SCIENCE OF SEASONAL CLIMATE PREDICTION

Evaluating the skill of seasonal forecasts: Methods and problems
by Robert Fawcett, National Climate Centre, Bureau of Meteorology

Dr Robert Fawcett is a senior meteorologist in the National Climate Centre, Bureau of Meteorology, Melbourne. His duties at NCC have included operational climate monitoring/prediction, client support and systems maintenance/development. He has recently become an Associate Editor of the Australian Meteorological Magazine, and is a co-author of a report on the operational verification of the Bureau’s seasonal outlook service.

This presentation will discuss some of the issues and difficulties surrounding the evaluation of seasonal outlooks. It will cover validation (hindcast) versus verification (forecast) issues, selection of appropriate scoring techniques, the importance of cross-validation in hindcast skill assessment, and matters specific to the new coupled general circulation models (CGCMs). The properties and relative merits of different forecast scoring techniques can be investigated by applying them to simple theoretical models, an approach which the National Climate Centre has found useful. Results arising from both analytical calculations and Monte Carlo simulations will be presented.