The Central Pacific El Niño and its impact on weather and forest fire patterns in western North America

• Main Author: Banholzer, Sandra
• Format: Thesis
• Language: English
• Published: University of British Columbia 2012
• Subjects: Arctic; Canada; Pacific; Alaska
• Online Access: http://hdl.handle.net/2429/42949

The El Niño/ Southern Oscillation (ENSO) is known to influence the weather in western North America through teleconnections. Several studies have established a relationship between ENSO and forest fire occurrence. However, a recently discovered variant of ENSO, called Central Pacific El Niño, may cause a different teleconnection and forest fire pattern. Investigating and classifying past El Niño events and their possible influence on weather and forest fire patterns in western North America from 1981-2010 was the objective of this study. The analysis revealed that current El Niño classification methods are suboptimal and that a binary distinction leads to misclassification of events. It, however, confirms that the two types show a different warming pattern as well as different wind and precipitation patterns. These characteristics of the Central Pacific El Niño can cause different extra tropical teleconnections in western North America than the canonical El Niño. Variation of teleconnections within the events and the limited amount of events, however, complicate a clear conclusion. Further, other oscillations such as the Arctic Oscillation play a major role in impacting the climate in western North America. Exploratory analysis of natural forest fires of North America identified hot spots of annual area burned in central Alaska, north-west and central Canada and western United States. Further, singular value decomposition and spatial correlation analysis revealed a different teleconnection response in summer drought patterns over western North America related to the two types of El Niño. The drought pattern is significantly related with forest fire frequency and area burned in certain regions across western North America. A clear connection between the different El Niño types and the forest fire pattern however remains inconclusive.