NBIC-ACS Stage 2 Grass Fire Danger Index - projected scenario, 20% and 10% annual exceedance probabilities

Grass Fire Danger Index (GFDI) is a fire weather potential index that describes how current weather conditions and the proportion of dry dead grass could support a fire in grassy areas. GFDI Mark 4 (MK4) calculations are based on McArthur, A.G. (1966) and McArthur, A.G. (1973) and are dependent on air temperature, relative humidity, wind speed and grass curing. GFDI MK4 was originally implemented as a circular slide rule that constrained the returned index between 0 and 100. The data provided here is unbounded.
Here we provide predicted upper-bound GFDI values across the Australian landscape, defined for a set of annual exceedance probabilities (AEP) modelled using extreme values analysis on more than 43 years of daily data. The GFDI potential rasters represent reasonable worst case extreme conditions. Specifically, the rasters represent the GFDI potential for given AEPs of 20%, 10%, 5%, 2% and 1%. These GFDI AEPs are based on the projected weather timeseries developed by NBIC using the historical regional weather reanalysis dataset BARRA-R2 [1], and CMIP6-CCAM Regional Climate Models (RCM) [2].
The Regional Climate Models (RCM) considered are:
• ACCESS ESM 1.5
• EC-Earth 3
• CMCC ESM2
• CNRM ESM 2.1
• NCAR CESM2
• NorESM2 MM
The future climate change scenarios considered are:
• Shared Socioeconomic Pathway (SSP) SSP 1-26: Sustainability
• SSP 3-70: Regional Rivalry
• SSP 3-70: Regional Rivalry, using wind speed from the baseline scenario
The combination of RCMs and future climate change scenarios results in 18 different projected GFDI potential datasets.