Phase Function of Seawater Polluted by Oil Emulsion

Abstract

Oil droplets suspended in the seawater will seriously affect the transmission characteristics of electromagnetic wave from ultraviolet and visible light to infrared. The scattering phase function can show the laser transmission characteristics in seawater polluted by oil. Water with oil emulsion has a phase function significantly different from that of natural ocean water. The accurate calculation of phase function can lay the foundation for laser propagation in the oil spill seawater, and is of great significance for protection of marine environment. This paper presents the modeling of phase function of seawater polluted by dispersed oil based on Mie scattering theory. Numerical calculation of scattering phase function of dispersed oil droplets in various times and at different wavelengths is conducted, and the numerical results of Henyey-Greenstein phase function and the modified Henyey-Greenstein phase function is given. The results show that the shapes of Mie scattering phase function of water with oil emulsion depend on wavelength and the oil emulsion ageing. The forward scattering attenuates with the time of oil emulsion ageing and the increase of incident wavelength, and the scattering gradually becomes homogeneously. Compared with Henyey-Greenstein the modified Henyey-Greenstein phase function can describe the scattering property of oil emulsion in the seawater better. But the fitting effects of both Henyey-Greenstein phase function and the modified Henyey-Greenstein phase function are undesirable for long time oil droplets, long wavelength and strong absorption ultraviolet light.