• Analysis of evolving oil spills in full-polarimetric and hybrid-polarity SAR 

      Espeseth, Martine Mostervik; Skrunes, Stine; Jones, Cathleen Elaine; Brekke, Camilla; Holt, Benjamin; Doulgeris, Anthony Paul (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-04-25)
      Oil spill detection using a time series of images acquired off Norway in June 2015 with the uninhabited aerial vehicle synthetic aperture radar is examined. The relative performance of a set of features derived from quad-polarization versus hybrid-polarity (HP) modes in detection of various types of slicks as they evolve on a high wind driven sea surface is evaluated. It is shown that the HP mode ...
    • Assessment of the RISAT-1 FRS-2 Mode for Oil Spill Observation 

      Skrunes, Stine; Brekke, Camilla; Espeseth, Martine M. (Peer reviewed; Chapter, 2017-12-04)
      Synthetic aperture radar data acquired by the Radar Imaging Satellite (RISAT-1) over experimental oil spills is here investigated. One quad-polarization scene in the Fine Resolution Alternate Polarization Stripmap (FRS-2) mode is analyzed to evaluate the potential of using this mode for oil spill observation.<br> Oil slicks of varying type and age are clearly detected in the HH and VV channels, with ...
    • Characterization and discrimination of evolving mineral and plant oil slicks based on L-band synthetic aperture radar (SAR) 

      Jones, Cathleen; Espeseth, Martine Mostervik; Holt, Benjamin; Brekke, Camilla; Skrunes, Stine (Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-10-18)
      Evolution of the damping ratio for Bragg wavenumbers in the range 32-43 rad/m is evaluated for oil slicks of different composition released in the open ocean and allowed to develop naturally. The study uses quad-polarimetric L-band airborne synthetic aperture radar data acquired over three mineral oil emulsion releases of different, known oil-to-water ratio, and a near-coincident release of 2-ethylhexyl ...
    • Characterization of Low Backscatter Regions in the Marine Environment by Multipolarization C- and X-band Synthetic Aperture Radar Data 

      Skrunes, Stine (Doctoral thesis; Doktorgradsavhandling, 2014-10-10)
      The focus of this thesis is the application of multipolarization SAR data for characterization of marine oil spills and other low backscatter ocean phenomena. A variety of SAR descriptors are investigated for the purpose of discriminating between oil spills and look-alikes. The effects of various parameters on the imaging, including sensor frequency, imaging geometry and oil properties, are addressed. ...
    • Classification of low backscatter ocean regions using log-cumulants 

      Skrunes, Stine; Brekke, Camilla (Conference object; Konferansebidrag, 2015-01)
      In a synthetic aperture radar image, low backscatter regions of various origin can be observed in ocean areas. Operational oil spill detection services work to discriminate anthropogenic oil spills from natural phenomena such as seeps, low wind fields, thin ice and biogenic slicks. In this paper, we investigate the potential of using matrix log-cumulants for this purpose.
    • Cross-Correlation Between Polarization Channels in SAR Imagery Over Oceanographic Features 

      Brekke, Camilla; Jones, Cathleen; Skrunes, Stine; Holt, Benjamin; Espeseth, Martine; Eltoft, Torbjørn (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-11)
      This letter discusses cross-correlation features de- rived from near-coincident RADARSAT-2 quad-polarimetric and RISAT-1 hybrid-polarity (HP) measurements collected during the NOrwegian Radar oil Spill Experiment in 2015 (NORSE2015). We show that the imaginary part of the cross-correlation between RH and RV is an HP parallel to the real part of the cross-correlation between HH and VV earlier ...
    • Effect of Wind Direction and Incidence Angle on Polarimetric SAR Observations of Slicked and Unslicked Sea Surfaces 

