Oil Spill Pollution Monitoring At Sea Using Ship-borne HF Ground Wave Radar

As the development of economy and the progress of technology, there’s anincreasing demand for oil in people’s daily life. Global offshore oil exploration andtransportation enterprise are flourishing. At the same time, oil spill incident caused byoil and its refined products accidentally spilled into ocean during storage andtransportation, has become serious worldwide ocean pollution.High Frequency Ground Wave Radar (HFGWR) using vertical polarization highfrequency waves, has the feature of small energy attenuation when transmitting alongthe sea surface. It can detect targets beyond the range of visibility and has become animportant method for detection of low speed motion target and for remote sensing ofsea-state. In this paper, we discuss an oil spill monitoring method using ship-borneHFGWR.In this paper, we firstly analyze the signal processing process and informationextraction method of HFGWR, which is also the theoretical basis of sea-state remotesensing using HFGWR. Sea clutter environment is the main application background ofoil spill pollution using HFGWR, so we next discuss the first-order sea clutter theoryand its mechanism. In the order from general to specific, we analyze the sea cluttertheory of stationary platform at first and then the sea clutter spectrum spreadphenomenon of moving platform. On the basis of the theoretical analysis, we simulatethe first-order sea clutter model and demonstrate the simulation results under differentconditions.Then, starting from the first-order and second-order Radar Cross Section (RCS)equation put forward by Barrick, we discuss the extraction method of some sea-stateparameters, such as current velocity, wave height, wind speed on sea surface. Based onthis, we get the sea-state parameters extraction flow chart using HFSWR. In this paper,we detect and track the oil spill pollution zone through its velocity and the drift velocityof oil depends on wind speed and current velocity, so we do some detailed analysis tothese two important parameters and build the oil spill dynamic model according to oilspill drift and diffusion characteristics.In order to detect oil spill pollution zone and estimate the size of the pollution area,the oil spill monitoring includes two parts, the detection of oil spill zone and theextraction of its boundary. In the last chapter of this paper, we simulate the oil Dopplerspectrum in each situation under sea clutter background and illustrate the oil spillmonitoring results. When radar detects only oil echo or sea echo in some certain range,we can tell from the echo spectrum whether there’s an oil spill incident. But when radardetects both oil echo and sea echo, whether or not we can extract the boundary of the oilslick depends on the velocity of sea current and the radar platform. If the velocity is relatively low, we can get the boundary information and estimate the size of oil spillpollution.