The Fugløya–Bear Island and Vardø-North Sections covers the inflow of Atlantic and Coastal water masses from the Norwegian Sea to the Barents Sea, while the Kola Section covers the same waters in the southern Barents Sea. Note a difference in the calculation of the temperatures in these sections; in the Fugløya–Bear Island and Vardø-North Sections the temperature is averaged over the 50–200 m depth layer while in the Kola Section the temperature is averaged from 0 to 200 m depth.
Temperature and salinity in standard sections and northern boundary regions
During 2015–2019, the temperatures in the inflowing Atlantic Water to the Barents Sea decreased by more than 1°C (Fig. 3.1.5). The decrease in the Atlantic Water temperatures are linked to lower temperatures upstream in the Norwegian Sea. However, in 2020, the temperatures increased slightly as compared to 2019, seemingly linked to the higher inflow during winter. At the Fugløya–Bear Island Section, which is in the far western entrance, the temperatures of the inflowing Atlantic Water was in 2020 about 0.2°C above the long term average (1981–2010), while the Vardø–North Section showed anomalies approaching 0.7°C.
The salinity of the inflowing Atlantic Water has decreased since 2011 (Fig. 3.1.5). The salinity at the Fugløya–Bear Island Section was slightly higher in 2020 as compared to 2019, which again can be linked to stronger inflow during winter, while the salinity anomaly at the Vardø–North Section continued to decline also in 2020.
Figure 3.1.5. Average temperature (left) and salinity (right) in August–September in the 50–200 m layer in the Fugløya–Bear Island and Vardø–North Sections. Black lines show annual August–September values, while thick coloured lines show three years running means. Horizontal lines show average over the period 1981–2010.Temperature of coastal and Atlantic waters in the Kola Section in 2020 was above the long-term mean (1981–2010) and generally typical of warm years. During the 2020 observation period, positive temperature anomalies in Atlantic waters (0–200 m) varied insignificantly; anomalies averaged over January–September were 0.3 and 0.4°C in the central (Murman Current) and outer (Central branch of the North Cape Current) parts of the section, respectively (Fig. 3.1.6). Anomalies in coastal waters were significantly higher and increased from 0.7°С in August to 1.1°С in November. The 2020 annual mean temperature of Atlantic waters (0–200 m) in the Kola Section (central part) was typical of warm years and exceeded the 1981–2010 average by 0.3°C, being 0.1°C lower than in 2019 (Fig. 3.1.6).
Salinity of coastal and Atlantic waters in the Kola Section in 2020 was lower than average (1981–2010). During the 2020 observation period, negative salinity anomalies in Atlantic waters (0–200 m) varied insignificantly; anomalies averaged over January–September were −0.04 and −0.08 in the central (Murman Current) and outer (Central branch of the North Cape Current) parts of the section, respectively (Fig. 3.1.6). Anomalies in coastal waters varied from −0.01 in August to −0.17 in November. The 2020 annual mean salinity of Atlantic waters (0–200 m) in the Kola Section (central part) was 0.04 lower than average but 0.03 higher than in 2019 (Fig. 3.1.6).
Figure 3.1.6. Monthly and annual temperature and salinity anomalies in the 0–200 m layer in the Kola Section. St. 1–3 – Coastal waters, St. 3–7 – Murman Current, St. 8–10 – Central branch of the North Cape Current (Anon., 2021). Annual mean values for 2016–2020 were recovered.