Sea ice draft, under-ice irradiance and radiance, and surface water temperature, salinity and chlorophyl a from Surface and Under Ice Trawl (SUIT) measurements in 2012-2017

Surface and Under Ice Trawl (SUIT) deployments have been carried out during five expeditions (PS80, PS81, PS89, PS92, PS106) on board of the RV Polarstern in both the Arctic and Antarctic between 2012 and 2017. The SUIT is equipped with a CTD probe (Sea and Sun Technology CTD75M memory probe) to measure surface water temperature and salinity at a sampling interval of 0.1s, later interpolated to a 0.5m grid. A fluorometer integrated in the CTD allows surface chl a measurements and an altimeter allows to measure the distance of the SUIT from the ice underside. An Acoustic Doppler Current Profiler (ADCP; Nortek Aquadopp Profiler) with three acoustic beams is used to measure water inflow speed and direction, pitch and roll angles, and pressure. Information on pressure, distance from the ice above, and pitch and roll have been combined to obtain sea-ice draft on a 0.5m grid. Hyperspectral measurements have been performed with Ramses spectral radiometers (Trios, Rastede, Germany), then integrated over the PAR range. Positions are obtained from the ship GPS and used to retrieve speed and length of trawling.