The project, GARP Atlantic Tropical Experiment (GATE), is the 

 first major international field experiment in GARP of the World 

 Meteorological Organization and the International Council of 

 Scientific Unions. Coordination of United States participation in the 

 experiment is assigned to NOAA. 



The key objectives of GATE, as a major part of GARP, are to study 

 the structure and evolution of weather systems in the tropical 

 eastern Atlantic and to assess the extent to which these tropical 

 disturbances affect the circulation of the whole atmosphere. 



As weather systems are closely coupled to related oceanic 

 processes and circulation features, oceanographic studies are 

 integral to the design of the experiment. The oceanographic studies 

 focus on two aspects with broad scientific and practical importance. 

 The first is the complex equatorial current system, closely related to 

 oceanic upwelling processes and to the atmosphere's intertropical 

 convergence zone. Understanding of this major feature of oceanic 

 circulation is vital to the development of ocean models. The second 

 focus of the oceanographic program is the interaction of the ocean's 

 upper layers with the atmosphere and with organized convective 

 systems. 



The broad area of the experiment includes the entire tropical 

 Atlantic and the adjacent continental regions (about 10 degrees 

 south to 20 degrees north latitude, 47 degrees east to 95 degrees west 

 longitude). A selected smaller area, a hexagon with 90 nautical mile 

 sides centered 8.5 degrees N and 23.5 degrees W, will be the subject of 

 intensive observations with ships and aircraft. 



Thirteen nations, including Brazil, Canada, the Federal Republic of 

 Germany, the German Democratic Republic, Finland, France, 

 Mexico, the Netherlands, Portugal. Senegal, U.S.S.R., the United 

 Kingdom, and the United States have made substantial 

 commitments to the experiment, and many other countries in 

 Europe, South America, and Africa have expressed their interest in 

 participating. Dakar, Senegal, will be the principal base of 

 operations. 



The experiment, which is divided into three 21-day observational 

 periods, will involve 37 ships and about a dozen instrumented 

 aircraft supplemented by instrumented buoys and constant level 

 balloons, operational sun-synchronous and geostationary satellites, 

 and the augmented World Weather Watch network of continental 

 and island-based weather stations. U.S. participation will include at 

 least four oceanographic ships equipped with sophisticated 

 meteorological instrumentation and another four vessels to be 

 devoted only to oceanographic studies, as many as eight 

 instrumented aircraft, polar-orbiting and geostationary satellites, 

 and a variety of buoys. 



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