Cruise Report, RV ATAIR, Cruise 0671021-1, Bremerhaven - Thyboron —- Aberdeen, 18 Jul - 10 Aug 2023 | 29

6.

Oceanographic Conditions in Summer 2023

The BSH produces and provides a comprehensive weekly analysis of sea surface temperatures
 (see  https:/www.bsh.de/EN/DATA/Climate-and-Sea/Sea_temperatures/Sea_surface_temperatures/sea_surface_temperatures_node.html).
 This approach combines all measurements
 collected from time series stations and ships with satellite data and uses statistical
methods and spatial interpolation to generate a comprehensive data set. This contains estimates
 for the weekly mean values of sea surface temperature as a raster data set with a spatial
resolution (pixel size) of 20 km x 20 km.

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1.5

57°N

54°N

S

1

S

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7

-0.5

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7

1.5

51°N

3°W

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66°E

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Figure 6.1. Spatial distribution of sea surface temperature (SST) anomalies for the summer of 2023
(June, July and August). Anomalies are shown relative to a climatological mean SST field comprising
the summers of the years 1997-2021, ie. 25 years. Source: BSH.

Information from this blended analysis SST analysis for the summer months of 2023 (June,
July and August) reveals a region of pronounced warming in the western North Sea (Figure
5.1). The centre of this region was located at about 56°30’N off the British east coast and
stretched from about 55°N towards the Orkney and Shetland Islands in the north. There, SSTs
were about 0.75°C to 1.5°C warmer than the 1997-2021 climatological summer mean. Elevated
 surface warming (SST anomalies > 0.75°C) was also noteable west and north of the
Dogger Bank as well as above it. The coastal regions surrounding the German Bight in the
south and east did not show a comparable warming but rather normal conditions. The region
af the Norwegian Trench off southern Norways was cooler than the climatological summer
mean (- -0.75°C).