The aim of the survey was to record the vertical profiles of the currents and the salinity, temperature, and oxygen concentration in the demersal zone in the area of the wreck of the ferry Estonia in conditions where the water column is stratified. The work was carried out using the SeaGuard II measurement platform from Aanderaa, which was connected to an acoustic Doppler current profiler and pressure, electrical conductivity, temperature, and oxygen sensors. The platform, connected to a submersible buoy and anchored to the seafloor, was deployed from the Transport Administration’s vessel EVA-316 in the vicinity of the wreck of the Estonia on 10 July 2021 at 59° 22.8299' N, 21° 38.8656' E. The depth of the seafloor at the measurement site was 74 m. The platform was retrieved by the Police and Border Guard Board’s vessel Kindral Kurvits on 9 November 2021. The series of data collected over the nearly four months are presented in the annex to this report. The report describes the temporal variability of the currents across the whole water column, focusing in particular on the dynamics of the demersal zone. Periods of higher current velocity in the deep layer are identified, and, based on meteorological data for the measurement period, the conditions that prevailed during strong currents are described. The temporal variability of the salinity and dissolved oxygen concentration in the demersal zone in the area of the wreck of the Estonia during July to November 2021 and December 2021 to March 2022 is analysed.
The work has been carried out in accordance with the order of the Estonian Safety Investigation Bureau from 6 July 2021 and the procurement contract (public procurement reference number 241513) from 13 October 2021.
The measurements, data analysis, and preparation of the report were carried out with the involvement of experts Villu Kikas, Oliver Samlas, Kai Salm, Stella-Theresa Stoicescu, and Urmas Lips from the Department of Marine Systems of Tallinn University of Technology.
Reports can be read in the attached pdf documents:
