Ocean Nutrient Enhancer "TAKUMI" is a SPAR type floating structure with a riser pipe. "TAKUMI" was installed in the Sagami Bay in May 2003 and is also working now. "TAKUMI" has some measurement equipments for oceanographic observation such as wave height meters and wind sensor. Furthermore, DGPS, gyroscope and accelerometers are installed to measure the motions of "TAKUMI". By using these measured data, the authors carried out estimation the wave condition around "TAKUMI". This estimated result was compared with statistical data.
Ocean Nutrient Enhancer "TAKUMI" is a SPAR type floating structure with a riser pipe. By pumping up the Deep Ocean Water containing rich nutrient, and sprinkling near the sea surface, plankton is made to increase and it aims to form a good fishing ground. "TAKUMI" was installed in the Sagami Bay in May 2003 and is also working now. "TAKUMI" has some measurement equipments for oceanographic observation such as wave height meters and wind sensors. Furthermore, DGPS, gyroscope and accelerometers are installed to measure the motion of floating structure. The authors estimated the wave condition around "TAKUMI" using these measured data. Though many researchers had proposed the analysis method of multidirectional irregular wave by using actual sea data, for example, Maximum Likelihood Method (Hirayama, et al., 1985), Bayesian estimation method (Iseki and Ohtsu, 1994), Parametric method (Yoshimoto and Watanabe, 1994), Nonlinear Programming method (Maeda, et al., 2002) and so on. These estimation methods had some problems, such as it needed complex parameters, it needed enormous calculation time, and its solution could not converge once in a while. Therefore, in this paper, the authors focused on estimation 6 parameters, which are main wave direction, significant wave height, and mean wave period of wind-wave and swell by using an simplified estimation method based on nonlinear programming method.
