Mobile radar fire plume project Western Australia

Mobile radar offers the promise of providing key decision support for meteorological hazards and evolving fire behaviour in and around fire grounds. In order to test the concept, a high-power mobile dual-polarimetric weather radar has been successfully deployed near several prescribed environmental burns in south-west Western Australia (WA) as part of a collaborative project between Monash University and state and federal agencies. The project aims were to demonstrate the feasibility of deploying a mobile dual polarisation radar near a fire and to capture data that is relevant to nowcasting of hazards and that can contribute to the development of improved tools for fire management.

The science aims of this project were:

• To demonstrate the ability to safely locate and operate the radar in (relatively) close proximity to fires.
• To demonstrate the diagnosis and detection of wind shifts using the ‘clear air scatter’ for nowcasting.
• To demonstrate the detection of ash and embers and discrimination from other airborne particles such as raindrops, using the dual polarisation data.
• To develop strategies for potential operational detection and monitoring of the development of precipitation and smoke/ash plumes.

The cooperative aims of this project were:

• To conduct a multi-agency field research project in south-west WA.
• To hold a multi-agency workshop to discuss the results of the field campaign.
• To provide a learning and development opportunity for field and technical operatives to work with leading scientists.
• To produce a report capturing and summarising the opportunities presented by mobile radar for understanding fire plume processes and ultimately mitigating impacts associated with fires.

It was possible to deploy the radar within a few kilometres of the firegrounds for all the potential cases we examined in south-west Western Australia, including for burns that were surveyed, but not sampled. The data collected clearly demonstrates the ability to measure detailed three-dimensional wind fields in the environment in and around fires and to obtain high-quality observations of smoke/ash plumes with two-minute time resolution and precipitation with a clear separation between precipitation, clouds, clear air and fire ash plumes. This kind of data has clear potential applications for monitoring the changing wind fields around and within the fire. This may permit meteorologists and fire behaviour analysts to make timely decisions to mitigate risk. It can also inform research into developing predictive techniques for processes in fire plumes. The observations clearly showed the ability to observe wind circulations and map the ash plumes. Coupled fire models and predictive methods based on models are reliant on a small number of observations, so additional high-resolution data around fires will be invaluable in improving these methods. Improved predictions will support more accurate and targeted community messaging in a future climate where high-intensity fires are expected to become more frequent and impactful.

Data collected showed that even in these low-intensity fires, the local environmental winds were significantly modified. Further, the radar data shows the circulations within the fire plumes and the potential to detect hazardous winds as they develop.

The project has developed operating procedures and approaches for the safe location and operation of a mobile radar, as well as making recommendations on requirements for robust operational radar deployment practices.