Tide Height Estimation on Southern Coast of Java Island by Ensemble Kalman Filter

Tide is important things to discuss, especially for maritime countries such as Indonesia. The main purpose of tide observations is to determine the tide height on coast. In this study, data assimilation method, Ensemble Kalman Filter (EnKF), is applied to tide estimation. The location of this study is on the southern coast of Java Island which is located between Cilacap's tide station and Pacitan's tide station. The value of tide height on another tide station can be obtained with determination specific grid. In the estimation process, measurement data is used in correction step. Based on the results of simulation, the average error between EnKF and the measurement data from tide stations is 2,4535 cm or about 0,2113% with 100 ensemble. Because the simulation results show small error value, the value of tide height at the other point of tide station can be obtained. Therefore, it can be obtained information that not the highest or lowest height of the wave that occurred at the beginning, the end and the middle of the month in Hijri calendar. But the large amplitude of wave that happened at that time. So with a large amplitude, high and low waves can be generated at once.