Wildfires in Alaska and Canada in 2004 emitted about as much carbon monoxide as did human-related activities in the continental United States during the same time period, according to new research by the National Center for Atmospheric Research (NCAR). The fires also increased atmospheric concentrations of ground-level ozone across much of the Northern Hemisphere.
Wildfires in Alaska and western Canada were particularly intense in the summer of 2004, largely because of unusually warm and dry weather. To quantify carbon monoxide emissions from the fires, the research team used a remote sensing instrument known as MOPITT (Measurements of Pollution in the Troposphere) that is operated by NCAR and the University of Toronto and flown on NASA’s Terra satellite. The scientists simulated the transport of the pollutants emitted by the fires and the resulting production of ozone with an NCAR computer model called MOZART (Model for Ozone and Related Chemical Tracers).
The team confirmed its results by using numerical techniques to compare simulated concentrations of carbon monoxide in the atmosphere with measurements taken by MOPITT. The researchers were able to get further confirmation by analyzing data from aircraft-mounted instruments that were taking part in a field project over North America and Europe.
The NCAR study, which indicates the extent to which wildfires contribute to atmospheric pollution, was published this month in Geophysical Research Letters. The researchers used a novel combination of observing instruments, computer models, and numerical techniques that allowed them to distinguish between carbon monoxide coming from the wildfires and from other sources. The team concluded that the Alaskan and Canadian wildfires emitted about 30 teragrams of carbon monoxide from June through August of last year. Because of the wildfires, ground-level concentrations of ozone increased by 25% or more in parts of the northern continental United States and by 10% as far away as Europe. The research was funded by a NASA grant in partnership with the National Science Foundation, which is the primary sponsor of NCAR.