Monitoring Strong Tidal Currents
in Straits and Nearshore Regions
Alexei Sentchev, Max Yaremchuk and Maxime Thiébaut
Introduction
Open-ocean currents flow in complex patterns affected by wind, water density
gradients, topography of the ocean floor, and the Earth’s rotation. These large scale
and relatively slow evolving forcing terms create water motions that are relatively
persistent in magnitude and direction. In contrast, near-shore currents exhibit much
stronger magnitude and variability both in space and time. Near the boundaries, in
shallow water regions, and in narrow straits, flow dynamics is increasingly complex: tides and tidal currents are amplified, stratification effects are more pronounced, wind driven flows can contribute to extremely large variation of the sea
level, while frictional effects in strong currents result in complex turbulent motions.
The strongest currents that can be experienced in coastal regions have tidal
origin. Near the coast, tidal dynamics can be considerably modified by the shallow
water and the coastline, and tidal current speed attains values of several meters per
second that open ocean currents never reach. Regions of such high-tidal current
speeds are sparse, and are typically the result of topographic flow amplification.
A fast moving tide passing through a constriction can result in a tidal race (extremely strong current). It can also give rise to the formation of waves, eddies, and
hazardous currents. In extreme cases, such as in Skookumchuck Narrows in British
Columbia, through which tides can travel at more than 17 knots, very large
whirlpools develop, which can be extremely hazardous to navigation. In other
A. Sentchev ( ✉ ) ⋅ M. Thiébaut
Lab. Oceanography and Geosciences, UMR 8187, LOG,
Université du Littoral - Côte d’Opale, CNRS, Université de Lille, Wimereux, France
e-mail: alexei.sentchev@univ-littoral.fr
M. Yaremchuk
Naval Research Laboratory, Stennis Space Center, Hancock, USA
e-mail: max.yaremchuk@nrlssc.navy.mil
© Springer International Publishing AG, part of Springer Nature 2018
M. G. Velarde et al. (eds.), The Ocean in Motion, Springer Oceanography,
https://doi.org/10.1007/978-3-319-71934-4_33
519
in Straits and Nearshore Regions
Alexei Sentchev, Max Yaremchuk and Maxime Thiébaut
Introduction
Open-ocean currents flow in complex patterns affected by wind, water density
gradients, topography of the ocean floor, and the Earth’s rotation. These large scale
and relatively slow evolving forcing terms create water motions that are relatively
persistent in magnitude and direction. In contrast, near-shore currents exhibit much
stronger magnitude and variability both in space and time. Near the boundaries, in
shallow water regions, and in narrow straits, flow dynamics is increasingly complex: tides and tidal currents are amplified, stratification effects are more pronounced, wind driven flows can contribute to extremely large variation of the sea
level, while frictional effects in strong currents result in complex turbulent motions.
The strongest currents that can be experienced in coastal regions have tidal
origin. Near the coast, tidal dynamics can be considerably modified by the shallow
water and the coastline, and tidal current speed attains values of several meters per
second that open ocean currents never reach. Regions of such high-tidal current
speeds are sparse, and are typically the result of topographic flow amplification.
A fast moving tide passing through a constriction can result in a tidal race (extremely strong current). It can also give rise to the formation of waves, eddies, and
hazardous currents. In extreme cases, such as in Skookumchuck Narrows in British
Columbia, through which tides can travel at more than 17 knots, very large
whirlpools develop, which can be extremely hazardous to navigation. In other
A. Sentchev ( ✉ ) ⋅ M. Thiébaut
Lab. Oceanography and Geosciences, UMR 8187, LOG,
Université du Littoral - Côte d’Opale, CNRS, Université de Lille, Wimereux, France
e-mail: alexei.sentchev@univ-littoral.fr
M. Yaremchuk
Naval Research Laboratory, Stennis Space Center, Hancock, USA
e-mail: max.yaremchuk@nrlssc.navy.mil
© Springer International Publishing AG, part of Springer Nature 2018
M. G. Velarde et al. (eds.), The Ocean in Motion, Springer Oceanography,
https://doi.org/10.1007/978-3-319-71934-4_33
519