The effect of pseudofrazil particle entrainment on salinity measurements: Data

This experiment was designed to investigate the effect of entraining frazil ice particles found in supercooled ocean water by mimicking their effect through plastic particles of similar material properties as ice. This was done in order to better control the volume concentration of the particles and avoid damage to sensors by icing which is common in supercooled water. In total six experiments were run in which non-spherical round polyamide-12 seeding particles made by Dantec Dynamics A/S with a mean diameter of 50 micro meters were added to natural saltwater tinged with surfactant whilst recording temperature and conductivity with Sea-Bird Electronics sensors. Surfactant was Ecostore-brand eucalyptus laundry liquid (ingredients can be found here: https://ecostore.com/au/eucalyptus-laundry-liquid-409/, last accessed July 2022). Experiments are H1, H2 and HC performed with saltwater taken from Otago Harbour, Dunedin, New Zealand and M1, M2 and MC performed with saltwater taken from the Munida Transect offshore of Otago Peninsula, Dunedin, New Zealand. HC and MC were run in a walk-in freezer with water temperatures around -1 degrees C, all other experiments were performed at ambient room temperatures. The setup consisted of a 30 litre bucket containing 24 litres of seawater filtered to 1 micro meter. Surfactant was added to the water to aid particle dispersion. Subsequently particles were added in increments to a total mass of particles in the bucket of 100 g. Temperature was recorded with a SBE3plus temperature sensor and conductivity with a SBE4C sensor. These were connected to a SBE pump with standard SBE CT ducting. Data were recorded with a SBE31 deck unit connected to a laptop computer. Data were recorded continuously, times at which particles were added or other operations performed are given in the tables <experimentname>info.xlsx Raw data were converted using the sensors' calibration coefficients and corrected for CT offset and cell thermal mass using the SBE data processing software and standard values for sensors configured as in the SBE911+ setup, which is equivalent to the ducting used by us. A manuscript with results from these experiments is available as Richter, M. E., et al., 2023, The Effect of Pseudofrazil Particle Entrainment on Salinity Measurements, Earth and Space Science, doi:10.1029/2022EA002564 .