2013-05-08 13:36:28.0 [aaleman] Move Concepts delete narrower relation (null);
G - I
GTE
Scientific Objectives: This program will study the -biological sources of atmospheric chemicals -global distribution and long-range transport of chemical species -reactions in the troposphere that lead to the conversion, redistribution, and removal of atmospheric chemicals Project Description: The National Academy of Sciences in 1984 recommended initiation of a Global Tropospheric Chemistry Program (GTCP), in recognition of the central role of tropospheric chemistry in global change. The resources required are distributed among several federal agencies, scores of universities, and a variety of scientific disciplines-- including atmospheric science, biology, land processes, and oceanography. NASA's contribution to the GTCP is the Global Tropospheric Experiment (GTE), which utilizes large, extensively instrumented aircraft, along with satellite observations of meteorology, land use, and atmospheric chemical species to aid in experiment design and in the scientific analysis of results obtained from aircraft and ground-based measurements. The first series of projects carried out under the GTE was the Chemical Instrumentation Test and Evaluation (CITE) projects which exposed instruments aboard aircraft to a wide range of conditions in both polluted and and clean-air settings. CITE-1 was conducted in 1983 and consisted of a ground-based experiment at Wallops Island, Virginia and aircraft-based over California, southwestern U.S. and the central Pacific Ocean. CITE-2 was conducted in 1986 over California and the eastern Pacific, and CITE-3 was conducted in 1989 over Wallops Island, Virginia and the tropical Atlantic off the coast of Brazil. The advanced instruments validated by CITE have been used to carry out GTE field measurements. The initial field expeditions, the Atmospheric Boundary Layer Experiment (ABLE) projects, were designed to probe the interactions between the biosphere and the atmosphere. They measured the fluxes of gases between the surface and the atmospheric boundary layer (the tropospheric layer in direct contact with the surface) and the mixing of gases from the boundary layer into the 'free troposphere' above. The ABLE-1 experiment was conducted in 1984 over the tropical Atlantic from a base in Barbados; ABLE-2 was conducted in 1985 and 1987 over the Amazon region; ABLE-3 was conducted in 1988 and 1990 over Alaska and northern Canada. Future experiments scheduled for the early 1990's include: the Transport and Chemistry in the Atlantic (TRACE-A) which will investigate the distribution of atmospheric trace gases over the tropical Atlantic; also the Pacific Exploratory Mission (PEM) which will study atmospheric chemistry over the Pacific Basin. Data Used and Produced: GTE is primarily a aircraft-based program supplemented by ground-based measurements. The aircraft include the NASA Convair-990 and the Electra. Space Shuttle, Landsat, and the NOAA weather satellites are also being utilized. Global observations from space will ultimately be the technique of choice for mapping the distributions of reactive, spatially variable chemical species. Aircraft measurements will eventually provide 'ground truth' for satellite measurements and explore in detail the processes responsible for the observed distributions. The Public Archive of data collected on the NASA/GTE program consists of data from the CITE-1 Wallops Intercomparison Test in 1983 through the Amazon Boundary Layer Experiment (ABLE-2B) in 1987. These data are stored on various media including IBM-PC compatible diskettes, VAX 9-track tapes, tabular paper listings, plots, videos and other film products, as well as weather charts and summaries. 1. CITE-1 data: species measurements of methane, ozone, aerosols, carbon monoxide, nitric oxide, hydroxyl radical, hydrocarbons, non-methane hydrocarbons, sea salt, and ultraviolet flux, along with wind, temperature, and dew point. 2. CITE-2 data: species measurements of carbon monoxide, ozone, nitric oxide, nitrogen dioxide, reactive nitrogen, nitric acid, and peroxyacetyl nitrate. 3. ABLE-1 data: species measurements of ozone, aerosols, carbon monoxide, hydrocarbons, ammonia, and dimethyl sulfide. 4. ABLE-2A data: species measurements of sulfur gases, ozone, aerosols, nitric oxide, nitrous oxide, carbon dioxide, carbon monoxide, methane, particulate organic carbon, methylhalides, hydrocarbons, and halocarbons, along with surface fluxes of heat and water vapor, water chemistry, and tower meteorological measurements. 5. ABLE-2B data: species measurements of sulfur gases, ozone, aerosols, nitric oxide, nitrous oxide, carbon dioxide, carbon monoxide, methane, hydrocarbons, isoprene, radon 222, water vapor, peroxyacetyl nitrate, and organic acids, along with eddy heat and moisture fluxes, temperature, wind, radiation, rainfall, and water chemistry. Project Archive Contact: EOSDIS Langley DAAC NASA Langley Research Center Mail Stop 157B Hampton, VA 23681-0001 Phone: (804) 864-8656 FAX: (804) 864-8807 Email: userserv@eosweb.larc.nasa.gov WWW Home Page: http://eosweb.larc.nasa.gov/ Project Manager Contact: James Hoell NASA Langley Research Center Mail Stop 483 Hampton, VA 23681-0001 Phone: (804) 864-5826 FAX: (804) 864-5841 Email: j.m.hoell@larc.nasa.gov References: Drewry, J. W., and D. W. Owen, 1989: Global Tropospheric Experiment Data Archive Catalog, NASA Langley Research Center. Global Tropospheric Experiment Brochure WWW: "http://www-gte.larc.nasa.gov/gte_hmpg.htm"