Lessons Learned from Coupled Fire-Atmosphere Research and Implications for Operational Fire Prediction and Meteorological Products Provided by the Bureau of Meteorology to Australian Fire Agencies (original) (raw)
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The coupled fire–atmosphere model consisting of the Weather and Forecasting (WRF) Model coupled with the fire-spread model (SFIRE) module has been used to simulate a bushfire at D’Estrees Bay on Kangaroo Island, South Australia, in December 2007. Initial conditions for the simulations were provided by two global analyses: the GFS operational analysis and ERA-Interim. For each NWP initialization, the simulations were run with and without feedback from the fire to the atmospheric model. The focus of this study was examining how the energy fluxes from the simulated fire modified the local meteorological environment. With feedback enabled, the propagation speed of the sea-breeze frontal line was faster and vertical motion in the frontal zone was enhanced. For one of the initial conditions with feedback on, a vortex developed adjacent to the head fire and remained present for over 5 h of simulation time. The vortex was not present without fire–atmosphere feedback. The results show that t...
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The destructive Sir Ivan Dougherty fire burned 55,000 hectares around 250 km northwest of Sydney in New South Wales on 12 February 2017. Record hot temperatures were recorded in the area during the lead-in days and the fire conditions at the time were described as the ‘worst ever seen in NSW’. The observed weather conditions were hot, dry and very windy ahead of a synoptic frontal wind change during the afternoon. ‘Extreme’ to ‘catastrophic’ fire weather was predicted, and the potential for extreme fire behaviour was identified several days in advance. The Australian coupled fire–atmosphere model ACCESS-Fire has been run to explore the characteristics of the Sir Ivan fire. Several features resulting from fire–atmosphere interaction are produced in the simulations. Simulated heat flux along the fire perimeter shows increased intensity on the northern fire flank in response to gradual backing winds ahead of the main frontal wind change. Temporal and spatial variability in fire activit...
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The Waroona fire burned 69 000 ha south of Perth in January 2016. There were two fatalities and 170 homes were lost. Two evening ember storms were reported and pyrocumulonimbus (pyroCb) cloud developed on consecutive days. The extreme fire behaviour did not reconcile with the near- surface conditions customarily used to assess fire danger. A case study of the fire (Peace et al. 2017) presented the hypothesis that the evening ember storms resulted from interactions between the above-surface wind fields, local topography and the fire plume. The coupled fire–atmosphere model ACCESS-Fire has been run in order to explore this hypothesis and other aspects of the fire activity, including the pyroCb development. ACCESS-Fire incorporates the numerical weather prediction model ACCESS (Australian Community Climate and Earth System Simulator, described by Puri et al. 2013) and a fire spread component. In these simulations, the Dry Eucalypt Forest Fire (Vesta) fire spread model is used. In this ...
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Journal of Advances in Modeling Earth Systems, 2010
Simulating the interaction between fire and atmosphere is critical to the estimation of the rate of spread of the fire. Wildfire's convection (i.e., entire plume) can modify the local meteorology throughout the atmospheric boundary layer and consequently affect the fire propagation speed and behaviour. In this study, we use for the first time the Méso-NH meso-scale numerical model coupled to the point functional ForeFire simplified physical front-tracking wildfire model to investigate the differences introduced by the atmospheric feedback in propagation speed and behaviour. Both numerical models have been developed as research tools for operational models and are currently used to forecast localized extreme events. These models have been selected because they can be run coupled and support decisions in wildfire management in France and Europe. The main originalities of this combination reside in the fact that Méso-NH is run in a Large Eddy Simulation (LES) configuration and that the rate of spread model used in ForeFire provides a physical formulation to take into account the effect of wind and slope. Simulations of typical experimental configurations show that the numerical atmospheric model is able to reproduce plausible convective effects of the heat produced by the fire. Numerical results are comparable to estimated values for fire-induced winds and present behaviour similar to other existing numerical approaches.