      Skrunes, Stine; Brekke, Camilla; Jones, Cathleen Elaine; Espeseth, Martine; Holt, Benjamin (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-12)
      The objective of this paper is to investigate the dependency of oil spill observations in polarimetric SAR data on imaging geometry, i.e., on incidence angle and look direction relative to the wind. The study is based on quad-polarization data acquired by the Uninhabited Aerial Vehicle Synthetic Aperture Radar over experimental oil slicks under relatively high winds of 10–12 m/s over an 8-hour period. ...
    • The Impact of Additive Noise on Polarimetric RADARSAT-2 Data Covering Oil Slicks 

      Espeseth, Martine; Skrunes, Stine; Brekke, Camilla; Johansson, Malin (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-14)
      We attempt to understand how a set of well known polari-metric Synthetic Aperture Radar (SAR) features are impacted by the additive system noise for mineral oil and produced water slicks. For this, we use quad-polarimetric SAR scenes from Radarsat-2. Oil slicks at sea can be detected using SAR instruments, and the dual- (HH-VV) and quad-polarimetric modes can provide additional information about the ...
    • Interpreting sea surface slicks on the basis of the normalized radar cross-section model using RADARSAT-2 copolarization dual-channel SAR images 

      Dmitry V., Ivonin; Skrunes, Stine; Brekke, Camilla; Ivanov, A. Yu. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-03-24)
      A simple automatic multipolarization technique for discrimination of main types of thin oil films (of thickness less than the radio wave skin depth) from natural ones is proposed. It is based on a new multipolarization parameter related to the ratio between the damping in the slick of specially normalized resonant and nonresonant signals calculated using the normalized radar cross-section model ...
    • Marine Target Characteristics in Satellite SAR Imagery 

      Skrunes, Stine (Master thesis; Mastergradsoppgave, 2011-02)
      In this thesis, marine targets in Synthetic Aperture Radar (SAR) imagery are studied. The appearance of different marine targets in different polarization channels, their scattering behaviour, and their contrast measures and geometric properties are investigated. RADARSAT-2 data containing ships, oil rigs and icebergs in ocean and/or sea ice background are evaluated. To be able to detect a target ...
    • Mineral Oil Slicks Identification Using Dual Co-polarized Radarsat-2 and TerraSAR-X SAR Imagery 

      Ivonin, Dmitry; Brekke, Camilla; Skrunes, Stine; Ivanov, Andrei; Kozhelupova, Nataliya (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-25)
      This study is devoted to a generalization of C-band Radarsat-2 and X-band TerraSAR-X synthetic aperture radar (SAR) data in the form of a diagram serving to easily identify mineral oil slicks (crude oil and emulsions) and separate them from the other oil slicks. The diagram is based on the multi-polarization parameter called Resonant to Non-resonant signal Damping (RND) introduced by Ivonin et al. ...
    • Multi-mission remote sensing of low concentration produced water slicks 

      Johansson, Malin; Skrunes, Stine; Brekke, Camilla; Isaksen, Hugo (Journal article; Tidsskriftartikkel, 2021-04)
      Produced water is legally released from oil platforms and often detected by oil spill detection services despite their low oil concentrations. Using fully-polarimetric RADARSAT-2 and dual-polarimetric Sentinel-1 data we investigate their synthetic aperture radar (SAR) characteristics. Detectability ranges within the SAR and optical Sentinel-2 and PlanetScope images are assessed and compared to in-situ ...
    • A Multisensor Comparison of Experimental Oil Spills in Polarimetric SAR for High Wind Conditions 

      Skrunes, Stine; Brekke, Camilla; Jones, Cathleen Elaine; Holt, Benjamin (Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-06-23)
      In this paper, we present the experimental setup and data collection during the Norwegian Radar oil Spill Experiment 2015, followed by a comparison of a subset of the multisensory synthetic aperture radar (SAR) imagery collected during the experiment. Multipolarization SAR data acquired by Radarsat-2, TerraSAR-X, and the uninhabited aerial vehicle synthetic aperture radar (UAVSAR) less than 6 min ...
    • Observing Oil Releases from Platforms Using Synthetic Aperture Radar 

