Current, temperature, conductivity, and pressure time series from moorings deployed in Orkney Passage (2019-2023)

Six sub-surface oceanographic moorings were deployed in Orkney Passage from RRS James Clark Ross cruise JR18004 in 2019, as part of the ORCHESTRA (Ocean Regulation of Climate through Heat and Carbon Sequestration and Transports) project. The intention was to recover these in 2021, but because of the COVID pandemic and delays to the completion of RRS Sir David Attenborough this was not scheduled until 2023, on RRS Discovery cruise DY158. Funding for the recovery was partly through ENCORE, mainly through BIOPOLE (Biogeochemical processes and ecosystem functioning in changing polar systems and their global impacts). The deployment extends the BAS time series of mooring observations in Orkney Passage going back to 2007. The moorings are intended to cover the outflow of Weddell Sea Deep Water through the passage into the Scotia Sea, measuring the variability and long-term changes in transport and water mass properties. Data processing and quality control have been completed by Povl Abrahamsen using the same methods as for prior mooring deployments. Because of the longer-than-anticipated deployment, the current meters ran out of battery after approx. 3 years, while several other instruments continued for the full duration of the deployment. So most of the transport time series end after three years, while some of the temperature and/or conductivity time series continue up to four years.