Turbulent Mixing in the Slupsk Furrow (Southern Baltic): Microstructure observations in 2019-2022.

Abstract

The Slupsk Furrow, located on the main pathway of the inflow waters from the North Sea, is of key importance for the Baltic circulation and ecosystem. The dynamics of the Slupsk Furrow make it one of the principal areas of intensive mixing and transformation of deep waters on their way futher east. Internal waves and mesoscale eddies are dominant features of the water transport through the channel. We present a summary of the measurements collected in the Slupsk Furrow in 2019-2022 focusing on the microstructure measurements collected every 5-10 nm during three cruises of rv Oceania through the central channel and at two stations located on the southern topographic slope. Microstructure observations were collected using a free falling Vertical Microstructure Profiler (VMP) 250 of Rockland Scientific equipped with two shear, one micro-conductivity, one micro-temperature and a standard CTD (64 Hz) sensors. In total, 170 microstructure profiles (34hr) were collected in November 2020, 109 profiles (18 hr) in May 2021 at the station to the east of the Slupsk Sill and 354 profiles were collected in December 2021 (14 hr) and March 2012 (156 hr) at the southern topographic slope of the channel. The spatial and temporal variability of mixing intensity is presented and discussed. This research was financed by the National Science Centre (NCN) Poland, grant no. 2019/33/B/ST10/02189: “Turbulent mixing in the Slupsk Furrow (Southern Baltic)” project.