Biomass burning is an important source of many atmospheric greenhouse gases and photochemically reactive trace gases. Considerable research has been conducted to understand the emissions of these compounds and aerosol particles from biomass burning in the tropics. However, there are limited data available on the spatial and temporal extent of biomass fires and associated CO2, CO, and CH4 emissions in North America. The information is essential for quantifying the North American terrestrial carbon budget and the biogeochemical cycles of these trace gases. We propose to develop a daily emissions inventory of CO2, CO, and CH4 from biomass fires in the United States, Canada, and Mexico with a 1-km x 1-km resolution for seven years from 2001 to 2007. This interdisciplinary project will be accomplished using a variety of approaches. MODIS data from Terra and Aqua satellites will be used to detect fire locations and map burned areas. We will validate MODIS algorithms for fire detection and burned areas in different ecosystems in Canada and Mexico. Emissions of CO2, CO, and CH4 will be measured from 30 experimental fires and 10 wildfires in semiarid, temperate, and tropical ecosystems in Mexico. We will develop daily, weekly, seasonal, and interannual variability of CO2, CO, and CH4 emissions from biomass burning in the U.S., Canada, and Mexico. Biomass burning sources will be compared with the sources of fossil fuel combustion and industrial processes for CO2, CO, and CH4 emissions in various regions of the United States, Canada, and Mexico. The results will reduce the uncertainty in the emissions of these compounds from biomass burning in North America and are critical for developing an effective carbon management policy. We will study the effects of long-range transport of smoke plumes on atmospheric chemical composition. Carbon monoxide, CO2, and CH4 concentrations downwind from large fires will be investigated using the Stochastic Time-Inverted Lagrangian Transport (STILT) model and the estimated emission rates of these trace gases every 6-8 hours from large fires in North America in May and June 2003, when the COBRA mission was conducted. Model-computed CO, CO2, and CH4 concentrations will be compared with previous, independent measurements during the COBRA mission. In addition, the daily emissions inventory in North America and emission rates every 6-8 hours for selected large fires in North America will be provided to the science teams of the ICART2 field campaigns, including the NASA INTEX-NA component, in the summer of 2004. ICART2 is an International Consortium for Atmospheric Research on Transport and Transformation. We will also study atmospheric CO, CO2, and CH4 levels downwind from selected large fires and verify our estimated emission rates during the ICART2 campaigns.