University Of Tasmania

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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, JR
This 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.


Publication title

Natural Hazards








Institute for Marine and Antarctic Studies



Place of publication

Van Godewijckstraat 30, Dordrecht, Netherlands, 3311 Gz

Rights statement

Copyright 2012 Springer Science+Business Media B.V.

Repository Status

  • Restricted

Socio-economic Objectives

Climate variability (excl. social impacts)