Study On The Scattering Field And Mueller Matrix Of Seawater And Sea Surface Oil Film

Oil spills at sea are the most common and serious form of water pollution,causing incalculable damage to the environment and economy,and threatening human safety,so detection and identification of oil spills at sea is necessary.Condensate,Yiyang oil and GII oil are fuel crude oils commonly used by industry and the scattering characteristics and Mueller matrices of these three oil films and seawater are investigated in this thesis,with the following work:1.Random rough sea surface was generated by linear filtering method,and the scattering of light waves on rough sea surface and oil film was analyzed based on Kirchhoff's approximation method,and the expression of spatial scattering field was obtained,the scattered light intensity distribution of s wave and p wave scattered by condensate oil,instrument lift oil,GII oil and seawater surface under different frictional wind speeds in the incident plane was numerically simulated.The results show that seawater and oil film have similar scattered light intensity distribution,both scatter the strongest near the reflection direction,s wave scattered light intensity is stronger than p wave,the peak scattered light intensity of oil film is greater than seawater,and the greater the difference in refractive index between oil film and seawater,the greater the difference in peak scattered light intensity,but with the increase of friction wind speed,the difference decreases,and it is difficult to distinguish oil film and seawater.2.The Mueller matrices of the sea surface and the oil film were numerically calculated for different friction wind speeds and the effects of friction wind speed,incidence angle,scattering angle and scattering azimuth angle on the Mueller matrices were analysed.The results show that the Mueller matrix components of the sea surface and oil film are symmetrically(or antisymmetrically)distributed when the incidence angle,scattering angle and scattering azimuth angle are varied,and with increasing scattering azimuth angle,the eight components of m₀₀?m₀₁?m₁₀?m₁₁?m₂₂?m₂₃?m₃₂?m₃₃ are symmetrical on the axis of 1800 scattering azimuth to the left and right,and the remaining eight components are symmetrical on the axis of 180° to the centre.The |m₀₁/m₀₀| and |m₁₀/m₀₀| of seawater have a maximum at an incidence angle of 53°(seawater Brewster angle)and the |m₀₁/m₀₀|and |m₁₀/m₀₀| of oil films have a maximum at an incidence angle of 56°(oil film Brewster angle)and are not affected by frictional wind speed;In the incident plane,the seawater|m₀₁/m₀₀| and |m₁₀/m₀₀| have the maximum value when the scattering angle is equal to the incident angle(55°),the |m₂₂/m₀₀| and |m₃₃/m₀₀| have the maximum value at 40°,the|m₀₁/m₀₀| and |m₁₀/m₀₀| of the oil film have the maximum value at 56.5°,and the|m₂₂/m₀₀| and |m₃₃/m₀₀| have the maximum value at 35°;while the oil film is not 0,these differences between seawater and oil film can distinguish seawater and oil film on the sea surface.The research results provide a theoretical basis for the identification of offshore oil slicks.