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Characteristics of 13.9 GHz radar scattering from oil films on the sea surface
Author(s) -
Johnson J. W.,
Croswell W. F.
Publication year - 1982
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/rs017i003p00611
Subject(s) - scatterometer , backscatter (email) , remote sensing , scattering , nadir , radar , optics , microwave , polarimetry , materials science , geology , environmental science , physics , telecommunications , satellite , quantum mechanics , astronomy , computer science , wireless
An aircraft remote sensing project to study the response of a number of active and passive microwave and optical remote sensors to an oil‐covered sea surface was conducted by NASA Langley Research Center in 1979. Included was a 13.9‐GHz Doppler scatterometer, with a fan beam antenna and coherent detection, to measure radar backscatter as a function of incidence angle. The purpose of this paper is to present a comparison between the radar scattering signature of the clear surface and signatures of the surface while covered with a variety of crude oil films. The films were deposited on the surface from ships. Both in situ data and infrared aerial photography provided surface truth. Scattering changes were observed over a range of incidence angles from nadir to approximately 60°. Results show up to 14‐dB reduction in backscattered power between the clear surface and the films for horizontal polarization at an incidence angle of approximately 30°. In all cases, the greatest reduction in backscatter due to the oil was observed at approximately 30°, which suggests an optimum incidence angle for oil detection and mapping at 13.9 GHz (λ 0 = 2.16 cm). Maximum reduction in backscatter also appears to occur where the oil is the thickest.