The air and water temperatures remained higher than average and typical of warm years, close to those in 2017. In autumn, the Atlantic waters (>3°С) covered relatively large area, but it decreased compared to 2017; the Arctic and cold bottom waters (<0°С) still covered rather small areas, the area of the former was close to that in 2017 but the area of the latter increased. Ice coverage was much lower than average and close to that in 2017. There was no ice in the sea from August to October; in December, the ice coverage was the lowest since 1951.
In August–September 2018, the area covered by warm water (above 4, 3 and 1°С at 50, 100 m and near the bottom respectively) was close to that in 2017 at 50 and 100 m, and 12% smaller at the bottom (Fig. 3.1.16). The area covered by cold water (below 0°С) was also close to that in 2017 at 50 m but 7 and 8% larger than in 2017 at 100 m and near the bottom respectively (Fig. 3.1.16). Since 2000, the area covered by cold bottom water was the largest in 2003 and rather small in 2007, 2008, 2012, 2016 and 2017; in 2016, it reached a record low value since 1965.
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.
Ice conditions in the Barents Sea in 2018 developed as in low-ice years. In January and February, the ice coverage (expressed as a percentage of the sea area) was respectively 20 and 17% lower than average (1981–2010) and close to that in 2017 (Fig. 3.1.3).
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 showed that positive SST anomalies (relative to the base period of 1982–2010) prevailed in both areas during 2018 (Fig. 3.1.9).
The volume flux into the Barents Sea varies with periods of several years and was significantly lower during 1997–2002 than during 2003–2006 (Fig. 3.1.4). In 2006, the volume flux was at a maximum during winter and very low during fall. After 2006, the inflow has mostly been relatively low. Throughout 2015 and in winter 2016, the inflow was around 1 Sv larger than the long-term average (Fig. 3.1.4). The exception was March 2016, when the volume flux was temporarily smaller than average. The data series presently stops in May 2016, awaiting the processing of measurement data following new instrumentation in the mooring array, thus, no information about the subsequent period is available as of yet.
In 2018, the winter (December–March) NAO index was 0.30 that was much lower than in 2017 (1.47). Over the Barents Sea, southeasterly winds prevailed in January–March 2018 and westerly winds – during the rest of the year. The number of days with winds more than 15 m/s was higher than usual most of the year. It was lower than normal only in the western and central parts of the sea in January and February. In some months (May, June and September in the west of the sea, June and September – in the center as well as April, July and September – in the east), the storm activity was a record high since 1981. For the whole year 2018, it was also a record high in the western (176 days) and central (161 days) Barents Sea.