Characteristics of ocean waves measured with shipborne wave meter.

Abstract

Wave observation data obtained with Tucker type shipborne wave meter in 1984, 1985 and 1986 were analysed with data processing method which was developed by Tokuda and Michida (1986). As the first step to clarify characteristics of waves in the open ocean, following investigations were made. 1) Analysed wave data were compared with wave data indicated in Ocean Wave Charts presented by JMA. 2) Regional mean values of the significant wave heights and periods were calculated. 3) Calculating the ratio of the significant wave height between the lee side and the weather side, relationships between the ratio and wind wave direction relative to the ship heading were examined. From above investigations, following results were obtained. 1) Ocean Wave Charts presented by JMA generally illustrate the real ocean conditions excepting a few cases when weather fronts happened to pass over the observation area. 2 ) In average, the significant wave heights are large in the region of the northern part of 30° N and that of the trade wind. On the other hand, they are small in the equatorial region and the area of the middle latitude. 3) The ratio of the wave height of the lee side to the weather side is the smallest in the case when wind waves come from the ship side.