      Skrunes, Stine; Johansson, Malin; Brekke, Camilla (Conference object; Konferansebidrag, 2018)
      Synthetic aperture radar (SAR) is used for operational surveillance of ocean areas and oil spill detection. Oil spills are frequently detected around oil platforms due to the releases of so-called produced water (PW), which is water containing low concentrations of oil that can form surface slicks similar to other oil spills. PW releases are legal within given limits. Understanding the signatures ...
    • Ocean Applications 

      Migliaccio, M.; Nunziata, F.; Marino, A.D.; Brekke, Camilla; Skrunes, Stine (Chapter; Bokkapittel, 2021-05-11)
      In this chapter, the most promising techniques to observe oil slicks and to detect metallic targets at sea using polarimetric synthetic aperture radar (SAR) data are reviewed and critically analysed. The detection of oil slicks in SAR data is made difficult not only by the presence of speckle but also by the presence of, e.g. biogenic films, low-wind areas, rain cells, currents, etc., which increase ...
    • Oil spill characterization in the hybrid-polarity SAR domain using log-cumulants 

      Espeseth, Martine; Skrunes, Stine; Brekke, Camilla; Salberg, Arnt Børre; Jones, Cathleen; Holt, Benjamin (Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-10-18)
      Log-cumulants have proven to be an interesting tool for evaluating the statistical properties of potential oil spills in polarimetric Synthetic Aperture Radar (SAR) data within the common horizontal (H) and vertical (V) polarization basis. The use of first, second, and third order sample log-cumulants has shown potential for evaluating the texture and the statistical distributions, as well as ...
    • Oil Spill Dispersion in Full-polarimetric and Hybrid-polarity SAR 

      Brekke, Camilla; Skrunes, Stine; Espeseth, Martine (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-04)
      We show that indications of spatial dispersion effects on mineral oil slicks are observed by space-borne multipolarization synthetic aperture radar. This is readily perceived by eye when correlating multipolarization synthetic aperture radar observables with the ship track of the dispersion vessel. We investigate real full-polarimetric (linear transmit/linear receive) as well as simulated and real ...
    • Oil-Spill-Response-Oriented Information Products Derived From a Rapid-Repeat Time Series of SAR Images 

      Espeseth, Martine; Jones, Cathleen; Benjamin, Holt; Brekke, Camilla; Skrunes, Stine (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-19)
      New quantitative and semiautomated methods for analyzing oil slick evolution using a time series of L-band synthetic aperture radar (SAR) images with short repeat time are developed and explored. In this study, two methods that are complementary in terms of identifying temporal changes within an oil slick are presented. The two methods reflect two ways of evaluating the oil slicks. The first method ...
    • Separation and characterisation of mineral oil slicks and newly formed sea ice in L-band synthetic aperture radar 

      Johansson, Malin; Espeseth, Martine; Brekke, Camilla; Skrunes, Stine (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-14)
      Maritime activities in the Arctic Ocean is increasing and consequently the risk for an oil spill there is rising. Synthetic Aperture Radar (SAR) is used operationally to detect and monitor oil slicks and for sea ice monitoring and observations. Leads are often used for ship routing and within the leads newly formed sea ice is often present. Separation between the low backscatter areas that constitutes ...
    • Synthetic Aperture Radar Remote Sensing of Operational Platform Produced Water Releases 

      Skrunes, Stine; Johansson, Malin; Brekke, Camilla (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-12-03)
      Oil spill detection services based on satellite synthetic aperture radar (SAR) frequently detect oil slicks close to platforms due to legal releases of produced water. Separating these slicks from larger releases, e.g., due to accidental leakage is challenging. The aim of this work is to investigate the SAR characteristics of produced water, including the typical appearance in HH/VV data, possible ...