Active Pacific meridional overturning circulation (PMOC) during the warm Pliocene
Yale University and LOCEAN
Jeudi 19/03/2020, 11:00-12:00
Bât. 714, P. 1129, LSCE Orme des Merisiers
An essential element of modern ocean circulation and climate is the Atlantic meridional overturning circulation (AMOC), which includes deep-water formation in the subarctic North Atlantic. A comparable overturning circulation is, however, absent in the Pacific, the world’s largest ocean, where relatively fresh surface waters inhibit North Pacific deep convection. Here I present climate modeling simulations and complementary paleo measurements showing that the warm, elevated CO2 world of the Pliocene may have supported North Pacific deep-water formation and a strong Pacific meridional overturning circulation (PMOC) cell. We find that atmospheric moisture transport changes, in response to the reduced meridional sea surface temperature gradients of the Pliocene, were capable of eroding the fresh halocline, leading to active deep-water formation in the western subarctic Pacific. The Pacific overturning cell has important implications for global ocean circulation and heat transports during the Pliocene.