A PILOT RESEARCH MOORED ARRAY IN THE TROPICAL ATLANTIC (PIRATA)

The tropical Atlantic Ocean is characterized by a large seasonal cycle around which there are climatically significant interannual and decad al timescale variations. The most pronounced of these interannual vari ations are equatorial warm events, somewhat similar to the El Nino eve nts for the Pacific, and the so-called Atlantic sea surface temperatur e dipole. Both of these phenomena in turn may be related to El Nino-So uthern Oscillation variability in the tropical Pacific and other modes of regional climatic variability in ways that are not yet fully under stood. PIRATA (Pilot Research Moored Array in the Tropical Atlantic) w ill address the lack of oceanic and atmospheric data in the tropical A tlantic, which limits our ability to make progress on these important climate issues. The PIRATA array consists of 12 moored Autonomous Temp erature Line Acquisition System buoy sites to be occupied during the y ears 1997-2000 for monitoring the surface variables and upper-ocean th ermal structure at key locations in the tropical Atlantic. Meteorologi cal and oceanographical measurements are transmitted via satellite in real time and are available to all interested users in the research or operational communities. The total number of moorings is a compromise between the need to put out a large enough array for a long enough pe riod of time to gain fundamentally new insights into coupled ocean-atm osphere interactions in the region, while at the same time recognizing the practical constraints of resource limitations in terms of funding , ship time, and personnel. Seen as a pilot Global Ocean Observing Sys tem/Global Climate Observing System experiment, PIRATA contributes to monitoring the tropical Atlantic in real time and anticipates a compre hensive observing system that could be operational in the region for t he 2000s.