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The Australian Google Earth Engine Burnt Area Map (AUS GEEBAM) is a rapid, national approach to fire severity mapping. |
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The Australian Google Earth Engine Burnt Area Map (AUS GEEBAM) is a rapid, national approach to fire severity mapping. |
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[[114.19743217841,-43.4543848975035],[153.563404553823,-10.5799980903825]] |
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New South Wales Department of Planning, Industry and Environment. |
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thumbnail/thumbnail.png |
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["Data","Service","Map Service","ArcGIS Server"] |
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The Australian Google Earth Engine Burnt Area Map (AUS GEEBAM) is a rapid, national approach to fire severity mapping. It has been developed rapidly to support the immediate needs of the Department of Agriculture, Water and the Environment (DAWE) in: a) quantifying the potential impacts of the 2019-20 bushfires on wildlife, plants and ecological communities, and b) identifying appropriate response and recovery actions.
AUS GEEBAM Fire Severity uses Sentinel 2A satellite imagery from before and after fire to estimate the severity of burn within each 40m grid cell. Fire severity is defined as a metric of the loss or change in organic matter caused by fire.
The extent of the 2019-2020 fires was derived from the National Indicative Aggregated Fire Extent Dataset (NIAFED). NIAFED was sourced from the national Emergency Management Spatial Information Network Australia (EMSINA) data service, which is the official fire extent currently used by the Commonwealth and adds supplementary data from other sources to form a cumulative national view of fire extent.
AUS GEEBAM relies on a vegetation index (Relativised Normalized Burnt Ratio, RNBR) that is calculated for burnt areas and adjacent unburnt areas, before and after the fire season. The result is a map of four fire severity classes that represent how severely vegetation was burnt during the 2019-2020 fires.
To determine a reference unburnt condition, the NIAFED extent was buffered by 2km. For each NVIS broad vegetation type, in each IBRA bioregion a reference unburnt RNBR class was determined. That value was available to calculate a standardised offset or a reference unburnt value.
Each IBRA bioregion was systematically assessed to correct for obvious errors. For example, the Very High severity class could be adjusted down by one RNBR Value for a fire where its extent extended into an area of lower severity. Conversely, there were areas of shrublands that had clearly burnt at Very High severity where all of the biomass is likely to have been consumed but low pre-fire biomass had given it a lower RNBR Value.
Each pixel of AUS GEEBAM contains the raw RNBR Value, the RNBR Class and the GEEBAM Value. This allows an end user to observe which values have been adjusted during the calibration away from the default global RNBR Value and allows for some transparency in the process.
Overview of GEEBAM values and their classes:
1 - No data: No data indicates areas outside NIAFED or NVIS categories that do not represent native vegetation (e.g. cleared land, water).
2 - Unburnt: Little or no change observed between pre-fire and post-fire imagery.
3 - Low and Moderate: Some change or moderate change detected when compared to reference unburnt areas outside the NIAFED extent.
4 - High: Vegetation is mostly scorched.
5 - Very high: Vegetation is clearly consumed. |
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| catalogPath:
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| title:
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AUS GEEBAM Fire Severity |
| type:
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Map Service |
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| tags:
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["fire severity"] |
| culture:
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en-AU |
| name:
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AUS_GEEBAM_Fire_Severity |
| guid:
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785A2B38-6F6F-4BFE-A6C6-42B35B589810 |
| spatialReference:
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GCS_WGS_1984 |