Atlantic Water flow through Fram Strait to the Arctic Ocean measured by repeated glider transects

Abstract

We present transport estimates of Atlantic Water (AW) and Recirculating Atlantic Water (RAW) across a zonal transect at 77°15′ N using repeated ocean glider observations. Over three missions during autumn and winter of 2020 to 2022, 22 high-resolution sections were collected, enabling detailed characterization of circulation branches and volume transport. On average, the West Spitsbergen Current (WSC) and the Front Current each transport approximately 2.5Sv of AW (Θ>2°C, SA>35.06 g kg-1) northward, yielding a combined net flux of about 5Sv toward the Arctic. Variability in transport and current structure is substantial and appears linked to atmospheric forcing. Case studies reveal that anomalous northward wind stress coincides with peak AW transport, roughly twice the seasonal mean, consistent with Ekman dynamics and elevated sea surface height along the coast. Conversely, strong southward wind stress weakens the WSC and nearly eliminates the Front Current. Transport of RAW (Θ>0°C, SA> 35.06 g kg-1) west of the Front Current is estimated to be about 1Sv, but this does not capture the expected stronger recirculation transport further west, beyond the glider's target transect. These results highlight the capability of gliders to resolve spatial variability in boundary currents that mooring arrays cannot capture. Extended seasonal coverage, including summer, is needed to assess transport variability under peak wind forcing.