The Barents Sea has become substantial colder since 2015–2016. However, its air and water temperatures in 2020 were generally higher than long-term average, being typical of warm year. In autumn, the areas covered by Atlantic (>3°С) and Arctic (<0°С) waters changed insignificantly compared to 2019; while the area covered by cold bottom waters (<0°С) increased and turned out to be the largest since 2011. Ice coverage of the Barents Sea has increased since 2016 due to lower temperatures and lower inflow of Atlantic Water, but the ice coverage in 2020 was still below average. There was almost no ice in the sea from August to November. In November, the ice coverage reached a record-low value of 3% since 1951.
Meteorological and oceanographic conditions 2020
In 2020, the winter (December–March) NAO index was 1.78 that was much higher than in 2019 (0.74) and reached the fourth maximum since 1900 (after 1989 – 2.43, 1990 – 1.91 and 2015 – 1.83). Over the Barents Sea, the number of days with winds more than 15 m/s was higher than or close to the long-term mean (1981–2010) all over the year, with the largest anomaly in March. The storm activity was a record high (since 1981) in the western part of the sea in January, April and November, in the eastern part in March and April, and in the central part in March. For the whole year 2020, it was also a record high in the western Barents Sea (181 days) and reached the second highest value in the central (157 days) and eastern (165 days) parts of the sea.
Sea surface temperature (SST) (http://iridl.ldeo.columbia.edu) averaged over the southwestern (71–74°N, 20–40°E) and southeastern (69–73°N, 42–55°E) Barents Sea exceeded the long-term mean (1982–2010) throughout 2020 (Fig. 3.1.7). Small positive anomalies (0.1–0.3°С) were found in the southwestern part of the sea in the first half of the year and large ones (1.1–3.2°С) were observed in the southeastern part in the second half of the year.
The volume flux into the Barents Sea varies with periods of several years. The annual volume flux was relatively high during 2003–2006 (Fig. 3.1.4a). From 2006 to 2014, the inflow was relatively stable before it increased substantially in 2015 to about 1 Sv above the long-term average. The year of 2016 had relatively low inflow. Since 2017 the annual volume inflow to the Barents Sea has decreased (Fig. 3.1.4a). There is no statistically significant trend in the annual volume fluxes
From January to April 2020, the Barents Sea ice extent (expressed as a percentage of the total sea area) was slightly (by 3–7%) less than the long-term means (1981–2010) (Fig. 3.1.3). However, in May, intensive ice melting started, and by August, the sea was completely free of ice.
Focusing on different depths, the area covered by warm water (above 4, 3 and 1°С at 50, 100 m and near the bottom, respectively) in August–October 2020 was close to that in 2019 (Fig. 3.1.14). The area covered by cold water (below 0°С) was 3 and 6% larger than in 2019 at 50 m and near the bottom, respectively, but 3% smaller – at 100 m.
The Fugløya–Bear Island Section 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 Section 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.
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.