During RV Polarstern expedition PS131 to the Arctic Ocean, a number of hydrographic profiles were obtained using a ship-based Seabird SBE911plus CTD rosette system. The expedition, also referred to as "ATWAICE": ATlantic WAter pathways to the ICE, took place between 28 June and 17 August 2022 and investigated sea ice and ocean properties in the Arctic Ocean, with a focus on sea ice melt processes. The main work areas included Fram Strait, the marginal ice zone northwest of Svalbard, and the East Greenland coast close to the 79°N glacier. A few stations were also done at the Aurora vent field and in Scoresby Sound, Greenland. This dataset comprises the processed data of all 64 CTD stations performed during this expedition, bin-averaged to 1dbar values. The AWI standard software ManageCTD was used for pre-processing, also incorporating selected standard SeaBird processing routines. Station metadata was aligned to the ship's action log. Outliers were identified and interpolated. The list of parameters includes measurement pressure/depth, seawater temperature, conductivity, salinity, dissolved oxygen, optical beam transmission, Chl-a and CDOM fluorescence, photosynthetically active radiation (PAR), along with selected derived variables. Temperature, conductivity/salinity and oxygen were chosen from two independent sensors sets. Temperature offset was corrected using post-cruise calibration results. Salinity was calibrated against in-situ samples measured by an Optimare Precision Salinometer. Dissolved oxygen was calibrated against in-situ samples analyzed by means of Winkler titration. Temporal and pressure drift of these parameters were identified, and corrected accordingly. The optical measurements were converted according to the manufacturer calibration of the respective instrument, but not calibrated against any other measurements. An overview of the sensor configuration and a detailed description of all individual steps is available in the attached processing report, which also includes all relevant calibration sheets.

Acknowledgments: We are grateful to the PS131 crew and scientists onboard RV Polarstern for their help in obtaining the data during this expedition.