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 degrees S. Northward propagating anomalies in ocean heat content are found between 5 degrees and 40 degrees 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.