Retrieval of Oil–Water Mixture Ratio at Ocean Surface Using Compact Polarimetry Synthetic Aperture Radar

Li, Haiyan; Perrie, William; Wu, Jin

doi:10.3390/rs11070816

Cited by 13 publications

(13 citation statements)

References 54 publications

(173 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In order to extract the volumetric oil fraction, the system noise needs to be low in the two copolarization channels. The studies in [3], [49], [50] used low noise floor radars on airplanes to extract the oil fraction. Using spaceborne satellites with higher noise floor will present a challenge.…”

Section: Scattering Properties and Polarimetric Sar Featuresmentioning

confidence: 99%

The Impact of System Noise in Polarimetric SAR Imagery on Oil Spill Observations

Espeseth

Brekke

Jones

et al. 2020

IEEE Trans. Geosci. Remote Sensing

View full text Add to dashboard Cite

The effects of both system additive and multiplicative noise on X-, C-, and L-band Synthetic Aperture Radar (SAR) data covering oil slicks are examined. Prior studies have attempted to characterize such oil slicks, primarily through analysis of polarimetric SAR data. Here we factor in system noise that is added to the backscattered signal, introducing artifacts that can easily be confused with random and volume scattering. This confusion occurs when additive and/or multiplicative system noise dominates the measured backscattered signal. Polarimetric features used in this study are shown to be affected by both additive and multiplicative system noise, some more than others. This study highlights the importance of considering specifically multiplicative noise in the estimation of the signal-to-noise ratio (SNR). The SNR based on additive noise should at least be above 10dB. The SNR involving both additive and multiplicative noise should at least be above 0dB. The SNR from TerraSAR-X and Radarsat-2 is below 0dB for the majority of the oil slick pixels when considering both the additive and multiplicative noise, rendering these data unsuitable for any analysis of the scattering properties and characterization. These results are in contrast to the reduced impact of noise on oil slicks detected by the Lband UAVSAR system. In particular, we find there is no need to invoke exotic scattering mechanisms to explain characteristics of the data. We also recommend a noise subtraction for any polarimetric scattering analysis.

show abstract

Section: Scattering Properties and Polarimetric Sar Featuresmentioning

confidence: 99%

The Impact of System Noise in Polarimetric SAR Imagery on Oil Spill Observations

Espeseth

Brekke

Jones

et al. 2020

IEEE Trans. Geosci. Remote Sensing

View full text Add to dashboard Cite

show abstract

“…Another reason is that oil films with a smaller dielectric constant will also weaken the radar backscattering. In recent studies, the use of SAR images to extract the oil-water mixture ratio or the dielectric property of the oil-covered area has attracted more and more attention [40][41][42]. When the Bragg scattering dominates at a medium incident angle, the co-polarization ratio (HH/VV) is independent of the wave spectrum but depends on the dielectric properties of the sea surface.…”

Section: On Non-bragg Scattering From Oil-covered Sea Surfacementioning

confidence: 99%

Study on Non-Bragg Microwave Backscattering from Sea Surface Covered with and without Oil Film at Moderate Incidence Angles

et al. 2021

View full text Add to dashboard Cite

In the past decades, Bragg scattering has been considered to be an important scattering mechanism of microwave backscattering from sea surfaces. However, as reported in many recent literatures, non-Bragg scattering (which is often attributed to wave breaking) also makes a significant impact on radar scattering, especially for Horizontal–Horizontal (HH) polarized radar signals. To date, we know far less about non-Bragg scattering than Bragg scattering. Herein, this paper carries out an investigation on non-Bragg scattering and its effect on radar echoes at moderate incidence angles, both for oil-free and oil-covered sea surfaces. This paper firstly presents a systematic comparison of several sea spectra commonly used for the simulation of microwave scattering from sea surfaces. It is found that none of them perform well for the description of Bragg waves. Then, the “pure” Bragg wave spectra are inverted in the framework of the two-scale model (TSM) and geophysical model functions (GMFs). The normalized radar cross sections (NRCS) related to total scattering, non-Bragg scattering, and “pure” Bragg scattering in C, X, and Ku-bands are simulated under various conditions (i.e., incidence angles, wind speeds, and wind directions). Quantitative assessments of the relative contributions of non-Bragg scattering to total scattering are conducted. We also perform a survey on the non-Bragg scattering from the oil-covered sea surface. This article provides some new insights for a better understanding of the non-Bragg microwave scattering from rough sea surfaces at moderate incidence angles.

show abstract

“…al. [14] also attempted to determine the oil-water mixture ratio by employing the ratio of the diagonal elements of the covariance matrix for simulated Compact Polarimetry (CP) SAR from L-band UAVSAR data taken over the Deepwater Horizon (DWH) incident. While the results of this study were promising, the authors conclude that extensions of this method requires further work, as DWH represented an unprecedent oil spill event and the study was carried out using solely air bourn data.…”

Section: Retrieval Of Marine Surface Slick Dielectricmentioning

confidence: 99%

Retrieval of Marine Surface Slick Dielectric Properties From Radarsat-2 Data via a Polarimetric Two-Scale Model

Quigley

Brekke

Eltoft

2020

IEEE Trans. Geosci. Remote Sensing

View full text Add to dashboard Cite

We propose the use of a polarimetric two-scale surface scattering model to retrieve the dielectric parameters of oil slick from polarimetric synthetic aperture radar. The ocean surface is modeled as an ensemble of randomly orientated, slightly roughened, tilted facets for which the small perturbation model is assumed to be valid under the condition of no tilt. The orientation of the random facets causes a variation in the in-plane and out-of-plane tilt angles. As the original model utilizes both the co-polarization and cross-polarization channels to determine both the dielectric and roughness characteristics simultaneously from a series of look-up tables, the model is adapted from its original form in order to estimate the roughness characteristics of the scattering surface first, before the dielectric properties are inferred. The performance of the altered scattering model is then evaluated by applying it to multiple sets of quad-polarimetric data containing verified oil slicks, acquired from oil-on-water clean-up exercises in the North Sea. Histograms of retrieved values for the modulus of the dielectric constant indicate that the model is able to invert for values similar to the actual value of 2.3, the dielectric constant of pure crude oil at the lower limit, with successively higher values being found up to values of approximately 20 at the edges of the slicks. An error evaluation is also presented and demonstrates that sources of error are related to the alteration of the model to suit co-polarimetric data and the variance of the speckle which is related to the size of the averaging window. While the results are interesting, the approach is limited to the use of only the ratio of the co-polarimetric channels, from which two unknowns are estimated.

show abstract

Retrieval of Oil–Water Mixture Ratio at Ocean Surface Using Compact Polarimetry Synthetic Aperture Radar

Cited by 13 publications

References 54 publications

The Impact of System Noise in Polarimetric SAR Imagery on Oil Spill Observations

The Impact of System Noise in Polarimetric SAR Imagery on Oil Spill Observations

Study on Non-Bragg Microwave Backscattering from Sea Surface Covered with and without Oil Film at Moderate Incidence Angles

Retrieval of Marine Surface Slick Dielectric Properties From Radarsat-2 Data via a Polarimetric Two-Scale Model

Contact Info

Product

Resources

About