Assessment of international seasonal rainfall forecasts for Australia and the benefit of multi-model ensembles for improving reliability

  Available online: https://www.cawcr.gov.au/technical-reports/CTR_039.pdf

In this report we assess forecasts from Predictive Ocean Atmosphere Model for Australia (POAMA) in comparison to international dynamical coupled model forecast systems, which are archived as part of the ENSEMBLES project. We investigate how universal the lack of reliability is in dynamical forecasts of regional rainfall, in order to highlight any potential for improvement of the POAMA system. The systems assessed in this report show that overconfidence and lack of reliability for regional rainfall forecasts is a common problem. Due to the clear need for improved reliability and more accurate seasonal rainfall forecasts for hydrological applications, we have explored the benefit of combining a range of operationally available models into a multi-model ensemble, which can cancel uncorrelated error, increase spread and reduce model error. Our results indicate that there is benefit in adding POAMA version P24 to the operational models from the European Centre for Medium-Range Weather Forecasts (ECMWF), the UK Meteorological Office (UKMO) and Météo France (MF), into an equally weighted multi-model ensemble, to increase the reliability and consistency of accurate regional rainfall forecasts.

Collection(s) and Series:  CAWCR technical report- No. 39

Language(s): English

ISBN (or other code): 978-1-921826-56-6

Tags: Water ; Hydrological forecast ; Modelling ; Precipitation forecasting ; Australia Add tag