Detection of Active Wildland Fires Using Multitemporal MODIS Images

The fire fractional area and radiances at 4 and 11 ¿m of active fires in the boreal forests in Siberia and Mongolia were estimated using Advanced Spaceborne Thermal Emission and Reflection Radiometer images. In addition, a stochastic fire model was constructed. The efficiency of a biband threshold method used for detecting active fires on the basis of the thermal anomaly obtained from multitemporal Moderate Resolution Imaging Spectroradiometer (MODIS) images was evaluated using the stochastic fire model. The simulation results of fire detection indicated that the aforementioned method accurately detected 80% of the fire pixels with false alarms that were less than 2 x 10
^-5
when the radiances of the nonfire pixels at 4 and 11 ¿m were estimated using past MODIS images with a standard deviation (SD) of 1 K. The analyses also indicated that, in order to obtain fewer errors than those obtained using the conventional contextual algorithm (MOD14) from the objective area (omission errors that are less than 62% and commission errors that are less than 2 x 10
^-5
), it is essential to carry out the nonfire radiance estimation using past images with an SD of less than 3 K. During an actual application of the multitemporal method to several fire cases, fewer errors occurred than those that occurred using MOD14.