@article {bnh-7900, title = {Coupled fire-atmosphere modelling {\textendash} final project report}, number = {650}, year = {2021}, month = {03/2021}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

This project aims to improve understanding of fire and atmosphere interactions and feedback processes through running the coupled fire-atmosphere model ACCESS-Fire.

Project deliverables include: preparation of meteorological and simulation case studies of significant fire events as publications; installation and testing of the ACCESS-Fire coupled model on the National Computing Infrastructure (NCI); and preparation of training material to support operational implementation of research findings.

The project started in March 2016, and progress over the past four years has delivered across several activities:

The project has demonstrably achieved the objective of building and sharing national capability in fire research and has provided fire and meteorology expertise during high impact events in support of end-users inside their operational centers.\  That outcome is not a specific project deliverable and is to some degree intangible, so not as easily measured as outcomes such as publications.\  However, it successfully realises the CRC objective of building collaborations and trusted partnerships and strengthening national capability. The operational support capability is recognised and valued across fire and land management agencies and in the Bureau.

To complete the project we will finalise publication of the draft papers to ensure that our key findings are documented in the scientific literature; this will expand the international body of knowledge from coupled modelling studies.\ 

We are pleased to bring the project to completion and are gratified that along the way we have shared a valuable legacy of knowledge on fire and atmosphere interactions.\  We have also delivered an important capability in ACCESS-Fire that can provide ongoing benefit to the field of meteorology and fire prediction and to the Australian community into the future.

In the coming months we will continue our conversations with partners and end-users to establish plans for future use and development of ACCESS-Fire as the BNHCRC transitions to the new Disaster Resilience Research Institute.\ \  ACCESS-Fire is an important research tool and has the potential to be a critical operational tool. It will assist in informing fire management decisions as we face increasingly hazardous scenarios in a changing climate.

}, keywords = {coupled, fire-atmosphere, modelling}, issn = {650}, author = {Mika Peace and Jeffrey Kepert and Harvey Ye and Jesse Greenslade} } @article {bnh-8253, title = {Coupled fire-atmosphere simulations of five Black Summer fires using the ACCESS-Fire model - Black Summer final report}, number = {705}, year = {2021}, month = {05/2021}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

Context

This research builds on previous work completed during the Coupled fire-atmosphere modelling ACCESS-Fire project, by conducting case studies of five major bushfires that occurred across Australia during the 2019-20 summer. The previous work provided valuable insights into the drivers of periods of extreme fire behaviour associated with the Waroona fire in WA, and the Sir Ivan fire in NSW.

The main objectives of this project are: to investigate the meteorological drivers of extreme fire behaviour at five further fire events; to further test the reliability and stability of the model in different environments across Australia; and to support and share learnings from the events of the 2019-20 summer with partner agencies.

The fire events nominated by state jurisdictions for investigation were: Badja Forest (New South Wales), Stanthorpe (Queensland), Green Valley Talmalmo/Corryong\ (NSW/Victoria), Kangaroo Island (South Australia); and Yanchep (Western Australia).

The case studies show that the local context for each fire is important. Each of the fires posed significant challenges in different ways. In the heavily forested areas of NSW and Victoria, the sheer size, intensity, and duration of the fires were distinctive. At other fires, the proximity of local communities and infrastructure posed serious challenges. All fires were active in the overnight period when conventional fire danger indices typically suggest a decrease in fire activity.

The marine boundary layer, local coastal effects and topography combined to generate complex wind flows that influenced the progression of the Kangaroo Island fire. We also studied the way in which the sea breeze circulation interacted with the Yanchep fire, and examined the impact of a prescribed burn on the rate and direction of spread of the Stanthorpe fire under extreme fire weather conditions.

This project has explored gaps in knowledge and understanding of the processes at play during these unusual events by using the Bureau{\textquoteright}s ACCESS-Fire model to examine the local three-dimensional interactions between the fires and the atmosphere. The learnings from this project may be applied to shape future fire weather products and services.

Method

Based on discussions with our partners in fire agencies, together with documents (including photographs and video) and information on fire spread, fuel types and fuel moisture and atypical fire behaviour, we have run a series of simulations and prepared case study chapters for each of the five fires.

The ACCESS-Fire model was initialised using information provided by fire agencies on ignition location or fire line perimeter and fuel type and availability. Several simulations were conducted for each of the fires, with a focus on different time periods of interest and using updated fire polygon boundaries based on available line scan imagery.

The model configuration does not permit the simulations to account for suppression activities by fire agencies, changes in fuel types on the urban interface, or the impact of roads or other fire breaks in reducing the rate of spread of the fire. Another limitation is that the simulations are a single realisation, when in reality, consideration of forecast uncertainty (for example through running an ensemble scheme) would capture a range of potential outcomes.\ 

Learnings from the case studies reinforce and refine some previous learnings from historical fire events and uncover some new insights into the processes driving the periods of unusual fire behaviour that were observed during the 2019/20 season.

