Regional Climate Projections, NARCliM, and small spatial/temporal scale extremes.

The need for higher resolution future climate information to inform the user community is a recognised and growing need. Providing projections of all the climate data required by the large and diverse user community is a great challenge. The NSW/ACT Regional Climate Modelling (NARCliM) project is a dynamical downscaling effort to provide robust high resolution climate projections for south-east Australia. NARCliM creates a regional scale ensemble by downscaling, carefully selected, multiple Global Climate Models (GCMs) with multiple Regional Climate Models (RCMs). Such ensembles allow projections of both the most likely future change and the uncertainty around this most likely outcome for the many variables identified by a series user community workshops. Many human and natural systems are sensitive to extremes on very short time scales (flash floods, wind gusts...) that are not included in the traditional climate projections. NARCliM explicitely records and reports these short time scale extremes and seeks to address the questions: Can the RCMs reproduce observed short time scale extremes? How will these extremes change in the future?