In order to determine the design tide levels in the areas without measured tide level data, especially in the areas where it is difficult to measure tidal levels, a calculation method based on a numerical model of tid...In order to determine the design tide levels in the areas without measured tide level data, especially in the areas where it is difficult to measure tidal levels, a calculation method based on a numerical model of tidal current is proposed. The essentials of the method are described, and its application is illustrated with an example. The results of the application show that the design tide levels calculated by the method are close to those determined by long-time measured tide level data, and its calculation precision is high, so it is feasible to use the method to determine the design tide levels in the areas.展开更多
In this paper, the numerical modelling of the tidal level and current in the Bohai Sea was carried out with ADI method, by taking the sum of four main tidal components M2,S2K2,O1 as the open boundary condition. The ca...In this paper, the numerical modelling of the tidal level and current in the Bohai Sea was carried out with ADI method, by taking the sum of four main tidal components M2,S2K2,O1 as the open boundary condition. The calculated values were consistent with the predicted ones (the observed values in the case of calm) in the Tidal Table. On the basis of the modelling of the tide, the sea level and current fields under the effects of strong wind were simulated. The calculated results were also quite satisfactory.展开更多
Back propagation is employed to forecast the current of a storm with various characteristics of storm surge; the technique is thus important in disaster forecasting. One of the most fuzzy types of information in the p...Back propagation is employed to forecast the current of a storm with various characteristics of storm surge; the technique is thus important in disaster forecasting. One of the most fuzzy types of information in the prediction of geological calamity is handled employing the information diffusion method. First, a single-step prediction model and neural network prediction model are employed to collect influential information used to predict the extreme tide level. Second, information is obtained using the information diffusion method, which improves the precision of risk recognition when there is insufficient information. Experiments demonstrate that the method proposed in this paper is simple and effective and provides better forecast results than other methods. Future work will focus on a more precise forecast model.展开更多
Based on linear poroelasfic and hydrogeology theory, a mathenmatical expression describing the relationship between water level clmnge and aquifer volume strain is put forward. Combined with earth tidal theory, we ana...Based on linear poroelasfic and hydrogeology theory, a mathenmatical expression describing the relationship between water level clmnge and aquifer volume strain is put forward. Combined with earth tidal theory, we analyze the response characteristics from well-aquifer water level change to earth tide of volume strain and present a method of volume strain inversion from water level clmnge. Comparing the results of inversion with real observed data, we found that there is a good consistency. This suggests that the method of volume strain inversion from water level clmnge is proper. It will offer a reference for learning about hydrogeology characteristics, volume strain and searching for precursor anomalies.展开更多
The tide level displays information about the state of the sea current and the tidal motion. The tide level of the southern coast of Japan Island is affected strongly by Kuroshio Current flowing in the western part of...The tide level displays information about the state of the sea current and the tidal motion. The tide level of the southern coast of Japan Island is affected strongly by Kuroshio Current flowing in the western part of North Pacific Ocean. When Kuroshio takes the straight path and flow along the Japan Islands, the tide level increases, and it is calculated from two tide level data observed at Kushimoto and Uragami in the southern part of Kii Peninsula. In contrast, the tide level decreases at the time when Kuroshio leaves from the Japan Islands. In this paper, the hourly tidal data are analyzed using the Autocorrelation Function (ACF) and the Mutual Information (MI) and the phase trajectories at first. We classify the results into 5 types of tidal motion. Each categorized type is investigated and characterized precisely using the mean tide level and the unit root test (ADF test) next. The frequency of the type having unstable tidal motion increases when the Kuroshio Current is non-meandering or in a transition state or the tide level is high, and the type shows a non-stationary process. On the other hand, when the Kuroshio Current meanders, the tidal motion tends to take a periodical and stable state and the motion is a stationary process. Though it is not frequent, we also discover a type of stationary and irregular tidal motion.展开更多
基金The National Key Fundamental Research and Development Program ("973" Program) of China under contract No. 2010CB429001
文摘In order to determine the design tide levels in the areas without measured tide level data, especially in the areas where it is difficult to measure tidal levels, a calculation method based on a numerical model of tidal current is proposed. The essentials of the method are described, and its application is illustrated with an example. The results of the application show that the design tide levels calculated by the method are close to those determined by long-time measured tide level data, and its calculation precision is high, so it is feasible to use the method to determine the design tide levels in the areas.
文摘In this paper, the numerical modelling of the tidal level and current in the Bohai Sea was carried out with ADI method, by taking the sum of four main tidal components M2,S2K2,O1 as the open boundary condition. The calculated values were consistent with the predicted ones (the observed values in the case of calm) in the Tidal Table. On the basis of the modelling of the tide, the sea level and current fields under the effects of strong wind were simulated. The calculated results were also quite satisfactory.
基金Supported by the MISSION 908 (Nos. 908-02-03-07, SD-908-02-08)
文摘Back propagation is employed to forecast the current of a storm with various characteristics of storm surge; the technique is thus important in disaster forecasting. One of the most fuzzy types of information in the prediction of geological calamity is handled employing the information diffusion method. First, a single-step prediction model and neural network prediction model are employed to collect influential information used to predict the extreme tide level. Second, information is obtained using the information diffusion method, which improves the precision of risk recognition when there is insufficient information. Experiments demonstrate that the method proposed in this paper is simple and effective and provides better forecast results than other methods. Future work will focus on a more precise forecast model.
基金The researchwas jointly supported by the research project entitled"Research on the Digital Data Analysis Application of Underground Fluid"under the 11th"Five-Year Plan"of China Earthquake Administration (2006BAC01B02-03-02)the Joint Earthquake Science Foundation of China Earthquake Administration (105141)
文摘Based on linear poroelasfic and hydrogeology theory, a mathenmatical expression describing the relationship between water level clmnge and aquifer volume strain is put forward. Combined with earth tidal theory, we analyze the response characteristics from well-aquifer water level change to earth tide of volume strain and present a method of volume strain inversion from water level clmnge. Comparing the results of inversion with real observed data, we found that there is a good consistency. This suggests that the method of volume strain inversion from water level clmnge is proper. It will offer a reference for learning about hydrogeology characteristics, volume strain and searching for precursor anomalies.
文摘The tide level displays information about the state of the sea current and the tidal motion. The tide level of the southern coast of Japan Island is affected strongly by Kuroshio Current flowing in the western part of North Pacific Ocean. When Kuroshio takes the straight path and flow along the Japan Islands, the tide level increases, and it is calculated from two tide level data observed at Kushimoto and Uragami in the southern part of Kii Peninsula. In contrast, the tide level decreases at the time when Kuroshio leaves from the Japan Islands. In this paper, the hourly tidal data are analyzed using the Autocorrelation Function (ACF) and the Mutual Information (MI) and the phase trajectories at first. We classify the results into 5 types of tidal motion. Each categorized type is investigated and characterized precisely using the mean tide level and the unit root test (ADF test) next. The frequency of the type having unstable tidal motion increases when the Kuroshio Current is non-meandering or in a transition state or the tide level is high, and the type shows a non-stationary process. On the other hand, when the Kuroshio Current meanders, the tidal motion tends to take a periodical and stable state and the motion is a stationary process. Though it is not frequent, we also discover a type of stationary and irregular tidal motion.
