Conditions for the occurrence of notable edge waves due to atmospheric disturbances

Abstract

It has been observed and theoretically proved that edge waves can be generated by a moving atmospheric pressure disturbance near the coast. This study aims to clarify the necessary conditions for the occurrence of significant edge waves associating with moving atmospheric pressure disturbances. The complex physical problem is simplified as a pressure disturbance moving along a coast with a constant beach slope. The dominant factors include the spatial scale and translational speed of disturbance, the beach slope, as well as the transient response of water surface. The effects of each factor are discussed based on numerical modeling. It is found that the quasi-steady wave pattern is controlled by two non-dimensional parameters, the ratio of the disturbance spatial scale to the wave length of fundamental edge wave and the ratio of the disturbance spatial scale to the distance from the center of disturbance to shoreline. The duration of atmospheric disturbance or the growth time of edge wave is also found to play an important role in the occurrence of notable edge waves. Starting from a calm sea, the growth of edge wave can be divided into a fast growth stage and a quasi-steady stage. The duration of the fast growth stage is affected by the spatial scale and the beach slope. When the fundamental mode of edge wave is dominant, the appearance of a notable edge wave is affected by the translational speed and the beach slope.