This dataset contains the raw electromagnetic induction (EM) measurements from repeated walks with the GEM instruments on a sledge across ice floes (called long transects) conducted during the PS149 CONTRASTS expedition. All measurements were acquired using the Geophex Ltd. GEM-2-730 broadband EM sensor. During each ice station (i.e., floe visit), a long transect was traversed across the ice floe to obtain statistically representative distributions of snow/pond depth and ice thickness. Each transect was marked with flags at its corner points to ensure that a similar track was measured during repeated visits to each ice floe. This dataset provides only the raw GEM measurements acquired along these transects, including in-phase and quadrature responses, as well as electrical conductivity and magnetic susceptibility of sea ice and snow / melt ponds. These raw data enable users to apply various processing methods to, e.g., derive sea ice thickness. For reference, processed sea ice thickness derived from these measurements (using the gem2-seaice-toolbox, https://gitlab.awi.de/sitem/gem2-seaice-toolbox), along with co-located MagnaProbe snow and pond depth measurements, are available in the Level 2 dataset (doi:10.1594/PANGAEA.996908).
Raw data acquired by two SBE21 thermosalinograph and two auxiliary SBE38 temperature sensor (Sea-Bird Scientific, USA) installed in an underway seawater flow-through system on board RV Polarstern were processed to yield a calibrated and validated data set of temperature and salinity along the cruise track. Data were downloaded from DAVIS SHIP data base (https://dship.awi.de) at a resolution of 1 sec, and converted to temperature and conductivity using the pre-deployment factory calibration coefficients. The converted data were averaged to 1 min values, outliers were removed, and sensor drift was corrected using coefficients obtained from a post-season calibration performed at Sea-Bird at the end of the measurement season. Salinity was calculated from internal temperature, conductivity and pressure according to the PSS-78 Practical Salinity Scale. Processed data are provided as 1 min means of seawater temperature, conductivity and salinity, aligned with position data taken from the master track. Quality flags are appended according to the SeaDataNet Data Quality Control Procedures (version from May 2010). More details are described in the attached processing report.
Raw data acquired by two SBE21 thermosalinograph and two auxiliary SBE38 temperature sensor (Sea-Bird Scientific, USA) installed in an underway seawater flow-through system on board RV Polarstern were processed to yield a calibrated and validated data set of temperature and salinity along the cruise track. Data were downloaded from DAVIS SHIP data base (https://dship.awi.de) at a resolution of 1 sec, and converted to temperature and conductivity using the pre-deployment factory calibration coefficients. The converted data were averaged to 1 min values, outliers were removed, and sensor drift was corrected using coefficients obtained from a post-season calibration performed at Sea-Bird at the end of the measurement season. Salinity was calculated from internal temperature, conductivity and pressure according to the PSS-78 Practical Salinity Scale. Processed data are provided as 1 min means of seawater temperature, conductivity and salinity, aligned with position data taken from the master track. Quality flags are appended according to the SeaDataNet Data Quality Control Procedures (version from May 2010). More details are described in the attached processing report.