Quantifying the occurrence and magnitude of the Southeast Asian fire climatology

Current emissions inventories of black carbon aerosol, an important component of PM2.5 and a powerful climate altering species, are highly uncertain in both space and time. One of the major and hardest to constrain sources of black carbon is fire, which comes from a combination of forest, vegetation, agricultural, and peat sources. Therefore, quantifying this source more precisely in both space and time is essential. While there is a growing body of work on this topic, the best estimations generally underestimate measurements by integer factors. In this work, 12 years of measurements from 2000 through 2012 of AOD from the MISR satellite and AOD and AAOD from the AERONET network, are used to evaluate the aerosol climatology from Southeast Asian fires. First, the fires in Southeast Asia are uniquely characterized in both space and time to reveal two major burning regions: one with a regular inter-annual and intra-annual distribution, and the other with an irregular inter-annual and somewhat variable intra-annual distribution. These patterns correspond well with regional and local measurements of both composition and meteorology. Using these newly developed relationships, a new temporally and spatially varying set of black carbon emissions is developed. Finally, the best fits with the various measurements yield an annual average value for black carbon emissions due to fires bounded by the range 0.36–0.54 Tg yr ^−1 , with the amount in the year of the greatest fires being bounded by the range 1.2–1.8 Tg yr ^−1 . These magnitudes are significantly higher and differently distributed in space and time when compared with current inventories, and therefore are expected to have a significant impact on regional particulate loadings and the global climate system.