Key findings

The case study analyses have provided valuable insights into meteorological aspects of observed extreme fire behaviour during the 2019/20 summer. Key findings for each of the five case studies are included in the individual chapters for each fire and a synthesis is provided here.\ 

The ACCESS-Fire simulations run at 300 m spatial resolution show that some of the most dangerous effects of the fires, in particular damaging and destructive winds, are fire driven and therefore very localised at a much finer scale than current fire weather products.

The depth, elevation and structure of low-level jets over topography was a critical driver of overnight fire activity.\  Given that these jets are driven by larger scale processes (typically synoptic scale), there is an opportunity to develop new tools based on numerical weather prediction output that highlight the location and intensity of these features. Such tools would provide additional information for meteorologists and FBANs on the strength and height of representative winds for input to two-dimensional fire spread models and could be used to alert fire managers to the risk of atypical fire spread in the overnight period.

A key theme that emerged from the case studies and discussions with stakeholders was the consistent occurrence of heatwaves and their influence on boundary layer structure overnight and on inhibiting fuel moisture recovery during the overnight period. Further research quantifying the effects of overnight heatwaves is required to appropriately plan for the increased risk to communities and fire crews in a changing climate, as the frequency of elevated overnight temperatures has increased over the last few decades and is projected to increase further (along with other factors influencing fire activity).\ \ 

Deep moist pyroconvection producing pyrocumulus (pyroCu) or pyrocumulonimbus (pyroCb) clouds was a feature of the 2019-20 fire season and a record number of sustained outbreaks of pyroCbs occurred.\  However, the five fires examined here were not all associated with pyroCb, highlighting that it is not the sole weather phenomenon associated with extreme fire behaviour. In particular, no lightning was detected within the Green Valley Talmalmo fire (that subsequently became the Corryong fire when it burned into Victoria) as it burned through Green Valley, which shows that dangerous tornado-strength fire-generated winds can occur without pyroCb.

The simulations produced fire-generated extreme winds associated with both rotation and straight-line flow, which present a serious hazard. ACCESS-Fire simulated rotating winds in the updraft of the Green Valley Talmalmo/Corryong fire. More work is required to understand the mechanisms for these, they are likely related to the high intensity of the fire, coupled with topographic influences.

Spot fires were an important component in the observed rate of spread, particularly in the forest fires overnight. The extremely dry, drought-affected fuel beds meant that the ignition efficiency of spot fires was enhanced compared to an average season. Inclusion of a spotting parameterisation in ACCESS-Fire would accelerate the forwards fire spread and improve validation of the simulated fire perimeters.\ 

Coastal processes were evident in the simulations of the Kangaroo Island and Yanchep fires. Localised wind effects in the simulations showed interactions between the fire and maritime airmass including sea breeze circulations can modify the updrafts associated with the fire as well as produce rapid transitions in fire intensity around a fire perimeter. Cooler moister air associated with a maritime airmass may not necessarily reduce fire intensity, depending on its depth and penetration inland.

Utilisation - where to from here?

The high level of engagement in this work from a range of stakeholders has demonstrated the value of this research and the appetite for operational application.\ 

The learnings from this work should be incorporated into training packages tailored for fire meteorologists and FBANs that describe characteristics of the local meteorological environment favourable for extreme fire behaviour. Such training will complement other current research and training on fire behaviour aspects such as spotting and potential for pyroCb.

This work, which has been conducted in close collaboration with partners in fire agencies, has demonstrated that a comprehensive understanding of the mechanisms driving fire behaviour requires a multidisciplinary approach. Similarly, the successful application of fire behaviour and meteorology knowledge in operations requires locally connected specialised expertise, combined with tailored modelling tools to inform objective, evidence-based decisions.

The insights gathered from these five case studies have further demonstrated the value of this high resolution coupled modelling approach. In order to progress ACCESS-Fire to an effective operational tool, more robust testing of the model is required, in addition to the more subjective assessments that have been made through the case study work. This would include technical testing, additional sensitivity testing and routine verification.

This project has demonstrated that the Bureau{\textquoteright}s technology and simulation capability, scientific expertise and established relationships with fire agencies can meet the Australian community{\textquoteright}s need to understand the drivers of fire behaviour during the 2019-20 fire season. In doing so, we have further developed and validated our modelling systems and made progress towards their future operational use.

}, keywords = {ACCESS-Fire, black summer, coupled, fire-atmosphere, simulations}, issn = {705}, author = {Mika Peace and Barry Hanstrum and Jesse Greenslade and Dragana Zovko-Rajak and Abhik Santra and Jeffrey Kepert and Paul Fox-Hughes and Harvey Ye and Tasfia Shermin and Jeffrey Jones} } @article {bnh-7509, title = {Coupled fire-atmosphere modelling: ACCESS-Fire {\textendash} annual report 2019-2020}, number = {630}, year = {2020}, month = {11/2020}, institution = {Bushfire and Natural Hazards CRC}, address = {MELBOURNE}, abstract = {

This project aims to improve understanding of fire and atmosphere interactions and feedback processes through running the coupled fire-atmosphere model ACCESS-Fire.

