Generation mechanisms of the water surface elevation induced by a moving atmospheric pressure disturbance

Abstract

Forced water wave by the moving atmospheric pressure disturbance (APD) is an important factor to cause sea surface elevation during meteorological disasters, whose generation mechanism is complicated and unclear. To this end, surface elevation induced by a moving APD is theoretically studied. Based on the present analytical solution, it is confirmed that the APD-induced surface elevation consists of three components with respect to different influence factors, including the initial surface elevation, the initial vibration trend and the external force. Surface elevation induced by its initial value or initial vibration trend composes of two waves propagating in opposite directions with the shallow water wave speed. Meanwhile, the external force produces two small waves propagating backward and forward at each time instant, and the surface elevation is the superposition of these two waves. Subsequently, contributions from the above three factors to the total surface elevation are specified. Along the APD center, the initial surface elevation plays a significant role at the beginning and its function decreases as time passing by, whereas contribution of the external force shows an opposite trend. Regarding other areas, effects of these three factors cancel each other out, leading to an inconspicuous surface elevation.