Identification of Rainfall Events and Heavy Rainfall Events From Radar Measurements in Southeastern Australia.

Radar data can be of significant utility in investigating characteristics of rainfall events that cannot be studied with rain gauges alone. The recent establishment of a long‐term, quality‐controlled data set covering most of the radars on the Australian continent enables a deeper characterization of rainfall, including heavy rainfall events. This study develops a methodology to identify and characterize rainfall events from radar data and tests its utility by applying it to the regions surrounding the major cities of Brisbane, Sydney, and Melbourne. The event characteristics studied include rainfall accumulation and intensity, event duration and spatial extent, and the contribution convective areas make to the overall event rainfall. Rainfall events in Brisbane and Sydney are found to be more intense, more convective, and smaller in extent whilst producing larger rainfall accumulations than Melbourne rainfall events. Rainfall event duration and total accumulated rainfall are strongly positively correlated, as are the overall event intensity and the intensity of convective rainfall. The events that produce the largest rainfall accumulations exhibit significant differences from the events that produce the highest rainfall intensities. Overall, the study demonstrates that long‐term radar data sets in Australia provide an invaluable and rich source to study rainfall characteristics in a variety of regions at a high spatial and temporal resolution. Plain Language Summary: Weather radars produce a map of rainfall across a large area. Radars can observe characteristics of rain systems that are difficult to capture with rain gauge networks. A data set containing observations from weather radars in Australia can be used to study the characteristics of rain events. Such characteristics include how long an event lasts, how intense the rain is, how much rain falls overall, how large the event is, and how much of the rain comes from strong ascent (convection). This study develops a method of using radar to find rain events and assess their characteristics, and tests the method using Brisbane, Sydney, and Melbourne radar data. Rain events in Brisbane and Sydney have heavier rain and more rain coming from convective areas, and cover smaller areas, with more rain falling than in events in Melbourne. The longer a rain event is, the more rain is produced. An event having high rain intensity also means it produces intense rain from convective areas. Rain events that produce large rainfall amounts are distinct from those which have very intense rain. This study demonstrates that radar data sets in Australia are very useful for studying rain events. Key Points: Brisbane and Sydney rainfall events are more intense and convective than Melbourne rainfall events, which cover larger areasRainfall events with the highest accumulations and rainfall events with the highest intensities show significant differences in characterLong‐term radar data sets are useful for in‐depth analysis of rainfall and heavy rainfall event characteristics in Australia [ABSTRACT FROM AUTHOR]