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Jeux de données / Pacific Islands Ocean Observing System (PacIOOS)

Sea Level Rise: American Samoa: High-Tide Flooding: 2070 High Scenario

Niveau marin

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 higher high water at 0 m (MHHW=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 2070 high scenario represented here, the modeled water level is 127 cm (93 cm for Rose and Swains). In this scenario, world-wide society continues to increase emissions. Tipping points (large and sudden changes) are triggered, and worst-case possibilities arise. It is recommended using this scenario for planning construction of infrastructure with highly critical use and longer lifespans, such as a new hospital.

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.

Données et ressources

Informations supplémentaires

Date (creation)2023-09-26
Date (issued)2023-09-26
Date (revision)2026-08-14
StatutonGoing
Fréquence de mise à jourasNeeded
Langue des métadonnéesen
LicenceThis data layer provides a scientific prediction of potential future conditions from flooding due to sea level rise. The methodology is based on published, peer-reviewed techniques. However, as with any forecast, accuracy cannot be guaranteed and actual impacts may vary from these predictions. While considerable effort has been made to implement all components in a thorough, correct, and accurate manner, errors are still possible. The results are provided without warranty of any kind. The risks associated with use or non-use of the results are assumed by the user. The data may be used and redistributed for free but is not intended for legal use, since it may contain inaccuracies. Neither the data Contributor, University of Hawaii, PacIOOS, NOAA, State of Hawaii nor the United States Government, nor any of their employees or contractors, makes any warranty, express or implied, including warranties of merchantability and fitness for a particular purpose, or assumes any legal liability for the accuracy, completeness, or usefulness, of this information.
Métadonnées sourcesISO 19115 XML
Dernière mise à jour2026-11-04
Créé2026-11-04
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