scientifique pirata crédit photo : PIRATA / IRD (Institut de Recherche pour le Développement)

After 54 days spent at sea, the PIRATA team is finally back in port in Brest!

This year, 12 scientists and 25 crew members embarked on the 31st mission of the PIRATA oceanographic programme from the port of Brest (France) instead of the usual port since 2015 of Mindelo (Cape Verde), due to the pandemic. Their journey on board the oceanographic vessel Thalassa was therefore extended by 20 days of transit to reach the work area in the tropics, off the Gulf of Guinea. An exceptionally long campaign of 54 days spent at sea, without any stopover!

A Strategic Oceanographic Observatory under the Tropics

The oceans, 97% of which are open water, have a very high capacity to store heat from the atmosphere because water is naturally denser than air. In the tropics in particular, the warmest regions of the world, the ocean is like a huge reservoir of heat and moisture.

The equatorial zone therefore plays a key role in the thermal regulation of our planet. Indeed, it is the ocean, driven by slow-moving currents, that transports and redistributes this heat from the equator to the poles. But its constant interaction with a hot atmosphere subject to fast-moving winds can cause the imbalance of a climate machine that is always ready to run amok!

Monitoring and studying the ocean-atmosphere interaction in the tropical Atlantic Ocean is therefore a necessity. Research should lead to the possibility of predicting increasingly severe and frequent extreme weather events in this region, such as monsoons, tropical cyclones or Atlantic or “El Niño” events with devastating effects on the populations and resources of the Gulf of Guinea countries.

maison africaine ouragan
crédit : T. LEBEL / IRD (Institut de Recherche pour le Développement)

A Permanent Network of Observations of Ocean-Climate Interactions

It was in this context that the experimental oceanography programme PIRATA (acronym for ‘Prediction and Research Moored Array in the Tropical Atlantic’) was conceived in 1995, based on an international collaboration between France, Brazil and the USA.

PIRATA was born out of the need to collect long-term oceanic and atmospheric data in the tropical Atlantic Ocean. Since the 1990s, some spot measurements have been made in this area along trade routes, from merchant ships and research vessels. PIRATA complements these measurements by allowing the establishment of a permanent monitoring network installed in the open ocean, with fixed measurements.

Once again this year, during this 31st PIRATA mission and within a logistic context complicated by the health situation, the maintenance of this complete observation network was ensured.

For nearly 24 years, the collection of these data has led to major scientific advances. Each year, the PIRATA campaigns contribute to a better understanding of the dynamics of ocean currents in the equatorial zone. Scientists are also gaining a better understanding of the interactions between the ocean and the atmosphere in this region, and the role of each in the climate system. Year after year, the impact of global warming on the ocean or the role of the ocean in cyclones, extreme events in the Brazilian Northeast and the African monsoon are being assessed across the tropical Atlantic.

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