Tidally induced mean flow over bathymetric features: a contemporary challenge for high-resolution wide-area models

Huthnance [Estuarine CoastalMar. Sci. 1973, 1, 89–99] is reviewed, whereby an oscillating tide over bathymetric features induces a mean flow generally along isobaths. The effect is a superposition of Coriolis and frictional processes. These are discussed with the intention of elucidating the processes for a more general readership. Induced velocities of order several cm/s are expected around the UK shelf seas. The effect is dynamically significant over bathymetric scales of order a few kilometres and has previously been of most interest to dynamicists studying processes on this scale. However, with the increase in computing power, appropriate scales can be simulated in shelf-wide regional models and in next generation operationalmodels. It is demonstrated that this small-scale effect is likely to be important for shelf-wide regionalmodels and that a spatial resolution of at least 1.8km is recommended for shelf sea simulations.