Research On Surface Current Detection And Deep Current Inversion By Using Ground Wave Radar

More than 70% of the Earth’s surface area is covered with water. Water resources and its space environment are closely related to the survival and development of human being. As the society develops, Humans depend more and more on water. Therefore, the utilization of water resources, the monitoring and controlling of water environment are becoming more and more important. With the continuous developments of scientific technology and water resources discipline, water observation methods have been constantly improved and enhanced. Developing during the recent 30 years, the Non-contact measuring technology represented by Radar Remote Sensing is more advanced, compared with the traditional Direct-contact measurement. The method of radar remote sensing measurement has good quality of mobility, flexibility and real-time. With the minimum measuring cost, it can achieve the maximum detection efficiency and the widest covering range of detection. With the advantage that it would not touch the water’s edge during the measurements, it can be competent for any measurements of the surface hydrological information which was under complex geological and severe external weather conditions.HF ground wave radar, the representative of Non-contact measuring technology, can carry out the marine monitoring which can be remote, large area and all-weather real-time, and can detect wind, wave, current and some other physical elements of the marine as well. In recent years, China has increased its investment for the research of ocean observing systems and technology. Since 1987,Radio Propagation Lab. of Wuhan University have begun to study high-frequency radar system which was applied to monitor the sea-state, and also took up the National High Technology 863 Project——’Research of Portable High Frequency Ocean State Measurement and Analysis Radar. They have successfully developed the array-based radar-OSMAR200X which was used for the marine surface monitoring, and later developed a compact-antenna-array-based portable high-frequency surface wave radar:OSMAR-S. The researches mentioned above had successfully passed the appraisal of the Country’s Technological Achievements. They are significant achievements in the field of remote sensing monitoring of ocean surface. The laboratory has researched the marine remote sensing technology, and launched the research of river hydrological monitoring using radar remote sensing measurements.Then they successfully developed a three-channel UHFriver detection radar system.which has been experimented at the Yangzte river and got satisfactory results.As the electromagnetic wave attenuation in the water is very quick when we use remote sensing wave technology in the ocean, the detection technology of radar remote sensing of water environment is confined to the natural water surface. To find information about the water body, we have to use direct-contact measurement. The internal information of water can not be measured directly is the limitation and weaknesses of the radar remote sensing technology as the representative of non-contact measurement technology.According to the principle of fluid mechanics, there is some connection between the state of water surface and the environment of water body. The main purpose of this paper is to study the link between them and find out a technology which uses the surface water flow data from radar remote sensing to get the interior information of water body. Because Fluid mechanics theory has different forms in different water bodies, it is necessary to consider the specific research object,such as ocean and river, while studying the connection between the internal of the water body and the surface statement of water surface. This paper studied how the surface state parameters reflected the internal state parameters in two water body environment which include the ocean area detected by HF ground wave radar and the Yangtze River detected by ultra-high frequency ground wave radar. The main content of the thesis is as follows:1. The reliability and veracity of the OSMAR system is evaluated based on the contrast data of the ocean surface current from the handily-taken HFSWR. At the same time, the depth detected by the radar is contrasted and analyzed at the first time according to section detection.2.According to the features and related setting parameters of the sea current movement, the hydro-state equations fit the ocean movement are deduced based on the hydromechanical theory.3.A appropriate spatial 3D solid reseau is constructed based on the sea eare combine with feature of the data of sea current. The hydro-state equations are solved by finity-difference method with the sea current data provided by the HFSWR as the boundary condition. Then the result of the deep current is contrasted with the measured synchronous data.4. According to the features and related setting parameters of the river current movement, the hydro-state equations fit the river current movement are deduced based on the hydromechanical theory. Experiential formulas about the river current hydrological parameters are summarized.5. An approximate model of the appropriately selected riverway section is constructed based on the river condition combine with feature of the data of river current. The movement parameters of current inside the riverway section are calculated by selecting parameters appropriately Then the flux is calculated on the model of the riverway section. The results are also compared to the measured results.6.According to the data received by handily-taken HFSWR and the chosen ocean wave spectrum.The radar echo spectrum is simulated and then compared with the real spectrum. So the storm imformation of the ocean is deduced by the data fitting method.