scholarly journals ON THE ESTIMATION OF POLARIMETRIC PARAMETERS FOR OIL SLICK FEATURE DETECTION FROM HYBRID POL AND DERIVED PSEUDO QUAD POL SAR DATA

2018 ◽  
Vol XLII-5 ◽  
pp. 629-635 ◽  
Author(s):  
S. Hari Priya ◽  
P. V. Jayasri ◽  
E. V. S Sita Kumari ◽  
A. V. V. Prasad
Keyword(s):  
Oil Spill ◽  
Feature Detection ◽  
Oil Spills ◽  
Single Channel ◽  
Marine Ecosystem ◽  
High Sensitivity ◽  
Oil Slick ◽  
Long Term Effect ◽  
Prime Concern ◽  
Spread Area

<p><strong>Abstract.</strong> Oil spills in oceans have a significant long term effect on the marine ecosystem and are of prime concern for maritime economy. In order to locate and estimate the oil spread area and for quantitative damage assessment, it is required to continually monitor the affected area on the sea and its surroundings and space based remote sensing makes this technically viable. Synthetic Aperture Radar SAR with its high sensitivity to target dielectric constant, look angle and polarization-dependent target backscatter has become a potential tool for oil-spill observation and maritime monitoring. From conventional single-channel SAR (single-pol, HH or VV) to multi-channel SAR – (Dual/Quad-polarization) and more recently compact polarimetric (Hybrid/Slant Linear) SAR systems have been widely used for oil-spill detection in the seas. Various polarimetric features have been proposed to classify oil spills using full, dual and compact polarimetric SAR. RISAT-1 is a C-band SAR with Circular Transmit and Linear Receive (CTLR) hybrid polarimetric imaging capability.This study is aimed at the polarimetric processing of RISAT-1 hybrid pol single look complex (SLC) data for derivation of the decisive polarimetric parameters which can be used to identify oil spills in oceans and their discrimination from look-alike signatures. In order to understand ocean–oil spill signatures from full-quad pol SAR, pseudo-quad pol covariance matrix is constructed from RISAT-1 hybrid pol using polarimetric scattering models .Then polarimetric processing is carried out over pseudo-quad pol data for oil slick detection. In-house developed software is used for carrying out the above oil-spill study.</p>

scholarly journals Dark spot detection for characterization of marine surface slicks using UAVSAR quad-pol data

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Vaishali Chaudhary ◽  
Shashi Kumar
Keyword(s):  
Oil Spills ◽  
Marine Ecosystem ◽  
Dark Spot ◽  
Accurate Estimation ◽  
Support Vector ◽  
Potential Hazard ◽  
Significant Drop ◽  
Oil Slick ◽  
Spot Detection ◽  
Marine Surface

AbstractOil spills are a potential hazard, causing the deaths of millions of aquatic animals and this leaves a calamitous effect on the marine ecosystem. This research focuses on evaluating the potential of polarimetric parameters in discriminating the oil slick from water and also possible thicker/thinner zones within the slick. For this purpose, L-band UAVSAR quad-pol data of the Gulf of Mexico region is exploited. A total number of 19 polarimetric parameters are examined to study their behavior and ability in distinguishing oil slick from water and its own less or more oil accumulated zones. The simulation of compact-pol data from UAVSAR quad-pol data is carried out which has shown good performance in detection and discrimination of oil slick from water. To know the extent of separation between oil and water classes, a statistical separability analysis is carried out. The outcomes of each polarimetric parameter from separability analysis are then quantified with the radial basis function (RBF) supervised Support Vector Machine classifier followed with an accurate estimation of the results. Moreover, a comparison of the achieved and estimated accuracy has shown a significant drop in accuracy values. It has been observed that the highest accuracy is given by LHV compact-pol decomposition and coherency matrix with a classification accuracy of ~ 94.09% and ~ 94.60%, respectively. The proposed methodology has performed well in discriminating the oil slick by utilizing UAVSAR dataset for both quad-pol and compact-pol simulation.

scholarly journals OILSPILL AND LOOK-ALIKE SPOTS FROM SAR IMAGERY USING OTSU METHOD AND ARTIFICIAL NEURAL NETWORK

2020 ◽  
Vol 4 (11) ◽  
pp. 1-10
Author(s):  
M. Sornam
Keyword(s):  
Image Segmentation ◽  
Oil Spill ◽  
Oil Spills ◽  
Marine Ecosystem ◽  
Dark Spot ◽  
Oil Spill Detection ◽  
Otsu Method ◽  
Artificial Neural ◽  
Propagation Network

