repeats through the length of the run. Unlike its predecessor HadCM2 there is no need for flux correction—the model climate remains stable and does not significantly drift. The lack of flux correction is cited by the IPCC as one of the advances in modelling since the IPCC Second Assessment Report. The ocean model incorporates a thermodynamic-dynamic sea ice model with primitive (ocean drift) dynamics. Slab model (HadSM3) The atmospheric model may be run coupled to a simpler "slab ocean" rather than the full dynamic ocean. This is faster (and requires less memory) than the full model, but lacks dynamical feedbacks from the ocean, which are incorporated into the full coupled ocean–atmosphere models used to make projections of climate change out to 2100. The slab model needs a calibration phase in which the ocean temperatures are held to climatology while it calculates the "flux correction", i.e., extra ocean-atmosphere fluxes needed to keep the model ocean in balance (the model ocean does not include currents; these fluxes to some extent replace the heat that would be transported by the missing currents). After this calibration period the model may be run in climate mode. See also Climateprediction.net Attribution of recent climate change Earth Simulator NCAR EdGCM References External links Met Office climate prediction model: HadCM3 Access to the HadCM3 (HCCPR) experiments, IPCC Data Distribution Centre Met Office Numerical climate and weather models