Variability of the Polar Front Characteristics in the Northwestern Barents Sea Based on In-Situ Observations from 2017 to 2023

This study presents oceanographic observations from the R/V Dalnie Zelentsy along the Kola Section (2017–2023), focusing on the northern Polar Front during autumn, winter, and spring. Sea ice anomalies were estimated using data from the World Data Center for Sea Ice (AARI WDC Sea-Ice). Observational data near the Marginal Ice Zone were compared with temperature and salinity fields from global oceanographic datasets, including MERCATOR PSY4QV3R1, CMEMS GLORYS12v1, and TOPAZ5. High-gradient temperature and salinity zones were observed at varying distances from the ice edge along all sections. Over the past three decades, the western Barents Sea has experienced a steady decline in sea ice cover. The northernmost Polar Front along the Kola Section ranged from 48 to 290 km from the ice edge, with temperature gradients of 0.10–0.20 °C/km and salinity gradients of 0.012–0.025 psu/km. The frontal zone width did not exceed 55 km. Among the assessed data products, MERCATOR PSY- 4QV3R1 showed the highest correlation with in situ measurements.