A Study on Wave-Induced Artificial Upwelling

摘要

Artificial upwelling, a general technique to enhance the marine primary productivity and fishery resources by means of pumping the nutrient-rich deep ocean water (DOW) to the euphotic layer, has attracted great attention in recent years. One of the most practical methods of artificial upwelling is utilizing ocean waves. In this article, the wave-induced method, which can induce artificial upwelling immediately without external power, is discussed. This method is based on the Bernoulli equation of the small amplitude wave and utilizes a floating structure. The upwelling water head of the nonlinear characteristics in the wave motion is calculated, which is deduced by linear wave theory. This method predicts and estimates the upwelling flow rate, which is determined by the water head difference induced by waves. For example, when the sea depth is 100 m with an ideal regular progressive wave of 5 m in height and 0.1 Hz in frequency under an ideal condition, it could produce a 2,200 m3/h flow rate upwelling. However, in the real sea field, the efficiency of floating structure upwelling declined due to the increase of actual resistance.