The Interannual Variability of Biomass Burning in North America using MODIS Data: Observations and Meteorological Influences

Meteorological impacts on the interannual variability of wildfires in North America including Alaska are investigated using six years of the MODIS fire and Aerosol Optical Depth (AOD) products, the meteorological data from North American Regional Reanalysis (NARR), and the lightning data collected by the National Lightning Detection Network (NLDN). The relationships of MODIS fire counts, fire radiative power, and AOD with over 13 meteorological variables were investigated in four sub-regions of the North American continent (Alaska, western U.S., Québec, and the rest of Canada). Atmospheric instability and anomalies in the 500 hPa geopotential height field explain more than 60% of the interannual variability in wildfires in Alaska and Quebec; while in the western Unites States, pre-season precipitation is a dominant factor. Lightning strike data show little correlation with fire counts in the western United States, suggesting the importance of anthropogenic cause of fires in this region. Relationships between fire occurrence, atmospheric instability, and smoke production were also investigated. It is revealed that although the Haines Index is widely used for fire forecasting, it is not sufficient to interpret the interannual variability of fires in Boreal North America, but its performance improves when used with 500mb geopotential height anomalies. Continuing work will focus on the meteorological impact and interannual variability of smoke production and subsequent transport between regions. In addition, analysis using lightning strike data may also be preformed for the Canada and Alaska regions via Environment Canada and the Bureau of Land Management (BLM) respectively.