Modelling the Spectral Index to Detect a Baltic-Type Crude Oil Emulsion Dispersed in the Southern Baltic Sea

Zbigniew Otremba,Jacek Piskozub

doi:10.3390/rs13193927

Zbigniew Otremba, Jacek Piskozub

Open Access

https://doi.org/10.3390/rs13193927

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Abstract

Information was obtained on the possibility of detecting oil-in-water emulsions located under the sea based on the modelling of the directional distribution of the radiance field above the water surface. The optical sea model used applies to the southern Baltic Sea, while the oil emulsion model is based on the optical properties of crude oil extracted in this region of the sea. The analyses were carried out while taking into account eight wavelengths in the range 412–676 nm, assuming different thicknesses of the layer contaminated with oil. The most favourable combination of two wavelengths (555/412 nm) for the determination of an index related to the polluted sea area compared to the same index for oil-free water (difference index) was identified, the value of which is indicative of the presence of the oil emulsion in water. Changes in the difference index depending on the viewing direction are shown for almost the entire upper hemisphere (zenith angles from 0° to 80°). The observation directions for which the detection of emulsions should be the most effective are shown.

Highlights

Detecting oily substances in the marine environment is difficult when they are located below the sea surface
Information about their presence in the water column can only be transferred to the above-water detector in visible light, because all other types of electromagnetic waves are mostly absorbed by the water
Intensive studies have been carried out on the propagation of radio-real electromagnetic waves in water [1], it is not known how an oil-in-water emulsion may influence their propagation in the marine environment

Summary

Introduction

Detecting oily substances in the marine environment is difficult when they are located below the sea surface. Modelling the Spectral Index to Detect a Baltic-Type Crude Oil The oil droplets, together with the natural components of seawater, affect the directional and spectral distribution of light coming from the sea depths to the atmosphere and further to a potential detector detecting the presence of oil in the water column.

Results

Conclusion