Rapid Refreezing of a Marginal Ice Zone Across a Seafloor Distributed Acoustic Sensor

• Published in: Geophysical research letters Vol. 49; no. 24
• Main Authors: Baker, Michael G., Abbott, Robert E.
• Format: Journal Article
• Language: English
• Published: Washington John Wiley & Sons, Inc 28.12.2022; American Geophysical Union (AGU)
• Subjects: Acoustic imagery; Acoustics; Ambient noise; Anthropogenic factors; Beaufort Sea; Broadband; Cables; Cloud cover; Communication cables; Cryoseismology; distributed acoustic sensing; Fiber optics; Geophysical observatories; Ice cover; Ice formation; Instrumentation; Instruments; Marine mammals; Monitoring instruments; New technology; Ocean floor; Ocean waves; Oceans; Optical fibres; Resolution; Sea ice; Sea ice formation; Seismographs; Seismometers; Sensors; Spatial discrimination; Spatial resolution; Surface craft; Surface water waves; Technology; Telecommunications
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2022GL099880

Seismic instruments such as broadband seismometers and distributed acoustic sensors (DAS) have a demonstrated potential for wide‐scale and continuous in situ monitoring of near‐surface environmental and anthropogenic processes. DAS is attractive for development as a multi‐geophysical observatory due to the prevalence of existing fiber infrastructure in regions with environmental, cultural, or strategic significance. Here we present results from a multi‐seasonal acquisition of DAS data on a seafloor cable in the Beaufort Sea, Alaska. During a November 2021 data collect we captured the rapid transition of ambient noise characteristics from an “ice‐free” state to an “ice‐bound” state. A sea ice formation front was plainly visible on the DAS record and was observed to propagate 20 km seaward over a period of 8 hr. Satellite‐based instrumentation were unable to record this event due to cloud cover, low light conditions, and orbital frequency. Plain Language Summary Distributed acoustic sensing (DAS) is an emerging technology that uses fiber optic cable to mimic a high resolution array of one dimensional seismometers. Distributed acoustic sensors is compatible with any single‐mode fiber optic cable, including seafloor telecommunications cables. Previous recordings of DAS data on seafloor cables have demonstrated that this technology is able to detect and track individual ocean waves, surface vessels, and whales. In this first‐ever acquisition of DAS data from a seafloor beneath a frozen ocean, we show that DAS is also capable of mapping sea ice coverage with unprecedented spatial resolution and can track sea ice formation and breakup up in near real time. Key Points Seafloor distributed acoustic sensing can distinguish between sea ice and open water on the basis of endemic wave modes This technology is capable of high resolution, near real time imaging of sea ice dynamics, such as rapid freezing of marginal ice This can complement large scale, low resolution satellite‐based imaging in regions of high scientific or operational importance