Estimation of multi-modal directional wave spectra from tri-orthogonal measurements

In this paper a technique is discussed for analyzing multi-modal directional wave spectra from tri-orthogonal measuring methods. The technique is illustrated for measurements, made with a three-dimensional acoustic current meter in the southern part of the North Sea. The examples given are discussed in the light of the meteorological situation prior to and during the time of recording. The method can be used for the separation of sea and swell, which is of importance for the calculation of wave loads on structures as will be shown finally.