Eight years of continuous Rockall Trough transport observations using moorings and gliders

Abstract. The Rockall Trough (RT) channels an important branch of the North Atlantic Current (NAC), transporting heat from the Gulf Stream toward the Nordic Seas, and the European Slope Current (ESC) which flows northward along its eastern boundary. Variability in the NAC influences poleward heat transport and the strength of the Atlantic Meridional Overturning Circulation, while the ESC plays a key role for the oceanic conditions on the European shelf and the North Sea. Here we present observed volume, heat, and freshwater transports through the Rockall Trough from 2014 to 2022, using data from Ellett Array moorings (operational since 2014) and gliders (deployed from 2020 onward). Although gliders provide high-resolution spatial data in the ESC, their inconsistent temporal coverage complicates their integration into RT transport estimates. We develop a methodology to merge mooring and glider observations into a unified, high-resolution time series, producing—for the first time—a continuous ESC transport dataset spanning nearly a decade. This demonstrates the effectiveness of heterogeneous observing arrays and provides a transferable framework for sustained ocean transport monitoring.