Melbourne: When the heavens opened over Townsville bringing massive floods at the beginning of the year, researchers were also inundated with some of the most precise data ever recorded for this kind of event.
That data revealed that over the two weeks from January 25 to February 7, even though no single day was record breaking, enough rain fell over 260 km2 around Townsville to fill 14.4 million Olympic swimming pools or the equivalent of 72 Sydney Harbours. The highest rainfall in any one square kilometer was 2.2m.
This level of accuracy is all thanks to data extracted from Australian weather radar network that has now been compiled by researchers from the ARC Centre of Excellence for Climate Extremes (CLEX) and the Bureau of Meteorology into a 20-year-long precipitation dataset, the Australian Operational Weather Radar Dataset.
“Technology has replaced the simple rain gauge that collected rainfall in a single spot with a network of 50 radar sites that can capture rainfall out to 150km from the radar source,” said Dr Joshua Soderholm who led the construction of the dataset.
“With this dataset we can examine the climatology of extreme events, follow cloud processes, estimate hail size, determine the height of the top of clouds and many more measurements that are invaluable to extreme weather researchers.”
Using this data, the researchers have also even been able to create a three-dimensional animation showing the passage of severe thunderstorms (see above) and a series of large hail events that hit Sydney on December 20, last year. In this 3D-representation it is possible to see how high the hail forms, where it forms and the trajectory from cloud top to the land surface.
They have also produced an animation showing how the rainfall over Townsville steadily accumulated over the two weeks leading to the massive floods, which are estimated to have cost $1bn dollars in stock loses and damage.
“The Bureau of Meteorology’s real time weather radar page is already one of the most visited Australian website pages by the Australian public. But for scientists this new detailed data archive gives us an invaluable historical map of precipitation and its characteristics in Australia,” said co-author of the datatset Professor Christian Jakob from the Monash University Node of CLEX.
“The 20-years of data from the Bureau of Meteorology’s radar network will help researchers understand more about rainfall processes and open many new avenues for research and education.”
To encourage the use of the data, the three partners – Bureau of Meteorology, National Computational Infrastructure and CLEX – have released the complete archive for research and education use. Data from the archive is available on demand through an open access portal hosted on NCI and updated daily.
For scientists wanting to explore the data in the original radar coordinates, ‘volumetric’ data is available. Alternatively, data is also available as on a Cartesian grid for NCI users.