The two platforms IAOOS 23 and IAOOS 24 were deployed within 600 m from each other at the North Pole from the Russia-operated Barneo ice camp on April 12, 2017. They followed a meandering trajectory, reaching as far as 30°E in the Nansen Basin, before turning back to the western Fram Strait. On both IAOOS 23 and 24, the ocean profiler was a PROVOR SPI (from French manufacturer NKE) equipped with a Seabird SBE41 CTD (Conductivity, Temperature, Depth) and a dissolved oxygen (DO) Aandera 4330 optode. For the first time, the profiler on IAOOS 23 also carried biogeochemical sensors. It featured a bio-optics sensor suite and a submersible ultraviolet nitrate analyzer (SUNA, Satlantic-Seabird Inc.). The bio-optics sensor suite (called Pack Rem A) combines a three-optical-sensor instrument (ECO Triplet, WET Labs Inc.) and a multispectral radiometer (OCR-504, Satlantic Inc.). The present dataset is composed of CTD-DO data from IAOOS 23 and 24, corrected from the thermal lag and the sensor lag, despiked and interpolated vertically every 0.5 m. It also comprises nitrate concentrations from the SUNA and CDOM fluorescence from the WETLabs ECO sensor on IAOOS 23. Other biogeochemical data will be added to this dataset. The profilers were set to perform two upward profiles a day from 250 m (IAOOS 23) and 350 m (IAOOS 24) upward starting at approximately 6 am and 6 pm. They provided a unique 8-month long dataset, gathering a total of 793 profiles of the temperature, salinity and oxygen (upper 350m) and 427 profiles of CDOM and nitrates concentrations (upper 250m).  

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