Artificial Upwelling and Near-field Mixing of Deep-ocean Water Effluent

摘要

Deep-ocean water (DOW) at a depth of 300 m or lower is cold, nutrient-rich, and free of pathogenic bacteria. This water is considered an important natural resource. One of the fully developed technologies of DOW application is ocean thermal energy conversion (OTEC), which makes use of DOW for energy production. In recent years, the potential of DOW to enrich the open oceans and thus to increase fish yield has attracted the attention of researchers. Before this potential can be realized, however, major scientific and technological developments concerning artificial upwelling, plume mixing, and DOW stimulated bio-productivity must be achieved. This study, which is a continuation of earlier research on artificial upwelling at the University of Hawaii, investi- gates the effects of discharging artificially upwelled DOW into the open ocean where it is subsequently mixed with surface water. The study involves both hydraulic modeling and numerical simulation, and its objective is to control the near-field mixing of DOW effluent such that the dilution is small and the settling depth does not go below the euphotic zone. Special attention is given to wave effects on the near-field mixing processes. Research results indicate that, with proper effluent control, desirable nutrient-rich DOW plumes can be established and maintained in the open ocean.