Southern Ocean Origin of Multidecadal Variability in the North Brazil Current

Analysis of model data from a long (200 years) simulation of a high-resolution version of the Parallel Ocean Program indicates a connection between a mode of multidecadal variability in the Southern Ocean, the so-called Southern Ocean Mode, and multidecadal variability in the North Brazil Current. The multidecadal sea surface height variability in the Southern Ocean propagates northward and submerges at about 40°S. Northward propagating anomalies in ocean heat content are found between 5° and 40°S at depths down to 1 km and affect the North Brazil Current. Similar variability and connections between Southern Ocean and North Brazil Current are also found in a (200 years) simulation of a high-resolution global version of the Community Earth System Model. The results provide a new mechanism for the low-frequency variability of the North Brazil Current.