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

Temperature sampling equipment. Photo: Norwegian Polar Institute

Meteorological and oceanographic conditions 2018
Typography
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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 showed that positive SST anomalies (relative to the base period of 1982–2010) prevailed in both areas during 2018 (Fig. 3.1.9).

The largest positive anomalies (>2.0°C) were found in the southeast of the sea in July–September; the December SST anomaly in this area reached a record high value since 1982. The smallest positive anomalies (<0.5°C) were observed in the southwest of the sea in April, May and July, and in the southeast from March to June (Fig. 3.1.9).


Figure 3.1.9. Sea surface temperature anomalies in the western (upper) and eastern (lower) Barents Sea in 1985–2018. The blue line shows monthly values, the black one – 11-month running means. Figure 3.1.9. Sea surface temperature anomalies in the western (upper) and eastern (lower) Barents Sea in 1985–2018. The blue line shows monthly values, the black one – 11-month running means.

During August–September 2018, the joint Norwegian-Russian ecosystem survey was carried out in the Barents Sea. Surface temperature was on average 1.0°C higher than the long-term (1931–2010) mean in most of the sea (Fig. 3.1.10). The largest positive anomalies (>2.0°C) were mainly observed in the southeastern part of the Barents Sea as well as west and north of the Spitsbergen Archipelago. Small negative anomalies took place mostly in some areas in the southwest of the sea. Compared to 2017, the surface temperature was higher (by 1.0°C on average) in southern and northern parts of the surveyed area, especially north of the Spitsbergen Archipelago, and lower (by 0.7°C on average) – in the western and central parts, especially west of the Spitsbergen Archipelago (Fig. 3.1.10).


Figure 3.1.10. Surface temperatures (°C) in August–September 2017 (upper left) and 2018 (upper right), their differences between 2018 and 2017 (lower left, °C) and anomalies in August–September 2018 (lower right, °C). Figure 3.1.10. Surface temperatures (°C) in August–September 2017 (upper left) and 2018 (upper right), their differences between 2018 and 2017 (lower left, °C) and anomalies in August–September 2018 (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 most of the Barents Sea (Fig. 3.1.11). Small negative anomalies were mainly found at 100 m depth in some small areas in the northern part of the surveyed area. Compared to 2017, the 50 m temperature was on average 0.9°C higher in about two thirds of the surveyed area with the largest differences in the northernmost Barents Sea; negative temperature differences (on average –0.6°C) prevailed in the west of the sea. The 100 m temperature was on average 0.4°C lower than in 2017 in about half the surveyed area, especially in its western and eastern parts (Fig. 3.1.11). In the rest area, waters at 100 m were on average 0.4°C warmer compared to 2017 with the largest positive differences east of the Spitsbergen Archipelago.


Figure 3.1.11. 100 m temperatures (°C) in August–September 2017 (upper left) and 2018 (upper right), their differences between 2018 and 2017 (lower left, °C) and anomalies in August–September 2018 (lower right, °C). Figure 3.1.11. 100 m temperatures (°C) in August–September 2017 (upper left) and 2018 (upper right), their differences between 2018 and 2017 (lower left, °C) and anomalies in August–September 2018 (lower right, °C).

Bottom temperature was in general 0.8°C above average (1931–2010) in most of the Barents Sea (Fig. 3.1.12). Negative anomalies (–0.4°C on average) were only observed east of the Spitsbergen Archipelago. Compared to 2017, the bottom temperature was on average 0.4°C lower in two thirds of the surveyed area (Fig. 3.1.12). Bottom waters were warmer (on average, by 0.6°C) than in 2017 mainly in the northern sea, especially east of the Spitsbergen Archipelago.


Figure 3.1.12. Bottom temperatures (°C) in August–September 2017 (upper left) and 2018 (upper right), their differences between 2018 and 2017 (lower left, °C) and anomalies in August–September 2018 (lower right, °C). Figure 3.1.12. Bottom temperatures (°C) in August–September 2017 (upper left) and 2018 (upper right), their differences between 2018 and 2017 (lower left, °C) and anomalies in August–September 2018 (lower right, °C).

Surface salinity was on average 0.5 higher than the long-term mean (1931–2010) in most of the Barents Sea with the largest positive anomalies (>0.8) in its northern part; at the same time the positive anomalies decreased southwards (Fig. 3.1.13). Negative anomalies (–0.1 on average) were mainly observed in the southernmost and southwestern parts of the Barents Sea. Compared to 2017, the surface waters were on average 0.5 saltier in two thirds of the surveyed area with the largest positive differences in the northern part of the sea and north of the Spitsbergen Archipelago (Fig. 3.1.13). Negative differences in salinity between 2018 and 2017 (–0.1 and more) were found in the central, northeastern, western and southwestern parts of the Barents Sea.

 


Figure 3.1.13. Surface salinities in August–September 2017 (upper left) and 2018 (upper right), their differences between 2018 and 2017 (lower left) and anomalies in August–September 2018 (lower right). Figure 3.1.13. Surface salinities in August–September 2017 (upper left) and 2018 (upper right), their differences between 2018 and 2017 (lower left) and anomalies in August–September 2018 (lower right).

The 100 m salinity was, in general, close to both the average (1931–2010) and that in 2017 in most of the Barents Sea (Fig. 3.1.14). Significant negative anomalies and differences between 2018 and 2017 (–0.1 and more) were mainly observed in the coastal waters in the southwestern and southern parts of the Barents Sea, and significant positive anomalies and differences (>0.1) – in the northwest of the sea, especially east of the Spitsbergen Archipelago (Fig. 3.1.14).

 


Figure 3.1.14. 100 m salinities in August–September 2017 (upper left) and 2018 (upper right), their differences between 2018 and 2017 (lower left) and anomalies in August–September 2018 (lower right). Figure 3.1.14. 100 m salinities in August–September 2017 (upper left) and 2018 (upper right), their differences between 2018 and 2017 (lower left) and anomalies in August–September 2018 (lower right).

Bottom salinity was close to both the average (1931–2010) and that in 2017 in most of the Barents Sea (Fig. 3.1.15). Positive salinity anomalies of higher than 0.1 took place in shallow waters over the Spitsbergen Bank, and significant negative anomalies were mainly found in the coastal waters in the southwestern and southern parts of the Barents Sea and in shallow waters east of the Spitsbergen Archipelago. Significant differences in bottom salinity between 2018 and 2017 were mainly found in the area between the Spitsbergen Archipelago and Bear Island, where the bottom waters in 2018 were fresher (by 0.1 and more) compared to 2017 (Fig. 3.1.15).

 


Figure 3.1.15. Bottom salinities in August–September 2017 (upper left) and 2018 (upper right), their differences between 2018 and 2017 (lower left) and anomalies in August–September 2018 (lower right). Figure 3.1.15. Bottom salinities in August–September 2017 (upper left) and 2018 (upper right), their differences between 2018 and 2017 (lower left) and anomalies in August–September 2018 (lower right).

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