MEASUREMENT OF THE VELOCITY-PROFILE IN AND ABOVE A FOREST OF LAMINARIA-HYPERBOREA

The aim of this study is to resolve the mechanism of damping of surfac e waves above bottom vegetation. A field experiment has been carried o ut, where the horizontal velocities were measured in and above a kelp forest of Laminaria hyperborea (GUNNERUS)Foslie, using ultrasonic curr ent-meters. The results from the experiment are presented as periodogr ams of kinetic energy-density at several levels, and as the correlatio n of energy at two levels. The main conclusion is that the attenuation extends throughout the whole water column. The long waves exhibit onl y a slight (5-8%) reduction of velocity-amplitude within the kelp fore st.