One of the original objectives of the PIRATA program has been to document and investigate basin-scale ocean–atmosphere exchanges in the tropical Atlantic and their role in regional climate variability on seasonal to decadal timescales. Over the years, numerous studies have highlighted the interannual variability of the tropical Atlantic, notably through the identification of two dominant climate modes: an equatorial mode and a meridional mode, both exerting strong influences on adjacent regions of Africa and South America. Additional long-standing objectives include the study of the northern tropical Atlantic, a key region for tropical cyclone genesis affecting the Caribbean and the southeastern United States, as well as interactions between the tropical and temperate Atlantic and links with Pacific climate variability associated with ENSO.

After an initial four-year pilot phase followed by a four-year consolidation phase, PIRATA has become a mature and well-established observing system, operating efficiently for more than 27 years. Following international evaluations by CLIVAR and the Ocean Observations Panel for Climate (OOPC) in 2006, and more recently within the framework of the Tropical Atlantic Observing System (TAOS) review initiated in 2018 by the CLIVAR Atlantic Region Panel in collaboration with GOOS and GCOS, PIRATA is now recognized as the backbone of the tropical Atlantic observing system. Its long-term observations of Essential Climate and Ocean Variables (ECVs and EOVs) make it a cornerstone for climate monitoring in the tropical Atlantic, in line with the objectives of the UNESCO Intergovernmental Oceanographic Commission.

Building on its historical foundations, PIRATA has continued to evolve. The 20th anniversary of the program, marked by a dedicated conference in Fortaleza in 2017, led to a comprehensive synthesis of the network’s evolution, major scientific achievements, and future perspectives within TAOS. The PIRATA array of 18 moorings provides an essential complement to programs monitoring large-scale ocean transports, such as the Atlantic Meridional Overturning Circulation (AMOC), by capturing intertropical meridional circulations and equatorial recirculations. Beyond its operational use in meteorological, oceanographic, and climate forecasting centers, PIRATA’s unique long-term time series now support studies of interannual to decadal climate variability, climate trends, and emerging environmental issues, including ocean deoxygenation, air–sea CO₂ fluxes, river plume impacts, and the proliferation of Sargassum across the tropical Atlantic. Sustaining PIRATA over the long term is therefore essential to improving our understanding of climate variability and change in response to anthropogenic forcing.