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    • Sea Level Rise: American Samoa: High-Tide Flooding: 2080 Intermediate Scenario

    Metadata Updated: August 26, 2024

    This high-tide flooding layer provides a prediction of future sea level rise (SLR) inundation and was produced using a passive flooding model, often referred to as a "bathtub" model. It provides an assessment of flooded areas according to a specific water level. These water levels are determined using projections from the U.S. Interagency Task Force (ITF) (Sweet et al., 2022) in combination with land subsidence projections modeled by Han et al. (2019). The latter is included only for Tutuila, Aunuu, and Manua Islands (Ofu, Olosega, and Tau). In contrast, SLR projections for Swains Island and Rose Atoll only include the climate-related processes (ITF). The projections are modeled following both scenarios and time. The five scenarios range from low to high depending on the amount of greenhouse gases emissions, while time is divided by decade from 2030 to 2100.

    We apply this model to the 2022 National Geodetic Survey (NGS) lidar DEM for American Samoa with 1-meter resolution. The DEM was leveled from NAD83 (PA11) to mean sea level at 0 m (MSL=0) in 2005. The adjustment of the DEM may lead to inaccuracies due to the lack of historic information. It is also important to acknowledge that any inaccuracies in the DEM will lead to inaccuracies in the flooding estimates.

    In the 2080 intermediate scenario represented here, the modeled water level is 92 cm (56 cm for Rose and Swains). In this scenario, world-wide society continues current emissions rates, and sea level rises at increased rates compared to the intermediate-low scenario. Tipping points, i.e. large and sudden changes, are still not crossed. It is recommended using this scenario for planning construction of infrastructure with low-to-medium critical use and lifespans extending into the second half of the century, such as a new storefront.

    Flood depth is provided in centimeters above the 2005 mean higher high water (MHHW) tide level.

    It is essential to emphasize that the passive flooding model used to produce this data layer does not include the effects of waves on flooding. As a result, the extent and impacts of future flooding under high-wave conditions are not represented, which should be accounted for in planning efforts. In addition, the DEM is assumed to be unchanged as sea level rises, but in fact there will be erosion and changes in the shape of the land surface, and continued subsidence. This also must be considered, and it is best practice to consider any flooding extent or depth represented in this data layer as a best-case scenario, with the effects of dynamic shoreline processes leading to greater flood extent and depth than presented.

    Access & Use Information

    License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

    Downloads & Resources

    Dates

    Metadata Date July 31, 2024
    Metadata Created Date August 26, 2024
    Metadata Updated Date August 26, 2024
    Reference Date(s) July 31, 2024 (creation), July 31, 2024 (issued), July 31, 2024 (revision)
    Frequency Of Update

    Metadata Source

    Harvested from ioos

    Other Data Resources

    Graphic Preview

    Sample image.

    Additional Metadata

    Resource Type Dataset
    Metadata Date July 31, 2024
    Metadata Created Date August 26, 2024
    Metadata Updated Date August 26, 2024
    Reference Date(s) July 31, 2024 (creation), July 31, 2024 (issued), July 31, 2024 (revision)
    Responsible Party University of Hawaii at Manoa (Point of Contact)
    Contact Email
    Guid as_uhslc_all_slr_flood_2080_int_v2
    Access Constraints
    Bbox East Long -168.140850541878
    Bbox North Lat -11.0480017523415
    Bbox South Lat -14.559769090829
    Bbox West Long -171.089797256602
    Coupled Resource [{"title": [], "href": ["#DataIdentification"], "uuid": []}, {"title": [], "href": ["#DataIdentification"], "uuid": []}, {"title": [], "href": ["#DataIdentification"], "uuid": []}]
    Frequency Of Update
    Graphic Preview Description Sample image.
    Graphic Preview File http://pacioos.org/metadata/browse/as_uhslc_all_slr_flood_2080_int_v2.png
    Harvest Object Id 13e0dfcc-3a03-4051-acfc-21fcedfc46ab
    Harvest Source Id 54e15a6e-6dde-4c9c-a8f0-345cc0dfccfb
    Harvest Source Title ioos
    Licence
    Lineage 2023-09-26T00:00:00Z Initial release (Version 1.0). 2024-07-31T00:00:00Z Data Update (Version 2.0): For improved accuracy, sea level rise inundation was recalculated using a newly released higher resolution digital elevation model (DEM) as its basis. Version 1.0 used a 2021 DEM with 1/9 arc-second resolution, except for Rose Atoll where a 2012 DEM with 1/3 arc-second resolution was used (NOAA/CIRES CUDEM). In contrast, Version 2.0 uses a NOAA National Geodetic Survey (NGS) 2022 lidar DEM with 1-meter resolution. Swains Island is now included in the Verison 2.0 results, but it and Rose Atoll do not include vertical land motion (VLM) in their estimates. All DEMs were leveled to mean sea level at 0 m (MSL=0) in 2005.
    Metadata Language eng
    Metadata Type geospatial
    Old Spatial {"type": "Polygon", "coordinates": [[[-171.089797256602, -14.559769090829], [-168.140850541878, -14.559769090829], [-168.140850541878, -11.0480017523415], [-171.089797256602, -11.0480017523415], [-171.089797256602, -14.559769090829]]]}
    Progress
    Spatial Data Service Type Open Geospatial Consortium Web Feature Service (WFS)
    Spatial Reference System
    Spatial Harvester True

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