Estimation of First-Year Sea Ice Thickness With Seafloor Distributed Acoustic Sensing Using Flexural-Gravity Waves From Environmental and Anthropogenic Sources.
Description:
Monitoring programs for sea ice thickness currently rely on estimations of freeboard height collected by satellite-based instrumentation. These methods, however, provide only kilometer-scale resolution and may suffer data blackouts in regions with excessive surface ponding or where high density ice pack prevents measurements of local sea level. Here, we show that distributed acoustic sensing (DAS) on a trenched seafloor telecommunications cable in shallow (<10 m) coastal waters at Oliktok Point, Alaska, can be used to provide estimates of sea ice thickness by inverting for flexural-gravity (FG) wave dispersion curves. We use data from multiple one-week campaigns during the winters of 2021 and 2022, the first such DAS data ever recorded beneath ice-capped waters. We leverage a variety of FG wave sources, including environmentally-driven icequakes, a commuter hovercraft, and ice road traffic. These sources generate short-to-mid period (0.5–20 s) FG wave trains that propagate coherently for several kilometers and are observed by the seafloor DAS via hydrostatic pressure transients. Dispersion curves may be extracted with established array processing techniques, with an assumption of near-field radiation patterns. Using a simple grid search across candidate snow, ice, and water thicknesses, we then estimate ice thickness by minimizing the misfit between observed and predicted FG wave dispersion curves. This method has potential for site-specific monitoring of sea ice at spatial and temporal resolutions greatly exceeding those of satellite-based methods.
SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.
Session: Monitoring Climate Change With Seismology [Poster]
Type: Poster
Date: 4/18/2023
Presentation Time: 08:00 AM (local time)
Presenting Author: Michael G. Baker
Student Presenter: No
Invited Presentation:
Authors
Michael Baker Presenting Author Corresponding Author mgbaker@sandia.gov Sandia National Laboratories |
Robert Abbott reabbot@sandia.gov Sandia National Laboratories |
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Estimation of First-Year Sea Ice Thickness With Seafloor Distributed Acoustic Sensing Using Flexural-Gravity Waves From Environmental and Anthropogenic Sources.
Category
Monitoring Climate Change With Seismology