Articles | Volume 13, issue 4
Research article
20 Jul 2017
Research article |  | 20 Jul 2017

The “shallow-waterness” of the wave climate in European coastal regions

Kai Håkon Christensen, Ana Carrasco, Jean-Raymond Bidlot, and Øyvind Breivik

Abstract. In contrast to deep water waves, shallow water waves are influenced by bottom topography, which has consequences for the propagation of wave energy as well as for the energy and momentum exchange between the waves and the mean flow. The ERA-Interim reanalysis is used to assess the fraction of wave energy associated with shallow water waves in coastal regions in Europe. We show maps of the distribution of this fraction as well as time series statistics from eight selected stations. There is a strong seasonal dependence and high values are typically associated with winter storms, indicating that shallow water wave effects can occasionally be important even in the deeper parts of the shelf seas otherwise dominated by deep water waves.

Short summary
In this note we investigate when and where we would expect the bottom to influence the dynamics of surface waves. In deep water, where the presence of the bottom is not felt by the waves, modelers can use a simpler description of wave-mean flow interactions; hence, the results are relevant for coupled wave-ocean modeling systems. The most pronounced influence is on the Northwest Shelf during winter, and can sometimes be significant even far from the coast.