Study On The Refinement And Application Of Ocean Tidal Model In The Local Waters

Tidal is one of the most common phenomenon in the ocean.Its precise information is a basis of all the activities of sea.Although the tidal station on the offshore and nearby islands can provide the observation data,considering the uncertainty of datum and the uncontrollable range of tidal station far away from coastal,and the ocean tidal model studied more and more hot,this paper would like obtain the accurate tidal with the help of ocean tidal model.However,in China's coastal,vast water area,large water depth variation,more variety of sea-bed terrain,many distribution of tidal wave,complexity of dynamic process,and much shallow waters,the strong influence of ocean dynamic and land reflection,and a few of tidal data of China' costal,etc,the accuracy of ocean tidal model in the sea of China is the focus of attention.Many scholars of China has been validated its precision and some others has been built a new model based on the assimilating method.But there is little study on the refinement of the existed models.Therefore,this paper studies on the refinement of ocean tidal model in local waters,and the application of refinement models.The main work and contributions of this dissertation are as follows:1)Introduces the development and the existed situation of ocean tidal model according to some bibliography.Further declares the necessary of refinement tidal model in the China's sea based on the need of practical engineering.2)To acquire the higher precision of tidal components,the theory of tidal analysis and two of methods are introduced.There are the least square and spectral analysis based on FFT.On the basis of precision of two methods,and the result of t-tide,the method of the least square is better than FFT,which plays role in the latter tidal analysis and the tidal model rcfinemend.3)Two methods of verification of precision about ocean tidal model are presented.And with the accordance with this precision,process of refinement of tidal model is determined to do or not.This paper proposed three methods of refinement,included that method of difference ratio relations between tidal components,method of differential cosine and sine component between tidal station and tidal model,method of the best tidal component recombination.This paper also introduces distinction and data processing model of each method.4)To obtain the credible and high quality tidal height,studying the application of the refinement tidal model in the given waters.The application are mainly containing law of tidal wave propagation by tidal height difference and time difference,the layout of tidal station,the unified and harmony determination of mean sea level and the depth datum,tidal level control,and the final tidal reckoning.5)The methods proposed by this paper are validated by 5 tidal models,the results show that the method of based on differential between the value of the long-term tidal station and the tidal model is the best of 3 methods in precision.According to this,studying the application of the refinement model.It can reflect the type of tidal objectively,and sustain the application of tidal model in the ocean engineering.