From Unofficial BOINC Wiki
A Slab Model is a Climate Model that uses a form of simplified ocean. For the Slab Models, Climateprediction.net (CPDN) uses a UK Met Office model designated HADSM3 which stands for Hadley Centre (The climate division of the UK Met Office) Slab Model version 3.
The slab can act as a heat source or sink which can to some extent simulate the effect of currents flowing. However, there isn't any real current nor turn-over (vertical motion) in the slab oceans so while a slab model can simulate the climate effects of a steady current it is not really modelling the current and cannot simulate a dynamic change in an ocean current or overturning circulation.
Slab Models are useful for Equilibrium climate model runs. As the ocean is simplified it does not take a long time for the ocean to fully adjust to the new forcings and therefore the climate does not take anywhere near as long to settle down into its final pattern. (Like 20 model years instead of over 200 model years.) You can therefore get a reasonable idea of the overall effect of a forcing like an x% increase in CO2 in a shorter amount of computer time.
Issues relating to the Slab modelling go a long way to explaining "Cold Equator" Runs.
- Boinc Slab Model (HADSM3)
 Also See
- Definitions of model type descriptive words
- Types of Model - Experiment list
- Climateprediction.net Model Parts
- Climateprediction Size Table