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Extreme surface and near-bottom currents in the northwest Atlantic
journal contribution
posted on 2023-05-17, 16:10 authored by Oliver, ECJ, Sheng, J, Thompson, KR, Urrego Blanco, JRThis study presents a methodology for estimating extreme current speeds from numerical model results using extremal analysis techniques. This method is used to estimate the extreme near-surface and near-bottom current speeds of the northwest Atlantic Ocean with 50-year return periods from 17 years of model output.The non-tidal currents produced by a threedimensional ocean circulation model for the 1988–2004 period were first used to estimate and map the 17-year return period extreme current speeds at the surface and near the bottom. Extremal analysis techniques (i.e., fitting the annualmaxima to the Type I probability distribution) are used to estimate and map the 50-year extreme current speeds. Tidal currents are dominant in some parts of the northwest Atlantic, and a Monte Carlo-based methodology is developed to take into account the fact that large non-tidal extrema may occur at different tidal phases. The inclusion of tidal currents in this way modifies the estimated 50-year extreme current speeds, and this is illustrated along several representative transects and depth profiles. Seasonal variations are examined by calculating the extreme current speeds for fall-winter and spring–summer. Finally, the distribution of extreme currents is interpreted taking into account (1) variability about the time-mean current speeds, (2) wind-driven Ekman currents, and (3) flow along isobaths.
History
Publication title
Natural HazardsVolume
64Pagination
1425-1446ISSN
0921-030XDepartment/School
Institute for Marine and Antarctic StudiesPublisher
SpringerPlace of publication
Van Godewijckstraat 30, Dordrecht, Netherlands, 3311 GzRights statement
Copyright 2012 Springer Science+Business Media B.V.Repository Status
- Restricted