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

Photo: Lawrence Hislop, Norwegian Polar Institute.

Meteorological and oceanographical conditions 2019
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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 dropped significantly in 2019 compared to the previous year and its annual mean value was the lowest since 2011 (Fig. 3.1.7). The SST in the southwestern part of the sea was close to the long-term average (1982–2010) for most of the year; small negative anomalies of −0.2, −0.3 and −0.1°С were found in July, August and November respectively; positive anomalies of more than 0.5°C were only observed in January, February and September.

The SST in the southeastern part of the sea exceeded the average for most of the year and was close to it only in June, July, November and December; while July and November anomalies were slightly negative (−0.1 and −0.2°С respectively). In the southeast, the largest positive anomalies (>0.8°C) were observed in January, April, May and September (Fig. 3.1.7).

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

During August–September 2019, the joint Norwegian-Russian ecosystem survey was carried out in the Barents Sea. Surface temperature was on average 0.7°C higher than the long-term (1931–2010) mean in about two thirds of the surveyed area (Fig. 3.1.8). Negative anomalies (about −0.5°C on average) took place mostly in the northernmost and south-western Barents Sea. Compared to 2018, the surface temperature in 2019 was much lower (by 1.1°C on average) in most of the surveyed area (~80%), with the largest negative differences (>2°C) in the south-eastern and south-westernmost parts of the sea as well as north and east of the Spitsbergen Archipelago (Fig. 3.1.8). 

Figure 3.1.8. Surface temperatures (°C) in August–September 2018 (upper left) and 2019 (upper right), their differences between 2019 and 2018 (lower left, °C) and anomalies in August–September 2019 (lower right, °C).= Figure 3.1.8. Surface temperatures (°C) in August–September 2018 (upper left) and 2019 (upper right), their differences between 2019 and 2018 (lower left, °C) and anomalies in August–September 2019 (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 (1931–2010) means (on average, by 1.1 and 0.7°C respectively) in about two thirds of the surveyed area with the largest positive anomalies in the east, especially at 50 m depth (Fig. 3.1.9). Negative anomalies (about −0.4°C on average) were mainly found in the northern and south-western Barents Sea with the largest values in the north at a depth of 100 m. Compared to 2018, the 50 and 100 m temperatures in 2019 were lower (on average, by 0.9 and 0.7°C respectively) in most of the surveyed area (80 and 85% respectively) with the largest negative differences in the northern Barents Sea at 50 m depth; positive differences were mainly observed in the south-eastern part of the sea (Fig. 3.1.9).

Figure 3.1.9. 100 m temperatures (°C) in August–September 2018 (upper left) and 2019 (upper right), their differences between 2019 and 2018 (lower left, °C) and anomalies in August–September 2019 (lower right, °C).Figure 3.1.9. 100 m temperatures (°C) in August–September 2018 (upper left) and 2019 (upper right), their differences between 2019 and 2018 (lower left, °C) and anomalies in August–September 2019 (lower right, °C).

Bottom temperature was in general 0.8°C above average (1931–2010) in most of the Barents Sea (~70% of the surveyed area) with the largest positive anomalies in the south-east (Fig. 3.1.10). Negative anomalies (−0.8°C on average) were mainly observed in the northern part of the sea with the largest values east of the Spitsbergen Archipelago. Compared to 2018, the bottom temperature in 2019 was on average 0.7°C lower in 75% of the surveyed area with the largest differences in the north (Fig. 3.1.10). Bottom waters were warmer (on average, by 0.5°C) than in 2018 mainly in the south-eastern part of the sea.

Figure 3.1.10. Bottom temperatures (°C) in August–September 2018 (upper left) and 2019 (upper right), their differences between 2019 and 2018 (lower left, °C) and anomalies in August–September 2019 (lower right, °C).t Figure 3.1.10. Bottom temperatures (°C) in August–September 2018 (upper left) and 2019 (upper right), their differences between 2019 and 2018 (lower left, °C) and anomalies in August–September 2019 (lower right, °C).

Surface salinity was on average 0.3 higher than the long-term (1931–2010) mean mainly in the central and northern parts of the surveyed area with the largest positive anomalies (>0.8) mostly in the northern Barents Sea (Fig. 3.1.11). Negative anomalies (about −0.3 on average) were mainly observed in the western, southern and south-eastern parts of the sea with the largest values in some areas in the south-east. In August–September 2019, the surface waters were on average 0.4 fresher than in 2018 almost all over the surveyed area (87%) with the largest negative differences east of the Spitsbergen Archipelago and in the south-eastern Barents Sea (Fig. 3.1.11).

Figure 3.1.11. Surface salinities in August–September 2018 (upper left) and 2019 (upper right), their differences between 2019 and 2018 (lower left) and anomalies in August–September 2019 (lower right). Figure 3.1.11. Surface salinities in August–September 2018 (upper left) and 2019 (upper right), their differences between 2019 and 2018 (lower left) and anomalies in August–September 2019 (lower right).

The 50 and 100 m salinity was lower than average (1931–2010) (by about 0.1 on average) in two thirds of the surveyed area with the largest negative anomalies in the south-eastern part of the Barents Sea (Fig. 3.1.12). Positive anomalies were mainly observed in the north-western part of the sea with the largest values east of the Spitsbergen Archipelago. In August–September 2019, waters at 50 and 100 m were fresher (by 0.1 on average) than in 2018 in most of the surveyed area (58 and 67% respectively) with the largest negative differences in the east of the area (Fig. 3.1.12). Significant positive differences (>0.1) in salinity between 2019 and 2018 were mainly observed in the northern Barents Sea and in the coastal waters of its south-western part. At a depth of 100 m, salinity anomalies and differences of less than 0.1 occupied about 80 and 90% of the surveyed area respectively (Fig. 3.1.12).

Figure 3.1.12. 100 m salinities in August–September 2018 (upper left) and 2019 (upper right), their differences between 2019 and 2018 (lower left) and anomalies in August–September 2019 (lower right). Figure 3.1.12. 100 m salinities in August–September 2018 (upper left) and 2019 (upper right), their differences between 2019 and 2018 (lower left) and anomalies in August–September 2019 (lower right).

Bottom salinity was slightly lower than average (1931–2010) in two thirds of the surveyed area with the largest negative anomalies (>0.1) in the south-eastern and northernmost Barents Sea (Fig. 3.1.13). Slightly positive anomalies were found in the central part of the sea and anomalies of more than 0.1 took place mainly south and south-east of the Spitsbergen Archipelago as well as in shallow waters in the south-easternmost part of the sea. In August–September 2019, the bottom waters were a bit fresher than in 2018 in most of the surveyed area (80%) (Fig. 3.1.13). The largest negative differences (>0.1) in bottom salinity between 2019 and 2018 were mostly found in small areas north of the White Sea Opening and Kanin Peninsula as well as north of Bear Island. Only coastal waters in the south-western Barents Sea and waters around the Spitsbergen Archipelago were saltier than in 2018. As a whole, bottom salinity anomalies and differences were small (<0.1) almost all over the surveyed area (78 and 86% respectively) (Fig. 3.1.13).

Figure 3.1.13. Bottom salinities in August–September 2018 (upper left) and 2019 (upper right), their differences between 2019 and 2018 (lower left) and anomalies in August–September 2019 (lower right). Figure 3.1.13. Bottom salinities in August–September 2018 (upper left) and 2019 (upper right), their differences between 2019 and 2018 (lower left) and anomalies in August–September 2019 (lower right).

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