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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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Morphology and Sediment Dynamics of Blossom Shoals at Icy Cape, Alaska
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.
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- PAR ID:
- 10501479
- Publisher / Repository:
- American Geophysical Union
- Date Published:
- Journal Name:
- Journal of Geophysical Research: Earth Surface
- Volume:
- 129
- Issue:
- 4
- ISSN:
- 2169-9003
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Observations of ocean surface waves at three sites along the northern coast of Alaska show a strong correlation with seasonal sea ice patterns. In the winter, ice cover is complete, and waves are absent. In the spring and early summer, sea ice retreats regionally, but landfast ice persists near the coast. The landfast ice completely attenuates waves formed farther offshore in the open water, causing up to a two‐month delay in the onset of waves near shore. In autumn, landfast ice begins to reform, though the wave attenuation is only partial due to lower ice thickness compared to spring. The annual cycle in the observations is reproduced by the ERA5 reanalysis product, but the product does not resolve landfast ice. The resulting ERA5 bias in coastal wave exposure can be corrected by applying a higher‐resolution ice mask, and this has a significant effect on the long‐term trends inferred from ERA5.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1029/2023JF007398
