Previous Sternfahrten were mainly conducted in spring and summer. To cover the seasonal aspects more thoroughly, including a winter situation, this cruise was conducted in late autumn (20 -22 November 2025 ). We used the RV Heincke (cruise HE673/2) instead of the RV Uthörn. The Heincke's draught is greater, so we could not reach all of our previous stations. Surface and bottom water samples were taken with a rosette.
Raw data acquired by a thermosalinograph (SBE21, Sea-Bird GmbH) in combination with an external temperature sensor (SBE38, Sea-Bird GmbH) aboard RV Heincke were processed to generate a calibrated, quality-controlled dataset of seawater temperature and salinity. The raw sensor data were initially retrieved from the DSHIP database (https://dship.awi.de) at a temporal resolution of 1 second and converted into temperature and conductivity using the pre-deployment calibration coefficients. The thermosalinograph system aboard RV Heincke is typically replaced after each expedition season, with a recalibration conducted at the manufacturer's facilities after each exchange. After post-cruise recalibration of the instruments, additional correction factors were calculated and applied to account for sensor drift. Salinity was calculated from internally measured temperatures and conductivities following the Practical Salinity Scale (PSS-78). The processed dataset is provided as 1-minute averages of salinity and seawater external temperature, synchronized with the positional data from the expedition's master track. Quality flags were assigned in accordance with the SeaDataNet Data Quality Control Procedures (May 2010).
Raw data acquired by a thermosalinograph (SBE21, Sea-Bird GmbH) in combination with an external temperature sensor (SBE38, Sea-Bird GmbH) aboard RV Heincke were processed to generate a calibrated, quality-controlled dataset of seawater temperature and salinity. The raw sensor data were initially retrieved from the DSHIP database (https://dship.awi.de) at a temporal resolution of 1 second and converted into temperature and conductivity using the pre-deployment calibration coefficients. The thermosalinograph system aboard RV Heincke is typically replaced after each expedition season, with a recalibration conducted at the manufacturer's facilities after each exchange. After post-cruise recalibration of the instruments, additional correction factors were calculated and applied to account for sensor drift. Salinity was calculated from internally measured temperatures and conductivities following the Practical Salinity Scale (PSS-78). The processed dataset is provided as 1-minute averages of salinity and seawater external temperature, synchronized with the positional data from the expedition's master track. Quality flags were assigned in accordance with the SeaDataNet Data Quality Control Procedures (May 2010).
In continuation of the previous cruises (Sternfahrten) we covered a similar area with the RV Heincke but in late autumn (20 - 22 November 2026). All instruments were set up in the MOSES laboratory container. Standard hydrographic parameters were determined with a pocket ferrybox running with ship's surface water supply. In addition, dissolved methane was determined continuously. We used a degassing unit which was using surface water from the ship's water supply. The gas mixture was subsequently analysed with a Greenhouse Gas Analyzer from LosGatos. Conversion to methane concentration was performed with water samples, from which the methane content was determined with gas chromatography. Atmospheric methane concentrations were obtained from the ICOS-station Helgoland. Wind speed was obtained from the ships meteorological systems. The diffusive flux was calculated as outlined in the additional meta data description.