Long-Term Moored Current and Temperature Measurements of the Atlantic Inflow Into the Nordic Seas in the Norwegian Atlantic Current; 1995–2020

Abstract

Interannual variability of the Atlantic inflow (AI) into the Nordic Seas is studied using moored current and temperature measurements in the Norwegian Atlantic Current during the 25-year period 1995–2020. We show that the properties of the AI are strongly connected to the dynamics of the Northern Atlantic and demonstrate the robustness of the average winter wind field in driving the variability with 3-month winter maxima in the range of (40–50) cms−1. In that sense, the zero-wind-stress-curl (ZWSC)-lines aligned northeastward are crucial. Occasional events with slowdown of winter-maxima are connected to a meridional and zonal shift of the ZWSC-lines, and not the strength of the wind. This is manifested in a correlation of 0.3 versus the North Atlantic Oscillation (NAO) winter-index, demonstrating that the NAO-index is insufficient to explain the AI-variability. The records show no long-term-trend over the 25-year period 1995–2020, regarding volume flux, temperature, nor temperature flux.