Towards a framework for oil classification during oil spills in Arctic open water using microwave remote sensing

Arctic warming is extending the open water period, increasing interest in oil exploration, extraction, and transport through the extended shipping season, consequently raising the potential for an oil spill in the Arctic. Remote sensing for oil detection and characterization is at the forefront of oil spill response efforts. Here, we show that the density of an oil is related to its complex dielectric constant (CDC), a governing factor of microwave remote sensing. The relationship between oil density (ρ) and the real part of the oil CDC ( ε ′ ) as a function of composition and temperature was thoroughly investigated and a simple linear equation to describe the two variables was attained ( ε ′ = 2.0396 ρ + 0.4961 ). Based on this oil density-CDC relationship, a framework was built for radar technologies to classify spilled oil as light, medium, heavy, or extra-heavy using forward and inverse modelling of the Normalized Radar Cross-Section to better inform responders on how to approach the oil spill and what mitigation procedures are most appropriate. • Oil density and the real part of CDC have a tangible linear relationship. • The real part of CDC changes by a factor of two compared to oil density. • Radar can classify spilled oil based on the oil density-CDC relationship. • C-band radar is sensitive to oil type classification for open water and ice scenarios. • Radar sensitivity to oil type classification depends on incidence angle and frequency.