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Wave-Ice Interaction for Regional Applications: SWAN Developments and Validations
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  • Nirnimesh Kumar,
  • W. Erick Rogers,
  • Jim Thomson,
  • Clarence Collins
Nirnimesh Kumar
University of Washington
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W. Erick Rogers
Naval Research Laboratory

Corresponding Author:[email protected]

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Jim Thomson
University of Washington
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Clarence Collins
USACE - ERDC - CHL - FRF
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Abstract

Interaction between surface gravity waves and sea-ice in the marginal ice zone is complex, and most of the prior research focus has been in deeper oceans. Here, the regional wave model Simulating WAves Nearshore (SWAN) is configured to simulate reduced wind-generation and wave dissipation in the presence of sea-ice. The wind-generation process is modified by scaling the generation terms with the open-water fraction, while wave dissipation in the presence of sea-ice is simulated as an exponential energy decay as function of ice concentration, wave frequency and empirical coefficients determined from prior experiments. Modified SWAN is used to simulate interaction between regional sea-ice and a swell event in the Barents Sea. The simulation accounting for wave-ice interaction reasonably agrees with field measured significant wave height and the energy spectral density. Additional simulations are conducted for the shallow seas of Gulf of Bothnia, located in the northernmost reach of the Baltic sea. Modeled wave dynamics in this region agrees well with satellite altimetry based measurements. This model setup is further investigated to understand fetch scaling in the marginal ice zone, and non-dimensional energy scales well with a non-dimensional fetch determined from a cumulative fetch dependent on ice concentration. Additional implications for Stokes drift and Stokes drift shear are also discussed for the Bothnian bay. Finally recommendations for including dissipation due to ice thickness, and plans for future model coupling are considered.