| Oil spill pollution is one of the most common marine pollution.With the rapid development of marine transportation and oil exploitation,oil spill pollution is becoming more and more serious,which poses a great threat to the marine environment and ecological balance.Therefore,the treatment and improvement of oil spill pollution has become an urgent and important work in marine environmental protection engineering.The key and premise of oil spill pollution control is to locate,identify and monitor the oil spill.Marine laser induced fluorescence(LIF)detection technology is considered as one of the most important and effective methods for oil spill monitoring because of its high sensitivity,good selectivity,fast real-time and other characteristics.At present,most of the researches based on laser fluorescence remote sensing are focused on the monitoring of non emulsified oil spill,but there is no relevant research on emulsified oil spill,which is an important form of oil spill on the sea.Emulsion oil spill will bring more harm to the marine environment,so how to realize the qualitative description and degree identification of emulsion oil spill on the sea,that is,to quickly and accurately give the spectral analysis data of emulsion oil spill,to meet the needs of the detection of emulsion oil spill based on LIF,has an important role and significance.In view of this,the main research work of this dissertation is as follows:Firstly,the principle of LIF detecting oil spill on the sea surface is described.This dissertation mainly discusses its advantages from the composition and fluorescence mechanism of the spilled oil.On the one hand,a large number of aromatic hydrocarbons in the spilled oil provide material basis for monitoring and identification;on the other hand,when the laser with certain wavelength and energy irradiates,the compounds can be excited with longer wavelength fluorescence.Finally,the feasibility of using fluorescence spectrum to identify and analyze oil pollutants is determined,which provides the basis for the follow-up research.Secondly,the indoor simulation of emulsified oil spill on the sea surface is carried out,and its spectral characteristics are analyzed.The oil-water emulsion samples with different oil-water ratio and depth and their spectra were obtained through experiments.Establish perfect spectral experimental data,clarify the spectral change rule of emulsified and non emulsified spills,and analyze the fine spectral response characteristics of different types of oil-water emulsions in detail.And the variation trends of fluorescence intensity,Raman intensity and fluorescence peak position with depth and oil-water ratio are obtained from the analysis of experimental data.Then,the identification study of the emulsified oil spill on the sea surface was carried out.It includes the distinction between emulsification and non emulsification,the distinction between different stages of emulsification and the combination of emulsification and oil classification.According to the spectral characteristics and change rules of emulsification and non-emulsification obtained in the previous study,the emulsified oil spill identification method is studied: one is the identification method combining spectral feature parameter and cluster analysis,and the other is principal component analysis.Recognition method combined with BP neural network.And the two methods have different recognition focuses.Finally,estimate and analyze the oil spill volume of emulsified oil on the sea surface.One method is based on statistical learning theory,using regression analysis methods to carry out specific numerical statistics and establish a corresponding value model.The other method is based on the idea of equivalence,adopting the method of equivalent emulsified spilled oil to oil film,and establishing equivalent models corresponding to water-in-oil and oil-in-water respectively.Finally,the research on quantitative estimation of emulsified oil spill is realized. |
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