Introducing radar based quantitative precipitation estimates (QPE) in Australia—potential applications and partnerships

The “rainfields” system introduced as part of the radar upgrade project will provide operationally quantitative estimates of rainfall based on the combination of radar and rain gauge observations. The use of rainfall as grid data compared to current practice of point rainfall measurements reliant on a network of rainfall gauges will bring both challenges and potential benefits to the hydrological community which depend on rainfall data for the day-to-day operations as well as longer term planning. The extent of this uptake of this new “type” of rainfall information will be dependent on the adequacy of the coverage in relation to watersheds of interest as well as the relative accuracy of the data itself. The increased spatial resolution is expected to contribute to improved understanding of localised flooding. Already local authorities in Sydney and Melbourne concerned about surcharging of the sewerage system from stormwater have begun to use radar based QPE to carry out activities such as sensitivity analysis. The Brisbane City Council responsible for drainage matters within it's jurisdiction is a potential user wanting to link this data to it's “Floodwise” community flood protection system. In Adelaide, the radar based QPE and the short term forecasts are expected to help warn residents of potential flash flood threat arising from significant orographic forcing influences in the Mt Lofty ranges. The planned upgrade of the radar at Yarrawonga will generate benefits to improved water management, in the area managed by Goulburn-Murray Water which involves around 70% of the State of Victoria's stored water, and where irrigated agriculture is the mainstream industry. It will be a challenge to introduce this relatively new rainfall type that provides much improved resolution and overcomes some of the limitations to point rainfall observations to the hydrological community so that this data is adopted into practice with a full understanding of the benefits as well as it's limitations. This paper will outline the initiatives taken by the Bureau of Meteorology as the provider of this data in establishing the necessary framework and forums to help with this important step in hydrological practice of Australia.