Estimation of emissivity and scattering coefficient of low saline water contaminated by diesel in Cj band (5.3 GHz) and Ku band (13.4 GHz)

Abstract

In case of low salinity or variable salinity, there is a very shallow radius of investigation. The dielectric constant of low saline water can be significantly modified by the presence of diesel. Techniques based on the propagation of electromagnetic waves may be used to detect contaminant and evaluate decontamination processes. Microwave remote sensing of diesel oil contaminated low saline water requires the study of electrical parameters of low saline water as well as diesel such as dielectric constant, emissivity and scattering coefficient along with their physical parameters like surface roughness, etc. The measurement of dielectric constant is very essential for estimating the emissivity and scattering coefficient. The measurement of dielectric constant of low saline water in combination with diesel has been carried out using waveguide cell with shift in minima method in 5.3 and 13.4 GHz. Tests are conducted with samples of different salinity of water with various amount of diesel oil. The amount of salinity is 5, 10 and 15 kppm and the amount of diesel contamination is from 40 to 280 percent with the interval of 80 percent for Cj band (5.3 GHz) and 40 to 160 percent with the interval of 40 percent for Ku band (13.4 GHz). The estimation of emissivity and scattering coefficient have been done for incident angles varying from 10 to 80 degree with the interval of 5 degree for both horizontal and vertical polarization. The value of Brewster angle has been calculated and the values of emissivity and scattering coefficient for three look angles (45, 50 and 55) degree is presented which are useful for designing space borne active and passive sensors. Furthermore, this database is useful for detecting oil spills in low saline water.