As part of NASA’s Earth Observing System (EOS),Moderate Resolution Imaging Spectrometer (MODIS) is carried on both the Terra and Aqua satellites. MODIS fire observations are made four times a day from the Terra AM (10:30 and 22:30) and Aqua PM (13:30 and 01:30) platforms. Active fire detection for MODIS is based on improved algorithms in lieu of heritage algorithms developed for the Advanced Very High Resolution Radiometer (AVHRR) and TRMMVIRS [Kaufman et al., 1998], with superior sensitivity to smaller, cooler fires and yielding fewer blatant false alarms.