Blue Flower

Spotting fires from Space

Incident Alert is now mapping heat sources located by two satellites on our main map page as a trial for the 2010/11 fire season.

We are utilising a small proportion of the data from two NASA satellites called Terra (launched 1999) and Aqua (launched 2002) to map anomalies in reflected heat in attempting to identify bushfire progression over 48 hours.

How it works

Each Satellite orbits the earth over the two poles and maps an area of approximately  2330 km by 10km at a time. It takes up to two days to map the entire globe. Data is returned to earth and a list of potential heat sources is extrapolated around fours later which also shows a level of confidence.

Fires need to be at least one square kilometre to be identified although smaller fires will be recognised on occasions. Identification of fires can be hindered by extensive smoke, clouds and forest canopy. A fire in scrubby desert will be identified more easily than a larger fire that is smouldering fire under a canopy.


Display of data

Currently we display data that appears to have a 40% confidence level or more up to 48 hours since the scan although this may change without notice. Only fires in SA, Vic, NSW, southern Queensland and Tasmania will be shown although other states and NZ may appear from time to time for testing purposes.

As the data ages we degrade the dots. The example is a fire that is burning towards Four Ways in Queensland. The first scan 44 hours ago picked up five hot spots in the top left corner. The next two scans saw the fire move south east and increase in size. The final five bright dots show the fire from around five hours ago. Dots are shaded orange if the confidence is under 75%. The gaps between the dots are areas burnt whilst the satellites were scanning elsewhere.

 
 

Accuracy

Heat spots are only accurate at best to one square kilometre and greater the closer to the edge of the scan line. It doesn't matter how far you zoom in, the data is still limited to being an estimation of where the heat source is. It also takes between four and six hours to show the data collected by the satellite due to data transfer speeds between the satellite and ground stations (6.1 Mbit/s on average).

 

A recent fire at Londonderry, near Penrith, NSW shows four heat spots with only one of these bordering the actual burnt area. Dots located near each other does not mean that you can assume the area between has been totally affected.

 

Credits

 Incident Alert thanks the University of Maryland for FIRMS and NASA for the satellite data.

NASA/University of Maryland, 2002. MODIS Hotspot / Active Fire Detections. Data set. MODIS Rapid Response Project, NASA/GSFC [producer], University of Maryland, Fire Information for Resource Management System [distributors]. Available on-line