Project deliverables include: preparation of meteorological and simulation case studies of significant fire events; installation and testing of the ACCESS-Fire coupled model on the National Computing Infrastructure (NCI) and preparation of training material to support operational implementation of research findings.

The project started in March 2016, and progress over the past four years has been on several aspects:

  1. ACCESS-Fire has been installed on NCI and substantial investment has been made in testing and developing the model
  2. A meteorological case study of the Waroona fire has been published, which generated outreach activities across numerous agencies and jurisdictions.
  3. ACCESS-Fire has been run on two fires: the Waroona fire in WA and the Sir Ivan fire in NSW. A draft of the results of the Waroona simulations has been prepared and analysis and manuscript outline of the Sir Ivan simulations is well underway.
  4. Operational support was requested by fire agencies and the Bureau during high-impact events during the 2019-20 fire season. Support was provided in CFS and SES in SA, RFS in NSW and QFES in QLD during the protracted fire campaigns.
  5. A draft of the paper {\textquoteleft}Lessons learned from coupled fire-atmosphere research and implications for operational fire modelling{\textquoteright} has been prepared.

The project has continued to participate strongly in outreach activities, including media engagement through extended radio interviews and collaboration on print and online news articles.\  Conference presentations, high level training presentations and panel participation on topics including fire science, High Performance Computing, STEM careers and Women in Leadership have been attended.

The project has demonstrably achieved the objective of building and sharing national capability in fire research and has repeatedly applied that knowledge in critical focus during high impact events in support of end-users inside their operational centers.\  That outcome is not a specific project deliverable and is to some degree intangible, so not as easily measured as outcomes such as publications. \ However, it demonstrates successful realization of the CRC objective of building collaborations and trusted partnerships and strengthening national capability. The capability is recognized and valued across fire and land management agencies and in the Bureau; value that is evidenced by the repeated requests to provide high-level fire and meteorological interpretation inside operations.\ 

We therefore thank BNHCRC for their understanding in allowing flexible deadlines and repeatedly negotiating project timelines and deliverables, as this flexibility to shifting priorities has enabled the project team to provide operational support when it was needed.

Our focus for the remainder of the project is to complete advanced drafts of the papers to ensure that our key findings are documented in the scientific literature and expand the body of knowledge from coupled modelling studies. \ We will also share the results with a range of audiences through three online presentations and recordings during which we intend to develop presenting experience in more junior members of the project team.

These objectives may be challenging, due to the need to work from home during the Coronavirus pandemic and the need to be flexible with plans.

We are confident that we will bring the project to completion and are gratified that along the way we have shared a valuable legacy of knowledge, analysis techniques and software that can benefit the field of meteorology and fire prediction and the Australian community into the future.

}, keywords = {ACCESS-Fire, coupled, fire-atmosphere, modelling}, issn = {630}, author = {Mika Peace and Jeffrey Kepert and Harvey Ye and Jesse Greenslade} } @conference {bnh-6410, title = {ACCESS-Fire: coupled fire-atmosphere modelling}, booktitle = {Bushfire and Natural Hazards CRC Research Day AFAC19}, year = {2019}, month = {12/2019}, address = {Melbourne}, abstract = {

Coupled models are a class of fire prediction models that integrate a fire component with an atmospheric component, to examine how the energy released by a fire modifies the surrounding atmosphere. Coupled models can resolve complex interactions between the fire, topography and atmosphere, which subsequently manifest on fire behaviour. Results from simulations promote understanding of the driving processes in dynamic fire events. This can inform development of predictive tools that may be used to anticipate extreme fire behaviour and mitigate against the impacts of significant fires.

Globally, several coupled models have been developed; mostly by meteorological institutions for application in a research capacity. They can be broadly separated as taking either physical or empirical modelling approaches. We are running ACCESS-Fire; an empirical coupled model. It links the research version of the Australian Community Climate and Earth System Simulator (ACCESS) Numerical Weather Prediction (NWP) to a set of empirically derived fire spread equations. In this presentation we will describe the coupled fire-atmosphere model ACCESS Fire and report on progress on simulations of recent significant fire events.

In Australia and overseas, the imperative for accurate, flexible and timely predictions for prescribed (fuel reduction) burns and bushfires will only increase. Incorporating complex, dynamical meteorological fields is a critical component in building fire prediction systems that can resolve some of the most destructive elements of fire behaviour. Although coupled fire-atmosphere models are currently limited in producing timely operational output due to computational requirements, these restrictions will diminish as technology capabilities continue to increase.

}, keywords = {coupled models, Fire behaviour, fire-atmosphere, Forecasting, modelling}, url = {https://knowledge.aidr.org.au/resources/australian-journal-of-emergency-management-monograph-series/}, author = {Mika Peace and Jeffrey Kepert and Harvey Ye} }