Cruise Report, RV ATAIR, Cruise 0671021-1, Bremerhaven - Thyboron - Aberdeen, 18 Jul —- 10 Aug 2023 | 33 
and a local minimum with S < 30 directly south of Norway. Surface salinity deviations of sum- 
mer 2023 from the long-term mean field point to the North Sea having been divided into a 
fresher half in the south and southwest and a more saline half in the east to northeast (Figure 
6.5, right). 
Salintvy at the bottom 
50°N 
90 
56° 
4° 
399 4 
50° + . 
6°W A4d4° 
„2° 0° 
0 
4° 
‘VAtair 
"ruise 06710121-1 
'8 Jul - 10 Aug 2023 
3remerhaven - Aberdee, 
BR 8° 
Salinty at the bottom minus mean (2000-2020) 
60°N 
58° 
56° 
54° 
52° 
ZV Atalr 
Cruise 06710121-1 
‘8 Jul - 10 Aug 2023 
Zremerhayen - Aherdaser 
+ 50° = 
10°E 6°W Ad° 
0 
0° 
„0 
A° 
A° 
FF  — 
8° 10°E 
Figure 6.6. CTD-derived spatial distribution for the salinity near the sea bottom in summer 2023 (left) 
and respective salinity deviations (right) from a long-term mean, 20 years, comprising NSSS cruises the 
years 2000-2020 (except 2019). 
Regarding the bottom layer (Figure 6.6, left), salinity > 35 fills most of the North Sea bottom 
regions near 58°N and to the north of it and reaches as far south as 56°N in the central part of 
the North Sea. Highest salinities (S > 35.2) appear along 60°N, near Shetland and near the 
western edge of the Norwegian Trench. Salinity as high as 34.5 spreading from the north is 
observed until 54°N. A local maximum with S = 34.60 north of the River Thames outlet points 
to traces of saline water entering the North Sea via the English Channel. Due to missing data 
in the English Channel south of 52°N, this signal cannot be further explored. Fresh salinity < 
32 stretches along the western German and Danish coasts clearly pointing to the impact of 
freshwater runoff coming from continental rivers like Elbe or Weser. Bottom salinity deviations 
af summer 2023 from the long-term mean field show a freshening in the English Channel and 
off Jütland as well as more saline conditions near the outlet of the Elbe River. 
Figures 6.7 and 6.8 present temperature and salinity along coast-to-coast sections following 
the latitudes 60°N, 58°N, 57°N, 56°N, 55°N and 54°N. Due to the varying water depths from 
the deep northern North Sea to the shallow southern North Sea, the lower part of the water 
solumn is typically colder in the north. The water column is typically more homogeneous in the 
south and becomes increasingly stratified in temperature towards the north. The input of At- 
lantic Water across the northern boundaries of the North Sea and its subsequent propagation