Shipborne Dissolved Organic Gas Measurements in Depth Profiles and Underway Seawater (Methanol, Acetone, Acetaldehyde, DMS, Isoprene) Amundsen 2017

Dissolved concentrations of these gases were measured using a segmented flow coil equilibrator (SFCE) coupled to a Proton Transfer Reaction Mass Spectrometer (PTR-MS). For more information, please refer to Wohl, C., Capelle, D., Jones, A., Sturges, W. T., Nightingale, P. D., Else, B. G. T., and Yang, M.: Segmented flow coil equilibrator coupled to a proton-transfer-reaction mass spectrometer for measurements of a broad range of volatile organic compounds in seawater, Ocean Sci., 15, 925–940, https://doi.org/10.5194/os-15-925-2019, 2019. Detailed description of the installation on board and the data analysis specific to this deployment can be found in the data citation. Briefly, the SFCE-PTR-MS was set up in one of the labs near the front of the ship and used to sample either discrete samples from depth profiles or underway seawater from the main seawater inlet of the ship. The research vessel travelled from Iqaluit northwards through Davis Strait and Baffin Bay to reach Smith Sound. In this area, more intense depth profile sampling was carried out. The vessel then travelled to Pond Inlet and Resolute. Sampling ended south of Resolute in Peel Sound. Depth profiles of dissolved gas concentrations were measured from the Rosette-mounted Niskin bottles as discrete samples from the near surface (about 2 m) to 60 m depth at a total of 21 stations as per availability. The exact sampling depth as determined by the CTD crew is listed in the "CTD concentrations" data file. When logistically feasible at station, a handheld vertical 5 dm^(3) Niskin bottle was deployed off the front starboard side of the ship to sample approximately the top 30 cm from the ocean surface. This was done by bringing the Niskin bottle up from approximately 3 m and firing it just before it reached the surface using rope marks as depth indicators, similar to described in Ahmed et al. (2020). Samples collected with this method are marked as sampled from 0.3 m in the "CTD concentrations" data file. The AMSR2 passive microwave sea ice concentration (SIC) satellite product (daily, 3.125 km x 3,125 km resolution) (Spreen et al., 2008) was used to create a time series of sea ice concentration along the cruise track.