Understanding how well satellites detect fires

Detection and reporting of fires is important for tracking fire's effects and impacts from the local to global scale. Currently, active satellite fire detections provide fire occurrence information on local to global scales and are often employed to estimate daily, yearly, and decadal fire emissions. Several active fire detection methods, which employ unique algorithms and utilize various satellite data streams, have been developed and are in operational use today. Quantification of the probability of detection of fires is critical to properly evaluate emissions inventories and smoke forecast prediction errors. We have cross-evaluated active fire detection rates from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Hazard Mapping System (HMS) with 4,246 reference fires from the Monitoring Trends in Burn Severity project. Detection rates generally decreased with decreasing fire size and both HMS and MODIS missed a considerable fraction of fires. Most missed fires were small; however, both methods unsuccessfully detected fires of several thousand acres in size.