Bussmann, Ingeborg; Brix, Holger; Fischer, Philipp; Flöser, Götz; Geißler, Felix (2023): MOSES Sternfahrt-5, Spatial extension of the riverine influence of Elbe and Weser into the southern North Sea (German Bight) in 2020 [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.962691

The southern North Sea (German Bight) is influenced by the inflowing water in the Tide-Elbe area and how it is further modified. For a better understanding of the different branches of relevant events it is necessary to investigate which are the main impacting factors for the terrestrial and coastal water quality. Therefore, during different cruises between 2019 and 2022 a group of parameters was continuously traced from the Elbe River basin (Czech/German border) to Tide-Elbe and Elbe estuary (Hamburg, Germany) until the German Bight. This dataset is about the cruise "Sternfahrt 5" from August 31 to September 03 in 2020, with the objective to detect the spatial extension of the riverine influence of Elbe and Weser. Therefore, three research vessels have been involved to cover a broad area of the German Bight between Hamburg, Heligoland and Sylt. All three research vessels (Littorina, Ludwig Prandtl and Mya II) started together on the first day from Cuxhaven to Heligoland. The first day and whenever two or three of the ships met, one measuring was made together as inter-calibration station (for more details, see file description), in total four. From the second day the ship Littorina travelled between Heligoland and Büsum, one track each day. The Ludwig Prandtl headed the second day towards Wyk auf Föhr. Afterwards the crew navigated further north towards Sylt and turning back to Wyk on the same day. The last day they went back from there to Cuxhaven meeting with the vessel Littorina for a last inter-calibration station. The vessel Mya II instead was navigating on the second and third day first to Bremerhaven and on a more western track back to Heligoland. To also cover the northern part of the research area, on the last day the crew travelled to Sylt, the home harbour of the vessel. Therefore, it was not participating on the last inter-calibration station off Cuxhaven. All ships took measurements of basic hydrographic parameters (salinity, temperature, oxygen saturation, pH) and atmospheric and dissolved greenhouse gases (methane and carbon dioxide). The parameters were measured continuously on the way by specific sensors submerged in a water reservoir on deck which was supplied with surface water (about 1m depth) from the underway water supply of the vessel. Methane and carbon dioxide were measured in the surface water and in the atmosphere with the sensors "LosGatos" and "Picarro". Ferrybox systems measured physical and chemical oceanographic parameters including salinity, temperature, pH. At specific stations along the tracks additionally vertical profiles were taken as well as water samples from the surface. The respective data can be found in: Bussmann, Ingeborg, Flöser, Götz, Geißler, Felix (2021): Carbon compounds, nutrients and pigments from water samples from MOSES project's cruise Sternfahrt 5. PANGAEA, https://doi.org/10.1594/PANGAEA.934894. Further profile data can be found in the AWI O2A-Database as download. Additional information about the whole campaign and different cruises can be found in the article(s) cited.

The data were taken in situ on board of three research vessels continuously measuring surface water. Afterwards the datasets were reviewed and a standardized plausibility control was conducted (Argo-Standards, R-Script written by Philipp Fischer for spike, gradient, range check) with all parameters except for wind direction. To align the data between the ships the following procedure was applied. At four inter-calibration intervals the three vessels were within close distance (100 – 600 m), continuously sampling the same water body. Next the data (for example temperature) were compared between the ships, over the complete time of the cruise and over the inter-calibration intervals. From these comparisons a correction factor was calculated and applied to all data. For example, on Stern-5 the water temperature from Littorina was used as lead sensor, and to the data from Prandtl +0.03° were added, and -0.07° were subtracted from the data from the Mya. For more details see "Device descriptions from ship measurement systems".