The Kangaroo Island bushfires of 2007, A meteorological case study and WRF-fire simulation
Chan, F., Marinova, D. and Anderssen, R.S. (eds) MODSIM2011, 19th International Congress on Modelling and Simulation., 2011
In December 2007, Kangaroo Island was set ablaze by numerous dry lightning strikes. Our research into the event has been conducted in two parts; a case study investigating the interactions between the local meteorology and observed fire behaviour, followed by simulations using the coupled atmosphericfire behaviour model WRF-fire. The findings from the case study highlight the importance of including information on atmospheric instability and spatial variation in meteorological parameters in fire weather forecasts. Our preliminary simulations using WRF-fire have explored the ability of the model to capture phenomena observed in the case study. The case study identified two occurrences of unusual fire behaviour which have been simulated: the first, when a fire located in a local sea breeze front convergence zone produced a spectacular convection column which developed by release of potential atmospheric instability triggered by local lifting; the second, when unprecedented fire behaviour was observed in relatively benign conditions, hypothesised to be due to convective plume entrainment of dry air aloft, enhanced by topographically driven processes and very dry, open structured fuels. The circumstances leading to the unusual fire behaviour(s) illustrate known limitations in the current Australian approach to fire weather forecasting, which neglects temporal and spatial variations, three dimensional atmospheric evolution and any interaction of the fire with the atmosphere. We used the coupled atmosphere-fire model WRF-fire to simulate the fires, with the initial aim of running WRF-fire on an Australian event and subsequently to assess the ability of WRF-fire to simulate the vertical dynamics and fire-atmosphere coupling observed in the case studies.
Coupled Fire–Atmosphere Simulations of the Rocky River Fire Using WRF-SFIRE
Journal of Applied Meteorology and Climatology, 2016
The coupled atmosphere–fire spread model “WRF-SFIRE” has been used to simulate a fire where extreme fire behavior was observed. Tall flames and a dense convective smoke column were features of the fire as it burned rapidly up the Rocky River gully on Kangaroo Island, South Australia. WRF-SFIRE simulations of the event show a number of interesting dynamical processes resulting from fire–atmosphere feedback, including the following: fire spread was sensitive to small changes in mean wind direction; fire perimeter was affected by wind convergence resulting from interactions between the fire, atmosphere, and local topography; and the fire plume mixed high-momentum air from above a strong subsidence inversion. At 1-min intervals, output from the simulations showed fire spread exhibiting fast and slow pulses. These pulses occurred coincident with the passage of mesoscale convective (Rayleigh–Bénard) cells in the planetary boundary layer. Simulations show that feedback between the fire and...
International Journal of Wildland Fire, 1996
Southeastern Australia is particularly vulnerable to wildfires during the spring and summer months, and the threat of devastation is present most years. In January 1994, the most populous city in Australia, Sydney, was ringed by wildfires, some of which penetrated well into suburban areas and there were many other serious fires in coastal areas of New South Wales (NSW). In recent years much research activity in Australia has focussed on the development of high resolution limited area models, for eventual operational prediction of meteorological conditions associated with high levels of wildfire risk. In this study, the period January 7-8, 1994 was chosen for detailed examination, as it was the most critical period during late December 1993/early January 1994 for the greater Sydney area. Routine forecast guidance from the Australian Bureau of…
FireBuster—a web application for high-resolution fire weather modeling
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Chen, Shyh-Chin; Benoit, John; Ritchie, Jack; Zhang, Yunfei; Juang, HannMing Henry; Chen, Ying-Ju; Rolinski, Tom. 2019. FireBuster—a web application for high-resolution fire weather modeling. Gen. Tech. Rep. PSW-GTR-264. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 22 p. Wind and weather in mountainous areas are complex because of the underlying terrain. Typically, regional computer models are needed with sufficiently high resolution to resolve such complex conditions. However, this high-resolution weather information usually becomes available only when the critical time in fighting a severe fire event is long past, thus the advantage of using high-resolution weather models for fire management seems limited. To address this problem, we have developed an experimental system called FireBuster that is designed to streamline and automate many intermediate processes. We are routinely producing forecasts at 5-km resolution over California...