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GTE Missions |
The map below shows the geographical regions for the GTE campaigns. The Chemical Instrumentation Test and Evaluation (CITE-1,-2 and -3) experiments were initiated to evaluate our ability to measure critical tropospheric species; the field studies known as Atmospheric Boundary Layer Experiment (ABLE -1, -2A and -2B, and -3A and -3B) were conducted to study major ecosystems that are known to exert a major influence on global chemistry and, in some cases, are undergoing profound changes; and the impact of long range transport of continental emissions, natural and anthropogenic, have been studied through the field campaigns Transport and Chemistry near the Equator in the Atlantic (TRACE-A), the Pacific Exploratory Missions in the Pacific (PEM West-A and -B, PEM-Tropics A and B), and the recent (March/April 2001) Transport and Chemistry Experiment in the Pacific (TRACE-P).
Three CITE mission have been conducted as part of GTE - CITE-1,-2,-3. The central objective of CITE 1 focussed on the evaluation of instrumentation for measuring carbon monoxide (CO), nitric oxide (NO), and the hydroxyl radical (OH). CITE-1 consisted of a ground-based campaign Wallops Island, VA in the Summer 1983 (CITE-1A); an airborne campaign based out of the NASA Ames Reaseach Center, CA and Hickham Air Base, Hawaii in the Fall 1983 (CITE-1B); and a second airborne campaign based from Ames Reseach Center in the Spring 1984 (CITE-1C). The two airborne components of CITE-1 were conducted aboard the NASA CV-990 aircraft. The GTE Data Table lists the parameters available in the CITE-1 data and provides a link to the GTE home site for access to the CITE-1 data files.
The CITE-2 mission focused on intercomparison of techniques for measuring nitrogen dioxide (NO2), nitric acid (HNO3) and peroxyacetylnitrate (PAN), as well as a re-evaluation of NO techniques. CITE-2 was based from the NASA Wallops Flight Faciltiy, Wallops Island, VA and Natal, Brazil and was conducted aboard the NASA Electra aircraft. The GTE Data Table lists the parameters available in the CITE-2 data and provides a link to the GTE home site for access to the CITE-2 data files.
The CITE-3 mission focused on intercomparison of techniques to measure key sulfate species sulfur dioxide (SO2), dimethylsulfide (DMS), hydrogen sulfide (H2S), carbonyl sulfide (COS), and carbon disulfide (CS2). CITE-3 was based from the NASA Wallops Flight Faciltiy, Wallops Island, VA and Natal, Brazil and was conducted aboard the NASA Electra aircraft. The GTE Data Table lists the parameters available in the CITE-3 data and provides a link to the GTE home site for access to the CITE-3 data files.
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The ABLE-1, conducted in 1984 from Barbados, focused on the chemistry and transport processed over the tropical Atlantic ocean and the rain forest of French Guyana. The ABLE-2, based in Manaus, Brazil, focused on the chemistry and transport over the Amazon Rain Forest during the dry season of 1985 (ABLE-2A) and during the wet season of 1987 (ABLE-2B). The ABLE-3 mission, also conducted in 2- phases, focused on the chemistry in the northern latitude and the Arctic tundra as a source/sink of methane (CH4), ozone (O3), and CO. The first phase, ABLE-3A was conducted in 1988 from bases in Point Barrow and Bethel, Alaska. The second phase, ABLE-3B was conducted in 1990, from bases at North Bay and Goose Bay, Canada and a major ground site in Schefferville, Canada. Each of the ABLE missions employed the NASA Electra aircraft instrumented for in situ measurements of atmospheric gases and aerosol and as well as high speed measurements of the verical and horizontal components of the local winds. The GTE Data Table lists the parameters available in the ABLE data archives and provides a link to the GTE home site for access to the ABLE 1 and 2 data files and to the ASDC web ordering site for the ABLE 3 data files.
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During the 1990's, the GTE field studies focused on the impact of long range transport of trace gases on the chemistry of the free troposphere. The Pacific Exploratory Mission-West (PEM-West) focused on characterizing the impact of the natural and anthropogenic emission from the Asian continent on the chemistry of the troposphere over the western North Pacific ocean. PEM-West encompassed two field campaigns during the two major contrasting meteorological regimes in the north western pacific. The first, PEM-West(A), was conducted September/October (1991), a period of minimum out-flow from the Asian continent. PEM-West(B) was conducted during February/March (1994), a period of maximum outflow from the Asian continent. PEM West A and B employed the NASA DC-8 equipped with instrumentation for measuring numerous chemical compounds and aerosols. Major deployment sites included Hong Kong, the Yokota Air Base near Tokoyo, Japan, and Guam. The GTE Data Table lists the parameters available in the PEM-West A and B data archive and provides a link to the ASDC web ordering site for the downloading data files on a flight-by-flight basis.
The Transport and Chemistry near the Equator in the Atlantic (TRACE-A) experiment, conducted in September/October 1992 investigated the distribution of atmospheric trace gases over the tropical south Atlantic. This portion of the Atlantic troposphere is impacted by atmospheric-transport of emissions from both South America and southern Africa. The objectives of TRACE-A focussed on determining the relative importance of natural versus amthropogenic emmision/processes on the formation of a seasonal enhancement of tropospheric O3 over a large region of the South Atlantic ocean off the coast of Brazil and southern Africa. TRACE-A employed the employeed the NASA DC-8 equipped with instrumentation for measuring numerous chemical compounds and meteorological parameters. Major deployment sites included Brasilla, Brazil; Johannesburg, South Africa; Windhoek, Namibia; and Ascension Island. The GTE Data Table lists the parameters available in the TRACE-A data archive and provides a link to the ASDC web ordering site for the downloading data files on a flight-by-flight basis.
The central objective of The Pacific Exploratory Mission in the Tropical Pacific (PEM-Tropics) was to improve knowledge of the factors controlling ozone, OH, aerosols, and related species over the tropical Pacific. PEM-Tropics A was conducted in September-October 1996 the dry season if the southern tropical and encountered considerable influence from the long range transport of biomass burning products. PEM-Tropics B, conducted in March-April 1999 during the wet season of the southern tropics, and observed an exceedingly clean atmosphere over the South Pacific but a variety of pollution influences over the tropical North Pacific. Both phases of PEM-Tropics employed the NASA DC-8 and P-3B aircraft equipped with instrumentation for measuring numerous chemical compounds and aerosols. Major deployment sites during phase A included Christmas Island; Tahiti; Fiji; Christchurch, New Zealand and Easter Island. Major deployment sites during phase B included Hilo, Hawaii; Christmas Island; Tahiti; Fiji; and Easter Island. The GTE Data Table lists the parameters available in the PEM-Tropics A and B data archive and provides a link to the ASDC web ordering site for the downloading data files on a flight-by-flight basis.
The objectives of the Transport and Chemistry Experiment in the Pacific (TRACE-P), conducted in March/April 2001, were 1) determine the chemical composition of the Asian outflow over the western Pacific in spring in order to understand and quantify the export of chemically and radiatively important gases and aerosols, and their precursors, from the Asian continent and to 2) determine the chemical evolution of the Asian outflow over the western Pacific in spring and to understand the ensemble of processes that control the evolution. TRACE-P employed the NASA DC-8 and P-3B aircraft equipped with instrumentation for measuring numerous chemical compounds and aerosols. Major deployment sites included Hilo, Hawaii; Hong Kong, and the Yokota Air Base near Tokoyo, Japan. The GTE Data Table lists the parameters available in the TRACE-P data archive and provides a link for downloading data files.
