Developing smoke dispersion modelling capabilities in NZ: the wilding burn project
Tara Strand, Scion
Marwan Katurji, UC
This project brings together Scion’s Rural Fire Research Team (Scion) and University of Canterbury, Geography Department (Geography) in partnership to develop wildfire smoke modelling capability and decision support tools in NZ. Geography will be linked into international smoke modelling research and end-user groups through Scion’s membership in the BlueSky Smoke Modelling Framework (BlueSky Framework) consortium. The BlueSky Framework is a US-developed modelling framework used to predict wildfire and prescribed fire smoke emissions, concentrations and dispersion. The University of Canterbury’s UC HPC supercomputer will be used to generate smoke model predictions for the wilding research burns. UC HPC allows for easy linking of Geography’s fine scale WRF model output to the BlueSky Framework to generate smoke dispersion concentrations.
Wildings are trees that have spread outside their plantation blocks and are considered weeds. The various differences in wilding fuel loads, age, density, treated (to kill), and untreated is somewhat unique to New Zealand. Fire and smoke behaviour and other risk assessment tools require the addition of these fuel types to better inform fire management strategies.
The wilding burn project will collect data to evaluate internationally developed fuel, fire behaviour, and smoke modelling tools for the New Zealand wilding scenario. Current models, in use in NZ, do not adequately describe the wilding conifer fuel loading and fire behaviour. The newly developed fuel models from North America for insect killed forests may prove to be useful for treated wildings, however we do not know which models are relevant for NZ. The research burn will collect data so that fire and smoke behaviour models can be tested and modified for the NZ environment.
Modelling smoke from NZ fires is becoming important due to complaints of recent visibility impacts in tourist locations (Wanaka, Queenstown, etc.) and the impacts smoke can have on human health, transportation corridors (airports, etc.), and fire operations. This burn provides the opportunity to observe smoke plume characteristics and test the BlueSky Framework in NZ. The smoke dispersion goals of the burn are to:
- Link the BlueSky Framework with University of Canterbury’s fine scale WRF meteorological prediction to test this joint capability
- Test the BlueSky Framework for its capability to simulate smoke production and dispersion in the NZ fire environment;
- Measure the heat and turbulence permutations generated by the fire front in the treated fuels at various heights ranging from near ground to 75 m along with the vertical wind and temperature profiles; and
- Incrementally measure the smoke plume top to (a) evaluate BlueSky model predictions and (b) relate plume top height to turbulence and temperature perturbations measured near the ground.
International and National Links
Variants of the BlueSky Framework, developed by the US Forest Service, are in use in the USA, Canada, South Korea, and Portugal to predict smoke impacts from wild and prescribed fires, and Australia is currently testing it for prescription burn planning. In partnership with Geography, Scion, a member of the BlueSky Consortium, is testing its use in NZ with the eventual possibility of NZ Rural Fire Authority adopting its output for wildfire operations.
The goal of the wilding burn research is to show the proof of concept of good smoke forecasts when Geography’s fine-scale WRF metrological output is used as input into the BlueSky Framework. This project establishes the foundation of a long-term joint approach to develop smoke dispersion end-user decision support systems tailored to the NZ fire environment.
The Department of Geography is currently supervising a PhD student working on fire-atmospheric interaction dynamics. The collaboration between Scion, and Geography and the support of UC HPC is identified as a key advantage for the success of this PhD research. The PhD research has already an existing UC HPC account on a separate project but we would like to stress the importance of the research connectivity of these two projects. The study of small-scale fire-atmospheric interaction and its micrometeorology will influence the short and long term dispersion of fire smoke.