocean and land. There are various different model types that can be used to model each of these components, ranging from the simple to the complex. For example, it is possible to model climate using a relatively simple slab ocean model, or a fully dynamic 3-D model. In addition, it is possible to couple sub-models such as ocean, carbon cycle, and sulphur cycle, in an AOGCM. This decision will be made on the basis of the kind of question a modeller wants to investigate or answer, and also available computer power. In UKCP09, there are four different model configurations used, these are HadCM3, HadSM3, HadCM3C, and HadRM3.
For a given model configuration there can be many model variants.
- An overview of how probabilistic projections are created and presented in UKCP09 is described in Box 3 of the UKCP09 Briefing report. More details are provided in Chapter 3 of the UKCP09 Climate change projections report, including an overview of the methodology in Section 3.2.12.
- More details about the climate models used in UKCP09 are given in Box 2.1 in the UKCP09 Climate change projections report. Table 2.1 provides a list of the processes and feedbacks included, and not included, in the UKCP09 probabilistic projections. A commentary about the strengths and weaknesses of climate models is given in Annex 3.