A modified Pacific Gyre SVP Drifter with a 400 m long tether and a bottom weight was deployed during Polarstern expedition PS118 (9 February - 10 April 2019) on the western Weddell Sea shelf. The drifter was deployed from ~2m-thick sea ice through an ice hole following a CTD profile. The inductive tether was equipped with two SBE37IM (CTD) and one SBE39IMplus (T). The surface buoy included a sensor to measure sea level pressure and temperature right above the sea ice. The surface unit sampled the sensors each 15-30 minutes, and subsequently transmitted the data via iridium to the Pacific Gyre data server.The drifter was deployed on 8 March 2019 and terminated the communication on May 2019.

Note 1: The ice-based surface unit drifted across regions with variable water depth, often shallower than the 400m long tether, so that the bottom weight and lower sensors were pulled along the seafloor, which was characterized by muddy/sandy sediments. This likely resulted in a plugged conductivity cell (hence bad salinity data) of the lower SEB37, which is flagged by the 37IMSalinity2-flag.Note 2: Ocean currents and/or ice drift resulted in lifting of the tether and instruments, which resulted in strongly variable sampling depths, in particular of the two lower instruments, as can be inferred from the pressure records.For more information, contact markus.janout@awi.de