Dynamics of the Polar Front in the southwestern area of Svalbard, Norway

Abstract

We have investigated the dynamics of the Polar Front (PF) in the southwestern area of Svalbard, where the dynamics are defined by the interaction between the Sørkapp Current (transporting cold and fresh Arctic-type water) and the West Spitsbergen Current (carrying the warmer and more saline Atlantic Water from the Norwegian Sea). Our approach was based on the global circulation model predictions. In accord with the model, the cold and fresher Arctic water masses originated from the eastern side of Svalbard and were flowing along the southern-most point of Svalbard into the southwestern area of Svalbard. This cold and fresher water was spreading and pushing warmer and more saline Atlantic water offshore. The model currents indicated that cold and fresher water masses were mostly transported northward along the south-western coast of Svalbard. In accord with the model and observed density profiles, the PF is a density compensated front with the density gradient mostly in the top 50-75 m. Presence of strong density gradients in the upper 50-75 m of the PF leads to the development of the submesoscale processes as surface frontogenesis and nonlinear Ekman transport. We found strong presence of surface frontogenesis at the PF in the model. The second submesoscale process, the nonlinear Ekman transport, is due to the forcing interaction. During the considered time frame, the winds were blowing mostly from the north-east to south-west across the PF, and therefore, the along-front wind component was very small, resulting in weak non-linear Ekman transport at the PF front.