Seasonal circulation and volume transport of the Bransfield Current

•The Bransfield Current is a year-round surface-intensified coastal jet.•The current has two distinct regions: upstream and downstream Nelson Strait.•Upstream, the jet transport is largest (lowest) during summer (winter) at 0.93 Sv (0.50 Sv).•Downstream, the jet transport exhibits no seasonal variability (1.31 Sv).•A mass balance analysis supports an inflow through Nelson Strait feeds the jet recurrently.