Spatial variation in temperature and salinity (surface, 100 m and bottom)

Spatial variation in temperature and salinity (surface, 100 m and bottom)

In the southwest, the largest anomalies (>1.0°С) were found in August–October; and in the southeast, anomalies of more than 1.5°C were observed in July–October (Fig. 3.1.7). From January to May 2020, the SST was lower than or close to that in 2019; but in the rest of the year (from June to December), it exceeded the values of the previous year significantly (by 0.6–3.0°С) (Fig. 3.1.7).

Figure 3.1.7. Annual (upper) and monthly (lower) sea surface temperature anomalies in the western and eastern Barents Sea.

In August–October 2020, the joint Norwegian-Russian ecosystem survey was carried out in the Barents Sea. Surface temperature was on average 1.4°C higher than the long-term mean (1981–2010) in almost all over the surveyed area (95%) (Fig. 3.1.8). Positive anomalies increased eastwards and reached more than 3°C in the southeastern Barents Sea. Negative anomalies (about −0.7°C on average) were only found in a small area south of Bear Island. Compared to 2019, the surface temperature in 2020 was much higher (by 1.4°C on average) in most of the surveyed area (~80%), with the largest positive differences (>3°C) in the southeastern and southwesternmost parts of the sea (Fig. 3.1.8). Negative differences in temperature between 2020 and 2019 were mainly found in the western Barents Sea between 73 and 76°N as well as over the Murman Rise.

Figure 3.1.8. Surface temperatures (°C) in August–October 2019 (upper left) and 2020 (upper right), their differences between 2020 and 2019 (lower left, °C) and anomalies in August–October 2020 (lower right, °C).

Arctic waters were mainly found, as usual, in the 50–100 m layer north of 77°N. Temperatures at depths of 50 and 100 m were higher than the long-term means (1981–2010) (on average, by 0.7 and 0.5°C, respectively) in about two thirds of the surveyed area with the largest positive anomalies in the southeast, especially at 50 m depth (Fig. 3.1.9). Negative anomalies (about −0.4°C on average) were mostly found over the Great Bank and in some areas in the central Barents Sea. Compared to 2019, the 50 and 100 m temperatures in 2020 were lower (on average, by 1.0 and 0.5°C, respectively) in half of the surveyed area, especially in the central and southeastern parts of the sea; positive differences were mainly observed in the southwestern Barents Sea as well as south and east of the Spitsbergen Archipelago (Fig. 3.1.9).

Figure 3.1.9. 100 m temperatures (°C) in August–October 2019 (upper left) and 2020 (upper right), their differences between 2020 and 2019 (lower left, °C) and anomalies in August–October 2020 (lower right, °C).

Bottom temperature was generally 0.7°C above the long-term mean (1981–2010) in two thirds of the surveyed area with the largest positive anomalies in the south-eastern Barents Sea (Fig. 3.1.10). Negative anomalies (−0.5°C on average) were mainly found in some areas in the southern and northern parts of the sea with the largest values east of the Spitsbergen Archipelago and over the Great Bank. Compared to 2019, the bottom temperature in 2020 was on average 0.5°C lower in 60% of the surveyed area with the largest differences over the North Kanin Bank and in the Eastern Basin (Fig. 3.1.10). Bottom waters were warmer (on average, by 0.5°C) than in 2019 mainly in the western part of the sea, east of the Spitsbergen Archipelago and in a small area north of Kanin Peninsula.

Figure 3.1.10. Bottom temperatures (°C) in August–October 2019 (upper left) and 2020 (upper right), their differences between 2020 and 2019 (lower left, °C) and anomalies in August–October 2020 (lower right, °C).

Surface salinity was on average 0.3 higher than the long-term mean (1981–2010) in about 40% of the surveyed area with the largest positive anomalies (>0.4) in the north and southeast of the Barents Sea (Fig. 3.1.11). Negative anomalies (–0.15 on average) were observed in the western and central parts of the sea as well as in a small area north of Kanin Peninsula. In August–October 2020, surface waters were on average 0.2 fresher than in 2019 in about 60% of the surveyed area; they were saltier (on average, by 0.4) mainly east of the Spitsbergen Archipelago and in the southeastern Barents Sea (Fig. 3.1.11).

Figure 3.1.11. Surface salinities in August–October 2019 (upper left) and 2020 (upper right), their differences between 2020 and 2019 (lower left) and anomalies in August–October 2020 (lower right). Salinity of deeper waters was lower than average (1981–2010) (by 0.1 on average) in about half of the surveyed area at 50 m depth and almost all over the sea (80% of the area) at 100 m depth with the largest negative anomalies in coastal waters in the southwestern Barents Sea (Fig. 3.1.12). Positive anomalies were found in the northern, especially east of the Spitsbergen Archipelago, and south-eastern parts of the sea. In August–October 2020, waters at 50 and 100 m were fresher (by 0.1 on average) than in 2019 in most of the surveyed area (57 and 65%, respectively) with the largest negative differences east of the Spitsbergen Archipelago and in coastal waters in the southwestern Barents Sea (Fig. 3.1.12). Significant positive differences (>0.1) in salinity between 2020 and 2019 were mainly observed in the south-eastern Barents Sea. At a depth of 50 m, both anomalies and differences were larger than at 100 m. At a depth of 100 m, salinity anomalies and differences of

Figure 3.1.12. 100 m salinities in August–October 2019 (upper left) and 2020 (upper right), their differences between 2020 and 2019 (lower left) and anomalies in August–October 2020 (lower right).

Bottom salinity was slightly lower than average (1981–2010) in about 80% of the surveyed area with the largest negative anomalies (>0.1 in magnitude) mainly in coastal waters in the southwestern Barents Sea and east of Bear Island (Fig. 3.1.13). Positive anomalies were found in the south-eastern part of the sea and in some areas around the Spitsbergen Archipelago. In August–October 2020, the bottom waters were a bit fresher than in 2019 in three fourths of the surveyed area (Fig. 3.1.13). Only in the south-eastern Barents Sea, they were much saltier compared to 2019. As a whole, bottom salinity anomalies and differences were small (

Figure 3.1.13. Bottom salinities in August–October 2019 (upper left) and 2020 (upper right), their differences between 2020 and 2019 (lower left) and anomalies in August–October 2020 (lower right).