The PIRATA sea campaigns take place every year to ensure the long-term maintenance of a wide range of oceanographic instruments deployed in the tropical Atlantic Ocean:
- Eighteen fixed anchorages measure the weather and ocean conditions on a continuous basis; six of them are maintained by France in the central and eastern part of the basin, on the Gulf of Guinea side;
- Three current meter anchorages maintained along the equator complete the network to monitor the current in the first 300 metres;
- Hydrological profiles of pressure, temperature and salinity are collected at certain points along the way, with the ship stopped, thanks to a rosette equipped with CTDO2 sensors (acronym for Conductivity-Temperature-Salinity-Oxygen) which are lowered from the surface to a depth of 2,000 metres (sometimes over 5,000 metres);
- Finally, chemical and biological measurements are made on water samples taken during each mission at certain points in the work area.
All these measurements are used to validate and correct in real time numerical forecasting models for seasonal, weather, climate and oceanic conditions. They are integrated into a number of oceanic databases and used by scientists in their analyses dedicated to a better understanding of oceanic processes influencing exchanges between the ocean and the atmosphere. The ultimate goal of all this work is to better understand the impact of climate change on the environment, resources and human populations in the tropical Atlantic Ocean.