Implementation of the initial ACCESS numerical weather prediction system

The Australian Community Climate and Earth-System Simulator (ACCESS) is a coupled climate and earth system simulator being developed as a joint initiative of the Bureau of Meteorology and CSIRO in cooperation with the university community in Australia. The main aim of ACCESS is to develop a national approach to climate and weather prediction model development. Planning for ACCESS development commenced in 2005 and significant progress has been made subsequently. ACCESS-based numerical weather prediction (NWP) systems were implemented operationally by the Bureau in September 2009 and were marked by significantly increased forecast skill of close to one day for three-day forecasts over the previously operational systems. The fully-coupled ACCESS earth system model has been assembled and tested, and core runs have been completed and submitted for the Intergovernmental Panel for Climate Change (IPCC) Fifth Assessment Report. Significant progress has been made with ACCESS infrastructure including successful porting to both Solar and Vayu (National Computational Infrastructure (NCI)) machines and development of infrastructure to allow usage by university researchers. This paper provides a description of the NWP component of ACCESS and presents results from detailed verification of the system.