Open AccessOn the modification of tides in shallow water regions by wind effects
Author(s) -
Jones J. Eric,
Davies Alan M.
Publication year - 2008
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2007jc004310
Subject(s) - surge , storm surge , geology , waves and shallow water , wind stress , water level , magnitude (astronomy) , climatology , oceanography , environmental science , atmospheric sciences , storm , geomorphology , physics , cartography , astronomy , geography
The influence of non‐linear effects upon tides in shallow coastal regions, due to the presence of a significant storm surge is examined using a two‐dimensional model of the west coast of Britain. The model has an unstructured grid, designed to have a high resolution mesh in the near coastal region of the eastern Irish Sea, the area chosen as the focus of this study. The influence of tide‐surge interaction upon the M 2 , M 4 and M 6 components of the tide, due to surges produced by steady uniform wind stresses is examined in detail. Calculations show that in deep regions the tide is unaffected by the surge. However, in shallow coastal regions there is significant modification of tidal elevations and currents. This arises because of changes in bottom stress, and the non‐linear interaction term in the hydrodynamic equations. In addition the locations of regions that “wet and dry” are changed during the tidal cycle due to the influence of the surge. This gives rise to significant spatial variations and changes in magnitude of the tide and its higher harmonics depending upon wind stress direction and water depth. These results explain why tidal energy remains in the surge residual in shallow water when it is computed by de‐tiding the total signal using a tide only calculation; an effect often found in observed surge residuals.