Recent information suggests that on the global scale, biomass burning is much more extensive and widespread than previously thought. Biomass burning refers to the burning of the world's forests and grasslands and agricultural lands following the harvest for land clearing and land conversion. Biomass burning is a global phenomenon occurring in the tropics (tropical rain forests and savanna grasslands), in the temperate zone and in the boreal forest.

      GTE utilizes large, extensively instrumented aircraft as primary research tools. However, GTE also draws heavily upon satellite observations of meteorology, land use and atmospheric chemical species to aid in experiment design and in the scientific analyses of results obtained from aircraft and ground-based measurements. The GTE, managed through the Tropospheric Chemistry Program in the Earth Science Division, Science Mission Directorate at NASA Headquarters, was initiated in the early 1980s. Implementation of the GTE Project is the responsibility of the Science Directorate at the NASA Langley Research Center.

      Atmospheric modeling and simulation studies have been invaluable in the development of our current level of understanding of the fundamental processes of radiation, chemistry and dynamics that ultimately determine the circulation, thermal structure and distribution of constituents in the Earth's atmosphere. Many of these studies have treated the processes independently or have suppressed important couplings between them. This approach was a conscious strategy adopted to make the studies tractable and often relied on assumptions that the couplings were weak enough to neglect. Recently however, there has been increased awareness that many phenomena of interest may involve subtle and complex interactions among these processes.

      The LiDAR group at NASA Langley Research Center has been developing and applying advanced lidar systems to a broad range of atmospheric investigations. These activities have included the development and application of airborne Differential Absorption Lidar (DIAL) systems for studies of ozone, water vapor, aerosols and clouds.

      Scientists use the RAQMS computer model to predict air quality around the globe. RAQMS has been designed to address the atmospheric chemistry modeling needs for NASA's Earth Science Enterprise science missions and to prototype future NASA, NOAA and EPA operational air quality prediction systems.

      Scientists now have a new data set to view the past two decades of ozone in the lower atmosphere. Using a technique pioneered by a Langley scientist, researchers have completed daily maps of ozone in the lower atmosphere between 50 degrees north and 50 degrees south from 1979 to 2000. The database is available at the TOR Web site.