Oil spill pollution plays a significant role in damaging marine ecosystem. Discharge of oil due to tanker accidents has the most dangerous effects on marine environment. The main waste source is the ship based operational discharges. Synthetic Aperture Radar (SAR) can be effectively used for the detection and classification of oil spills. Oil spills appear as dark spots in SAR images. One major advantage of SAR is that it can generate imagery under all weather conditions. However, similar dark spots may arise from a range of unrelated meteorological and oceanographic phenomena, resulting in misidentification. A major focus of research in this area is the development of algorithms to distinguish ‘oil spills’ from ‘look-alikes’. The features of detected dark spot are then extracted and classified to discriminate oil spills from look-alikes. This paper describes the development of a new approach to SAR oil spill detection using Segmentation method and Artificial Neural Networks (ANN). A SAR-based oil-spill detection process consists of three stages: image segmentation, feature extraction and object recognition (classification) of the segmented objects as oil spills or look-alikes. The image segmentation was performed with Otsu method. Classification has been done using Back Propagation Network and this network classifies objects into oil spills or look-alikes according to their feature parameters. Improved results have been achieved for the discrimination of oil spills and look-alikes.

scholarly journals Sacrificial amphiphiles: Eco-friendly chemical herders as oil spill mitigation chemicals

2015 ◽  
Vol 1 (5) ◽  
pp. e1400265 ◽  
Author(s):  
Deeksha Gupta ◽  
Bivas Sarker ◽  
Keith Thadikaran ◽  
Vijay John ◽  
Charles Maldarelli ◽  
...  
Keyword(s):  
Crude Oil ◽  
Oil Spill ◽  
Oil Spills ◽  
Cold Water ◽  
Marine Ecosystem ◽  
Hot Water ◽  
Sea Surface ◽  
Marine Biota ◽  
Polar Group ◽  
Branched Chain

Crude oil spills are a major threat to marine biota and the environment. When light crude oil spills on water, it forms a thin layer that is difficult to clean by any methods of oil spill response. Under these circumstances, a special type of amphiphile termed as “chemical herder” is sprayed onto the water surrounding the spilled oil. The amphiphile forms a monomolecular layer on the water surface, reducing the air–sea surface tension and causing the oil slick to retract into a thick mass that can be burnt in situ. The current best-known chemical herders are chemically stable and nonbiodegradable, and hence remain in the marine ecosystem for years. We architect an eco-friendly, sacrificial, and effective green herder derived from the plant-based small-molecule phytol, which is abundant in the marine environment, as an alternative to the current chemical herders. Phytol consists of a regularly branched chain of isoprene units that form the hydrophobe of the amphiphile; the chain is esterified to cationic groups to form the polar group. The ester linkage is proximal to an allyl bond in phytol, which facilitates the hydrolysis of the amphiphile after adsorption to the sea surface into the phytol hydrophobic tail, which along with the unhydrolyzed herder, remains on the surface to maintain herding action, and the cationic group, which dissolves into the water column. Eventual degradation of the phytol tail and dilution of the cation make these sacrificial amphiphiles eco-friendly. The herding behavior of phytol-based amphiphiles is evaluated as a function of time, temperature, and water salinity to examine their versatility under different conditions, ranging from ice-cold water to hot water. The green chemical herder retracted oil slicks by up to ~500, 700, and 2500% at 5°, 20°, and 35°C, respectively, during the first 10 min of the experiment, which is on a par with the current best chemical herders in practice.

ANALISA PENCEMARAN LAUT OLEH PTT EXPLORATION AND PRODUCTION (PTTEP) AUSTRALASIA TERHADAP LAUT TIMOR INDONESIA

2020 ◽  
Vol 4 (2) ◽  
pp. 127
Author(s):  
Paulin Yosephin Marini ◽  
Sherlly Monica Bonsapia ◽  
Johni R.V. Korwa
Keyword(s):  
Oil Spill ◽  
Oil And Gas ◽  
Oil Spills ◽  
Marine Ecosystem ◽  
Oil Field ◽  
Australian Government ◽  
Compensation Mechanisms ◽  
Exploration And Production ◽  
Data Collection Technique ◽  
The Impact

<p><em>This study aims to analyze a blowout from an oil and gas leak owned by PTT Exploration and Production (PTTEP) Australasia in the Montara oil field in the Indonesian Timor Sea, and how to resolve disputes between Australia and Indonesia. A qualitative approach was used in this study, whilst the data collection technique was through library research. The theory of state responsibility, the concept of human security, and the concept of international maritime law are used to analyze disputes between Indonesia and Australia. The study found that the Montara oil spill had not only damaged the marine ecosystem but also polluted Indonesian waters. It also found that although the Australian government had formed a special commission to resolve cases and even used dispersant, it had not satisfied all parties. Several points are summarized. First, the Montara oil spill in Australia is a transnational study because the impact has crossed national borders. Secondly, UNCLOS has a weakness in the settlement of the Montara case because the Convention only provides a description related to ‘Responsibility of Each Country’ and does not specifically arrange material compensation mechanisms to countries that cause sea pollution. Third, the Montara oil spill has caused huge losses for Indonesian seaweed farmers, especially 13 districts in NTT. The recommendations are that the Indonesian government along with the Montara Victim Peoples’ Advocacy Team should continue to follow up the case of oil spills from the Montara platform and continue to fight for compensation to the Australian government and the PTTEP as the responsible party.</em></p>

scholarly journals MODELING THE WIND INFLUENCE IN AN OIL SPILL ALONG THE SOUTHERN BRAZILIAN SHELF

