THE DETECTION AND MAPPING OF ALASKAN WILDFIRES USING A SPACEBORNE IMAGING RADAR SYSTEM

The study presented here focuses on using a spaceborne imaging radar, ERS-1, for mapping and estimating areal extent of fires which occurred in the interior region of Alaska. Fire scars are typically 3 to 6 dB brighter than adjacent unburned forests in the ERS-1 imagery. The enha nced backscatter from burned areas was found to be a result of high so il moisture and exposed rough ground surfaces. Fire scars from 1979 to 1992 are viewed in seasonal ERS-1 synthetic aperture radar (SAR) data obtained from 1991 to 1994. Three circumstances which influence the d etectability of fire scars in the ERS-1 imagery are identified and exa mined; seasonality of fire scar appearances, fires occurring in mounta inous regions, and fires occurring in wetland areas. Area estimates of the burned regions in the ERS-1 imagery are calculated through the us e of a Geographic Information System (GIS) database. The results of th is analysis are compared to fire records maintained by the Alaska Fire Service (AFS) and to estimates obtained through a similar study using the Advanced Very High Resolution Radiometer (AVHRR) sensor.