The Generation of Long Shelf Waves by the Wind

Currents [O(0.1 m sec−1)] and sea-level variations [O(0.1 m)] on the continental shelf can be produced when atmospheric disturbances pass by. Since the atmospheric systems have length scales large compared with the width of the shelf, a boundary-layer approximation can be made to the equations governing the local response to these forcing systems. The low-frequency response can be expressed as a sum of modes (continental shelf waves) and the amplitude of each mode is found to satisfy a first-order wave equation which can readily be solved. In a case where some details are worked out, the second mode's contribution to sea-level changes is only 25% of the first mode's and the third mode's contribution only 8%. Thus, given appropriate meteorological information, sea level changes can easily be calculated, and a prediction system is theoretically possible.