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Wind-wave Scaling in Antarctic Coastal Polynyas From Microseism Observations

Description: 

Antarctic latent-heat polynyas, partially open areas of water along the coast, are sustained by a wind-driven equilibrium between sea-ice production and export. The same katabatic wind events that sustain polynyas also excite ocean surface gravity waves, which may influence polynya processes by applying a radiation stress at the ice edge, mediating air-sea transfers through breaking, and shaping the ice formation process through wave-induced rafting and collisions. Yet, the scaling of wind-wave growth in partially ice-covered water and, in particular, the wind-wave climatology of Antarctic polynyas remains unobserved, due to the difficulty of conventional buoy measurements in sea ice. Here, we report that episodic bursts of short-period secondary microseism observed at seismic stations in coastal regions of Antarctica can serve as a quantitative proxy for ocean surface gravity wave statistics in nearby polynyas. Interdisciplinary data sets, including seismic noise, remote sensing of sea ice concentration, and ERA5 atmospheric reanalysis, are integrated to constrain the physical process of wind-wave development in the Amundsen Polynya in the Amundsen Sea, West Antarctica. We find that the seismic energy and peak frequency scale with an effective fetch (the distance wind blows over), which is a function of polynya size, sea-ice concentration, and wind speed. Peak frequency scales with effective fetch, defined by a sea-ice concentration threshold of 0.6, following power-law model with an exponent of -0.3, close to the classic fetch-limited scaling law from open ocean, buoy observations (e.g. JONSWAP). The seismic energy and fetch are also highly correlated, following a power law with an exponent of 1.7, about 2 times higher than the classic fetch-limited scaling. This may indicate a positive correlation between directional spreading of ocean waves and fetch, highlighting the scattering effects of ocean waves due to ice floes. Our results demonstrate that seismic observation is an effective way to monitor sea state in polar regions and shed light on the physics of wind-wave development in partially ice-covered seas.

Session: Cryoseismology: Advances in Technology and Scientific Discovery [Poster]

Type: Poster

Date: 4/15/2026

Presentation Time: 08:00 AM (local time)

Presenting Author: Minghan Yang

Student Presenter: Yes

Invited Presentation: 

Poster Number: 3

Authors