PIRATA observations play a key role in understanding the climatic and biogeochemical trends in the tropical Atlantic. With continuous in situ time series available since the late 1990s, PIRATA has documented the strengthening of the Equatorial Undercurrent and its effects on subsurface oxygenation (e.g, Brandt et al., 2021), while validating long-term trends of sea surface warming, strengthened trade winds, and sea-level rise observed since the 1960s (Servain et al., 2014). Measurements at the 6°S–10°W mooring also reveal the variability and evolution of CO₂ fluxes, confirming the equatorial Atlantic as a net CO₂ source whose intensity has been increasing over time (Lefèvre et al., 2024). By linking these physical, dynamical, and biogeochemical changes, PIRATA provides a unique foundation for disentangling natural variability from the anthropogenic impacts in the tropical Atlantic climate system.
