Application of Ensemble Kalman Filter Data Assimilation Method in Tide Simulation and Prediction in the Taiwan Strait

In order to improve the accuracy of numerical simulation,a numerical model of tide with an Ensemble Kalman Filter(EnKF) data assimilation technique is established.In this article we take into account 5 stations,which are Dongshan,Xiamen,Nianggong, Chongwu,Sansha.The data assimilated in the model is from the book of 2009 Tide Table.In order to decide EnKF the best combination of two parameters,which are the cut radius and ensemble number,we consider 42 kinds of parameter combinations at each station.Based on the accuracy of numerical simulation and the time spent in calculating the same period of tide,we can define the best parameter combination at each station.Numerical experiments show that the best value of cut radius is 35 km for Dongshan,Xiamen, Nianggong and Chongwu stations,and the best value of cut radius is 30 km for Sansha station.The unique best value of ensemble number for 5 stations is 20.It can be seen from numerical experiments that data assimilation with EnKF method can improve the accuracy of tide simulations and tide predictions in the following 12 hours in the Taiwan Strait.