Title
Simulation of an oil film at the sea surface and its radiometric properties in the SWIR
Author
Schwenger, F.
van Eijk, A.M.J.
Contributor
Schleijpen, R. (editor)
Stein, K.U. (editor)
Publication year
2017
Abstract
The knowledge of the optical contrast of an oil layer on the sea under various surface roughness conditions is of great interest for oil slick monitoring techniques. This paper presents a 3D simulation of a dynamic sea surface contaminated by a floating oil film. The simulation considers the damping influence of oil on the ocean waves and its physical properties. It calculates the radiance contrast of the sea surface polluted by the oil film in relation to a clean sea surface for the SWIR spectral band. Our computer simulation combines the 3D simulation of a maritime scene (open clear sea/clear sky) with an oil film at the sea surface. The basic geometry of a clean sea surface is modeled by a composition of smooth wind driven gravity waves. Oil on the sea surface attenuates the capillary and short gravity waves modulating the wave power density spectrum of these waves. The radiance of the maritime scene is calculated in the SWIR spectral band with the emitted sea surface radiance and the specularly reflected sky radiance as components. Wave hiding and shadowing, especially occurring at low viewing angles, are considered. The specular reflection of the sky radiance at the clean sea surface is modeled by an analytical statistical bidirectional reflectance distribution function (BRDF) of the sea surface. For oil at the sea surface, a specific BRDF is used influenced by the reduced surface roughness, i.e., the modulated wave density spectrum. The radiance contrast of an oil film in relation to the clean sea surface is calculated for different viewing angles, wind speeds, and oil types characterized by their specific physical properties. © 2017 SPIE. The Society of Photo-Optical Instrumentation Engineers (SPIE)
Subject
2015 Observation, Weapon & Protection Systems
ED - Electronic Defence
TS - Technical Sciences
SWIR
Distribution functions
Gravity waves
Lubricating oils
Physical properties
Reflection
Surface roughness
Water waves
Wave power
BRDF
Oil films
Sea surfaces
Simulation
SWIR
Surface waters
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TNO identifier
782881
Publisher
SPIE
ISBN
9781510613287
ISSN
0277-786X
Source
Target and Background Signatures III 2017. 11 September 2017 through 12 September 2017, 10432
Series
Proceedings of SPIE - The International Society for Optical Engineering
Article number
104320D
Document type
conference paper