Wildfire and climate interactions across the Southwest United States

Abstract

Variability in climate and wildfire activity are inextricably linked through complex and often poorly understood processes. The studies presented in this dissertation examine fire-climate relationships across the southwestern United States at different temporal and spatial scales. Collectively, they identify that low-frequency and high-frequency changes in climatic variables important to wildfire are connected through teleconnection patterns originating in the tropical and extratropical Pacific Ocean (El Nino-Southern Oscillation [ENSO] and Pacific Decadal Oscillation [PDO]). Variability in precipitation years prior to a wildfire season appears to affect the overall number of fires and total area burned by either promoting or limiting the growth of fine fuels and also controlling moisture levels in heavy fuels. The same mechanisms (ENSO & PDO) that play a role in precipitation variability across the Southwest also appear to modulate the frequency of extreme fire weather events during the spring fire season. Identifying links between high and low frequency climatic variables important to wildfire variability provides additional insight into the complex mechanisms that link wildfire and climate. The results of this dissertation will aid in improving wildfire planning efforts that extend seasons to decades into the future.