Remote classification of head and backfire types from MODIS fire radiative power and smoke plume observations

Abstract

The classification of savanna fires into headfire and backfire types can in theory help in assessing pollutant emissions to the atmosphere via relative apportionment of the amounts of smouldering and flaming combustion occurring, and is also important when assessing a fire’s ecological effects. This paper provides a preliminary assessment of whether a combination of visible and thermal satellite remote sensing can be used to classify fires into head and backfire categories. Remote determination of the fire radiative power, alongside assessments of the prevailing direction of the wind (through identification of the fire-related smoke plumes) and the fire front propagation (through its relation to the previously burned area) were used to infer the fire type category and to calculate ‘radiative’ fireline intensity (FLI). The ratio of radiative FLI for the head and backfire categories was found similar to that of in situ fireline intensity measurements, but the magnitudes of the radiative FLI values were around an order of magnitude lower. This agrees with other data suggesting that a fire’s radiative energy is around an order of magnitude lower than the fuel’s theoretical heat yield, and suggests that the remote measurement of radiative FLI and classification of headfire and backfire types is a realistic proposition for large wildfire activity.