September October 2014

The figure above shows OMI observed and TM5 modeled NO2 tropospheric columns as well as MODIS Terra + Aqua cloud corrected monthly fire counts (MOD14CMH + MYD14CMH) for July-September, 2005, a year of severe drought for the Amazon.  Observed and modeled NO2 concentration enhancements correlate well spatially and temporally with observed active fires.  However, in July, TM5 tends to under predict OMI NO2 columns, while in August and September TM5 NO2 columns are higher than observations by more than a factor of 2 in central Brazil and Bolivia; areas where deforestation is the primary source of fire emissions.  Our modeling suggests that NOx emission factors for deforestation burning were significantly lower than conventional estimates used in bottom-up fire emissions modeling, possibly because prolonged dry spells led to a larger contribution of smoldering combustion from large diameter fuels.

  © Maarten Krol 2016