English Summary 
In 1998 the Federal Maritime and Hydrographic Agency (BSH, Bundesamt für Seeschifffahrt 
und Hydrographie) started its annual summer surveys which cover the entire North Sea 
vetween 52° and 60° N. The surveys were realised at a time when thermal stratification is 
expected to be at its maximum and phytoplankton production has passed its maximum (see 
Table 1). The surveys include seven coast to coast East-West sections between 54°and 60° 
N and additional stations between 54° N and the ent rance of the English Channel. With the 
exception of the first survey in 1998 all surveys served a fixed station grid for vertical CTD 
and water samples. Between the fixed CTD-stations a towed CTD-system (1998-2008 the 
BSH system Delphin, since 2009 an EIVA ScanFish MK Il) oscillated between a depth of 3 - 
10 m (depending on weather and sea state) and about 5 metres above the bottom in order to 
record the 3-dimensional distribution of relevant oceanographic parameters. Both CTD- 
systems sampled T, S, fluorescence (chlorophyll-a, yellow substance), and oxygen 
concentration. Additionally, a thermosalinograph and optical sensors were mounted in the 
ship moon pool or drop keel at about 4 m depth. Since 2010 the survey was extended to the 
north in order to record the transition area between the northern North Sea and the eastern 
North Atlantic. 
Additionally, water samples were collected by means of a CTD-rosette sampler-system (e.g. 
for nutrients, salinity, oxygen, pH) and with GoFlow and MERCOS sampler for metals (5 and 
10 m depth). Surface samples for the detection of artificial nuclides were taken at all station. 
Preliminary results: 
The following preliminary results are compiled from ScanFish raw data. Final results will be 
oresented after data reprocessing and post-cruise calibration. 
Temperature 
In 2012 the warm surface layer between 54°and 58° N is colder and thinner compared to the 
10-year average 2000 — 2010 (without 2002). Along the 59°and 60°N sections the thickness 
of the top layer corresponds to the long-term mean but is also cooler. 
Especially the western parts of the sections exhibit a much thinner and cooler top layer. In 
2011 the warm surface water along the UK coast was locally mixed down vertically to 
Dottom. The total heat budget of the North Sea can be calculated not before the reprocessing 
of the CTD data. 
Salinity 
In 2012 the western part of the southern North Sea is fresher than the long-term mean. Both 
inflow regimes of Atlantic water >35 PSU - through the Fair Isle Channel and above the east 
Shetland shelf - are distinguishable north of the 5710 section. 
The Baltic outflow <34 PSU with a depth of about 20 m extends far to the west along the 60° 
section reaching the 0° meridian. Also the salt heat budget can be calculated not until 
detailed analysis after the cruise. 
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