What: Ph.D. Dissertation Defense
Who: E. Natasha Stavros
When: Friday, Aug. 9 @ 2 pm
Where: Bloedel 292
Committee: Ernesto Alvarado-Celestin (Chair), Donald McKenzie, Christian Torgersen, Narasimhan Larkin, David Peterson, Tara Strand, Timothy Essington (GSR)
Dissertation: Understanding climate and very large wildfires in the Western United States at scales for modeling air quality
Wildfires, especially the largest ones, can have lasting ecological and social effects both directly on the landscape and indirectly on the atmosphere and climate; thus making them a part of a much more complicated system. Both climate and fire regimes are expected to change into the future while air quality, the composition of the near surface atmosphere, continues to be regulated. It is necessary to understand how climate, wildfire, and air quality interact to mitigate air quality. There are limited studies, however, at spatial and temporal scales appropriate to integrate climate, wildfire, and air quality data. To begin to study the interactions among these three components, evidence from very large wildfires, here defined as megafires, provides a useful starting place. Megafires contribute to significant degradation in air quality and consequently climate. In this dissertation, I demonstrated, using a systematic approach, that broad spatial and fine temporal resolutions are the best scales by which to understand how climate, wildfire, and air quality interact. Thus, using broad wildfire data aggregated to the spatial scale of eight US National Interagency Fire Center Geographic Area Coordination Centers (GACCs) across the western contiguous US, and daily and monthly climate data, I developed logistic regression models to predict the probability that a megafire will occur in a given week. Significant climate predictors of megafires vary by GACC and are similar to those found by other studies for aggregate annual area burned. Thus megafires may influence the analysis of aggregate statistics substantially. For all eight GACCs, projecting these models showed a significant (p≤0.05) difference between the historical period from 1979 to 2010 and both Intergovernmental Panel on Climate Change future scenarios, representative concentration pathways (RCPs) 4.5 and 8.5, during 2031 to 2060. Generally, with the exception of the Southwest and Northern California, megafires will be more likely both throughout the fire season and from year to year, with more pronounced patterns under RCP 8.5 than RCP 4.5. This research provides a political and managerial motivation to analyze the effects of a changing climate on air quality degradation from megafires.
Filed under defense, grad