Title: Fire predictability in the Earth system
Abstract: Fires play an import role in the Earth system by shaping and influencing terrestrial ecosystems, atmospheric environment, and the carbon cycle. Climate, as a fundamental constraint on fire activity, can regulate the buildup and drying of fuels and the conditions for fire ignition, spread, and termination. We investigated global fire responses to large-scale climate variations at or before the fire season, and explored the use of sea surface temperature (SST) variations in seasonal fire forecast. We found the year-to-year changes in fire activity in South America were closely linked with ENSO and North Atlantic SSTs. Using the SST information, we developed an empirical model to forecast regional fire season severity in South America with lead times of 3-5 months. We also found the terrestrial water storage observations from GRACE satellite have the potential to improve the forecast. Multiple lines of observational evidences suggested that ENSO initiated a pan-tropical cascade of fire impacts, and was the strongest single predictor of interannual variability in global fire. By systematically evaluating burned area data from Global Fire Emissions Database (GFED), we found ~48% of global burned area can be predicted using SSTs from different ocean regions.