An integrated high resolution tide and storm surge model has been developedfor all of coastal Alaska. The model uses the ADCIRC basin-to-channelscale unstructured grid circulation code. Tidal forcing from global tidal modelsand meteorological forcing from the Climate Forecast System Reanalysisare used. The model’s tidal solution has been validated at 121 shelf andnearshore stations. The model’s skill has been investigated for summer, falland winter storms. Sea ice has been incorporated through a parameterizedwind drag coefficient which modifies the air-sea drag under ice coverage.Three large storms with distinctly different ice coverages were chosen to exhibitthe effect of sea ice on the resulting storm surge. The root mean squareerror does not exceed 20 cm at any station. Forming coastal ice coverageincreases coastal water levels, but the peaks are under predicted at the validationstations. Under dense pack ice, an increase in momentum transfer inthe marginal sea ice at the shelf break leads to increased coastal water levelsdespite the decreased wind stress across the shelf pack ice. In highly variableice fields, results are mixed, as the underlying assumptions about ice movementused to derive the drag parameterization may fail. To improve modelperformance for coastal water levels, it would be desirable to include the contributionof wave radiation stresses induced in marginal ice zones. Furthermore,including sea ice drift and current speeds explicitly in the air-sea-icedrag formulation would improve the description of momentum transferred tothe water column.
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“Modeling Tides & Storm Surge Under Varying Sea Ice Conditions in the Gulf of AK”
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