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Session: Exploring the Frontier of Environmental Processes using Fiber-optic Sensing [Poster]

Type: Poster

Date: 10/9/2024

Time: 07:00 AM

Room: Stanley Park Ballroom

Correlation of DAS Strain Data and Oceanographic Variables in the North-East Atlantic

DAS recordings close to the coast are influenced by pressure signals from land- and seaward ocean surface gravity waves. The amplitude and period of the signal can be interpreted as a proxy for the sea state. Measurements along the cable at larger water depths show secondary microseisms related to the sea state away from the shore. The significant wave height (SWH) and ocean currents along the cable can be evaluated continuously during the experiment, resembling a dense sampling array of closely spaced buoys. However, in order to provide serviceable results, the measurements have to be calibrated with existing buoy or wave model data.

In October 2023, the GeoLab dark fibre off Madeira Island in the Atlantic was fitted with a DAS interrogator under a project by ARDITI and the Oceanic Observatory of Madeira. As a pilot site, the experiment is linked to the SUBMERSE project that is trying to establish continuous DAS monitoring along fibre-optic cables at multiple locations around Europe.

We use a one-week recording in late 2023 to show changes in the DAS data close to the shore where the water depth is small, and temporal variations of the secondary microseisms further along the cable. Spectrograms of individual channels and f-k spectra of different time intervals show effects of varying sea states, such as currents on the dispersion curves between land- and seaward waves.

To calibrate the measurements, the data are compared with measurements from a buoy located close to the coast and the DAS cable. In addition, we use model data from the Atlantic-Iberian Biscay Irish-Ocean Wave Analysis and Forecast model (0.05 x 0.05 deg; Toledano et al., 2022), which shows good correlation with the buoy data.

This work was funded by the Portuguese Fundação para a Ciência e a Tecnologia (FCT) I.P./MCTES through national funds (PIDDAC) – UIDB/50019/2020 (DOI: 10.54499/UIDB/50019/2020), UIDP/50019/2020 (DOI: 10.54499/UIDP/50019/2020) and LA/P/0068/2020 (DOI: 10.54499/LA/P/0068/2020), and by EC project SUBMERSE, HORIZON-INFRA-2022-TECH-01-101095055.

Presenting Author: David

Additional Authors