Fire Frequency is derived from a time series of burnt area maps (derived from the Advanced Very High Resolution Radiometer (AVHRR)) and provides the average number of fires affecting an area in the given time period. It is the inverse of the fire return interval.

The Advanced Very High Resolution Radiometer (AVHRR) and AVHRR/3 sensors have been carried on the US NOAA polar orbiting satellites since the 1980s. These data have been acquired via direct reception from the satellite by reception stations located in Australia. CSIRO has stitched together data received by different stations and agencies to compile a national high quality data set. The daylight satellite overpasses have been extracted from this data set for each day in the 30 year period commencing 1 April 1992. The data have been geolocated, and calibrated to produce imagery channels of solar reflectance and brightness temperature using community published methods. Satellite view and sun illumination angles for each pixel are provided, together with a preliminary cloud mask based on the CLAVR algorithm. The spatial resolution is ~1 km and temporal coverage is daily. The reprojected data set (in EPSG:4326, lon-lat) is available via the CSIRO EASI hub.