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Abstract Declining Arctic sea ice over recent decades has been linked to growth in coastal hazards affecting the Alaskan Arctic. In this study, climate model projections of sea ice are utilized in the simulation of an extratropical cyclone to quantify how future changes in seasonal ice coverage could affect coastal waves caused by this extreme event. All future scenarios and decades show an increase in coastal wave heights, demonstrating how an extended season of open water in the Chukchi and Beaufort Seas could expose Alaskan Arctic shorelines to wave hazards resulting from such a storm event for an additional winter month by 2050 and up to three additional months by 2070 depending on climate pathway. Additionally, for the Beaufort coastal region, future scenarios agree that a coastal wave saturation limit is reached during the sea ice minimum, where historically sea ice would provide a degree of protection throughout the year.
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The Critical Role of Sea Ice Products for Accurate Wind‐Wave Simulations in the Arctic
Abstract The Arctic region is experiencing significant changes due to climate change, and the resulting decline in sea ice concentration and extent is already impacting ocean dynamics and exacerbating coastal hazards in the region. In this context, numerical models play a crucial role in simulating the interactions between the ocean, land, sea ice, and atmosphere, thus supporting scientific studies in the region. This research aims to evaluate how different sea ice products with spatial resolutions varying from 2 to 25 km influence a phase averaged spectral wave model results in the Alaskan Arctic under storm conditions. Four events throughout the Fall to Winter seasons in 2019 were utilized to assess the accuracy of wave simulations generated under the dynamic sea ice conditions found in the Arctic. The selected sea ice products used to parameterize the numerical wave model include the National Snow and Ice Data Center (NSIDC) sea ice concentration, the European Centre for Medium‐Range Weather Forecasts (ECMWF) Re‐Analysis (ERA5), the HYbrid Coordinate Ocean Model‐Community Ice CodE (HYCOM‐CICE) system assimilated with Navy Coupled Ocean Data Assimilation (NCODA), and the High‐resolution Ice‐Ocean Modeling and Assimilation System (HIOMAS). The Simulating WAves Nearshore (SWAN) model's accuracy in simulating waves using these sea ice products was evaluated against Sea State Daily Multisensor L3 satellite observations. Results show wave simulations using ERA5 consistently exhibited high correlation with observations, maintaining an accuracy above 0.83 to the observations across all events. Conversely, HIOMAS demonstrated the weakest performance, particularly during the Winter, with the lowest correlation of 0.40 to the observations. Remarkably, ERA5 surpassed all other products by up to 30% in accuracy during the selected storm events, and even when an ensemble was assessed by combining the selected sea ice products, ERA5's individual performance remained unmatched. Our study provides insights for selecting sea ice products under different sea ice conditions for accurately simulating waves and coastal hazards in high latitudes.
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- Award ID(s):
- 1927785
- PAR ID:
- 10635319
- Publisher / Repository:
- AGU
- Date Published:
- Journal Name:
- Earth and Space Science
- Volume:
- 12
- Issue:
- 2
- ISSN:
- 2333-5084
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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### Access All files can be accessed and downloaded from the directory via: [http://arcticdata.io/data/10.18739/A2MW28G9D](http://arcticdata.io/data/10.18739/A2MW28G9D). ### Overview Storm surge extremes are intensifying across Arctic coastlines, yet limited observational records hamper detailed spatial and temporal characterization of these events. To address that, this data is a 45-year hydrodynamic hindcast of storm-driven water levels across Northern and Western Alaska. We utilize ADCIRC+SWAN to simulate interactions between the ocean, land, sea ice, and atmosphere, focusing on the period from 1979 to 2024 for Western to Northern Alaska coasts. Data from the European Centre for Medium-Range Weather Forecasts Re-Analysis (ERA5), including sea ice concentration and atmospheric forcing were utilized to support these simulations, which investigate annual conditions in the Alaskan Arctic. The Processed_DATA dataset contains extracted parameters for communities located in western to northern Alaska. For other areas in the state not included here, please refer to the Raw_DATA file. ### Goal The goal of this study's data is to attribute long-term changes in Arctic storm surge extremes to evolving physical drivers—primarily the transition from sea-ice-dominated to wind-driven surge regimes. Furthermore, to fill in the gap in observed water levels and wave conditions throughout Alaska. ### Methods This study’s hindcast model framework is to evaluate the storm driven water levels from 1979 to 2024. The framework integrates a coupled hydrodynamic–wave model driven by time-varying boundary inputs representing atmospheric, oceanic, tidal, and sea ice conditions. We used the coupled Advanced CIRCulation and Simulating WAves Nearshore model (ADCIRC+SWAN) to simulate water levels and wave conditions.more » « less
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Ping Wang, Elizabeth Royer (Ed.)Arctic storm surge events have a distinct character, and their impact on the coast is unique compared to a non-Arctic event. On the one hand, Arctic peak wind speeds rarely reach hurricane strength (74 mph, 64 knots or greater). And pressure drops associated with Arctic storms are small compared to ones in the tropics. More importantly, the impact of an atmospheric storm on the ocean and on the coast is entirely dependent on the season. If a large storm strikes during the winter or when the ocean is ice-covered, the storm will generate negligible waves and surge, and it will not generate erosion or coastal flooding. On the other hand, if a large storm strikes when the ocean is partially ice-covered (e.g., 50% covered), surge may be enhanced relative to an ice-free ocean, potentially leading to greater coastal flooding.more » « less
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Arctic storm surge events have a distinct character, and their impact on the coast is unique compared to a non-Arctic event. On the one hand, Arctic peak wind speeds rarely reach hurricane strength (74 mph, 64 knots or greater). And pressure drops associated with Arctic storms are small compared to ones in the tropics. More importantly, the impact of an atmospheric storm on the ocean and on the coast is entirely dependent on the season. If a large storm strikes during the winter or when the ocean is ice-covered, the storm will generate negligible waves and surge, and it will not generate erosion or coastal flooding. On the other hand, if a large storm strikes when the ocean is partially ice-covered (e.g., 50% covered), surge may be enhanced relative to an ice-free ocean, potentially leading to greater coastal flooding.more » « less
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Abstract Capes and cape‐associated shoals represent sites of convergent sediment transport, and can provide points of relative coastal stability, navigation hazards, and offshore sand resources. Shoal evolution is commonly impacted by the regional wave climate. In the Arctic, changing sea‐ice conditions are leading to (a) longer open‐water seasons when waves can contribute to sediment transport, and (b) an intensified wave climate (related to duration of open water and expanding fetch). At Blossom Shoals offshore of Icy Cape in the Chukchi Sea, these changes have led to a five‐fold increase in the amount of time that sand is mobile at a 31‐m water depth site between the period 1953–1989 and the period 1990–2022. Wave conditions conducive to sand transport are still limited to less than 2% of the year, however—and thus it is not surprising that the overall morphology of the shoals has changed little in 70 years, despite evidence of active sand transport in the form of 1‐m‐scale sand waves on the flanks of the shoals which heal ice keel scours formed during the winter. Suspended‐sediment transport is relatively weak due to limited sources of mud nearby, but can be observed in a net northeastward direction during the winter (driven by the Alaska Coastal Current under the ice) and in a southwestward direction during open‐water wind events. Longer open‐water seasons mean that annual net northeastward transport of fine sediment may weaken, with implications for the residence time of fine‐grained sediments and particle‐associated nutrients in the Chukchi Sea.more » « less
- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1029/2024EA003803
