Thursday, August 7, 2008
Exhibit Hall CD, Midwest Airlines Center
Jorge M. De Paz Jr., University of California, Irvine, Irvine, CA, James T. Randerson, Department of Earth System Science, University of California, Irvine, Irvine, CA, Guido R. Van der Werf, Vrije Universiteit and Louis Giglio, NASA Goddard Space Flight Center
Background/Question/Methods: The current practice of land clearing with the aid of human-set fires on the perimeter of the Amazon rainforest is causing a loss of forest cover with substantial year-to-year variability. The causes of this variability are not well understood and may include both economic and climate factors. Here we report changes in fire activity over the last decade using multiple satellite data sources, including active fire observations from the Tropical Rainfall Measuring Mission Visible and Infrared Scanner (TRMM VIRS; 1998-2007) and the MODerate resolution Imaging Spectroradiometer on Terra and Aqua satellites (MODIS; 2000-2007). We also analyzed fire emissions from the Global Fire Emissions Database version 2 (GFEDv2; 1997-2007).Results/Conclusions:
All of the different fire products showed an increasing trend in fire activity for the state of Amazonia in Brazil, with rates of 14.8%•yr-1 for MODIS, 7.7%•yr-1 for TRMM, and 6.1%•yr-1 for GFEDv2. For the legal Amazon Basin as a whole, fire activity remained constant or showed a weak linear increase depending on the fire product and time period analyzed. Mato Grosso and Para had the highest levels of fire emissions (with means of 107 and 42 Tg of C•yr-1) whereas Mato Grosso and Rondonia had the highest density of fire emissions per unit of land area (with means of 118 and 104 g of C•m-2•yr-1). Precipitation at the onset of the dry season explained a substantial amount of the inter-annual variability of fire emissions, with correlation coefficients of -0.57 for the state of El Beni in Bolivia, and -0.78, -0.86, -0.43, -0.70, respectively, for the states of Amazonia, Mato Grosso, Para, and Rondonia in Brazil. Comparison with aerosol optical depth and carbon monoxide satellite observations corroborated the fire emissions trends.
