EXCEPTIONALLY STRONG WARMING OF EQUATORIAL ATLANTIC UPPER INTERMEDIATE WATERS DURING YOUNGER DRYAS: THE ROLE OF OCEANIC-ATMOSPHERIC FEEDBACK PROCESSES IN THE TROPICS

Here we present a 20,000-year-long temperature record of the upper intermediate waters of the western equatorial Atlantic. One of the most outstanding features of the record is an exceptionally strong and abrupt warming (by up to 5.5±0.9°C within a century) during the Younger Dryas (12,900-11,700 years ago), an episode of freshwater-induced climate perturbations with a substantial cooling of North and South Atlantic intermediate and deep-sea waters. The rate and magnitude of the tropical Atlantic intermediate water warming is unmatched by those of the radiative forcings associated with the rise of three main greenhouse gases (CH₄, CO₂, and N₂O. This observation emphasizes oceanic-atmospheric feedback processes in the tropical-subtropical ocean that most likely led to anomalously large warming of the tropical upper intermediate waters.