On the Application of Regional Models to Climate Change Research
John McGregor
Common Wealth and Industrial Research Organization (CSIRO Atmospheric Research)
Melbourne, Australia
Because of computer limitations, global climate models have been restricted until recently to fairly coarse resolution. Consequently they have had difficulty in capturing regional features of climate. In order to obtain more realistic regional detail, an increasing number of groups are now using regional climate models, driven in various ways by a previous GCM simulation. At CSIRO Atmospheric Research, we have for some years been using DARLAM, a one-way-nested limited area model. Recently, we have developed a variable resolution global model formulated on the conformal-cubic grid, as an alternative and, we believe, preferable technique.
The talk will briefly describe the formulations of both models. Simulations will be shown to illustrate the benefits and limitations of the regional modelling approach. For DARLAM, several 140-year simulations have been performed over the Australian region. Recently, both models have been used at the same 60 km resolution and with identical physics for the Regional Model Intercomparison Project (RMIP) - a challenging 18-month simulation for 1997-1998 over a large Asian domain.