2012 ◽  
Vol 11 (1-2) ◽  
pp. 100
Author(s):  
C. E. Stringari ◽  
W. C. Marques ◽  
L. F. Mello ◽  
R. T. Edit
Keyword(s):  
Oil Spill ◽  
Oil Spills ◽  
Marine Ecosystem ◽  
Computational Cost ◽  
Temperature Fields ◽  
Local Wind ◽  
Wind Influence ◽  
Oil Density ◽  
Environmental Agencies ◽  
Spilled Oil

Oil spills can generate different effects in different time scales on the marine ecosystem. The numerical modeling of this process is an important tool with low computational cost which provides a powerful appliance to environmental agencies regarding the risk management. In this way, the objective of this work is evaluate the local wind influence in a hypothetical oil spill along the Southern Brazilian shelf. The numerical simulation was carried using the ECOS model (Easy Coupling Oil System), an oil spill model developed at the Universidade Federal do Rio Grande – FURG, coupled with the tridimensional hydrodynamical model TELEMAC3D (EDF, France). The hydrodynamic model provides the velocities, salinity and temperature fields used by the oil spill model to evaluate the behavior and fate of the oil. The results suggest that the local wind influence are the main forcing driven the fate of the spilled oil. The direction and intensity of the currents are important controlling the behavior and the tridimensional transportation of the oil, on the other hand, the turbulent diffusion is important for the horizontal drift of the oil. The weathering results indicate 40% of evaporation and 80% of emulsification, and the combination of these processes leads an increasing of the oil density around 53.4 kg/m³ after 5 days of simulation.

Prediction of Oil Slick Motions in Narragansett Bay

1973 ◽  
Vol 1973 (1) ◽  
pp. 531-540 ◽  
Author(s):  
Joel Premack ◽  
George A. Brown
Keyword(s):  
Oil Spill ◽  
Oil Spills ◽  
Current Data ◽  
Narragansett Bay ◽  
Technical Literature ◽  
Arrival Times ◽  
Drift Motion ◽  
Oil Slick ◽  
Wind Actions ◽  
Current Characteristics

ABSTRACT In the development of meaningful oil spill contingency plans, it is of great value in establishing the response to a spill emergency to have predictions of oil slick motions once the spill occurs. In an attempt to evaluate some of the present technical literature on oil spill motion, a calculation was made for the oil spill motion which occurred in Narragansett Bay in September, 1960 when the tanker P.W. Thirtle ran aground and emitted about 24,000 barrels of Bunker C oil over a 12 hour period before successful abatement of the source was completed. The existing literature on oil slick spreading was reviewed and the work of Fay was chosen to represent the slick's spreading characteristics. The existing literature on oil slick drift was reviewed and the work of Teason, et. al, was used to establish the drift motion under the influence of current and wind actions. An available numerical hydrodynamic model of Narragansett Bay was used to calculate the current characteristics in the vicinity of the spills during the period of interest. Appropriate wind data were combined with the current data in order to obtain the important hydrodynamic and meteorological conditions. Since no comprehensive theory exists at the moment for oil slick spreading and drift, a simple model was taken in which the 24,000 barrels were emitted from the source in the form of 12 hourly discharges of 2000 barrels each. These individual spills were then handled on the basis of the available spreading theory and the drift motion calculated as described above. Although this is a crude approximation, it does give an estimate of the location and area magnitude of the spreading as a function of time after the spill. The predicted results were compared with documentation of this spill as presented in the Providence Journal. The overall slick motion as calculated by this procedure was in good agreement with arrival times of the spill in Newport Harbor and other places in Narragansett Bay and with the overall surface area involved in the spill. This example of the calculation of the oil slick motion in an estuary at least gives some confidence to oil spill contingency planners that numerical calculations can be made for use in planning response and abatement to oil spills.

scholarly journals Modeling of Accidental Oil Spills at Different Phases of LNG Terminal Construction

2021 ◽  
Vol 9 (4) ◽  
pp. 392
Author(s):  
Byoungjoon Na ◽  
Sangyoung Son ◽  
Jae-Cheon Choi
Keyword(s):  
Oil Spill ◽  
Oil Spills ◽  
Current Model ◽  
Contributing Factors ◽  
Loosely Coupled ◽  
Oil Slick ◽  
Advection Dispersion ◽  
Efdc Model ◽  
Spilled Oil ◽  
Environmental Fluid

Accidental oil spills not only deteriorate biodiversity but also cause immediate threats to coastal environments. This study quantitatively investigates the initial dispersion of spilled oil using the environmental fluid dynamics code (EFDC) model, loosely coupled with an endorsed oil spill model (MEDSLIK-II) accounting for time-dependent advection, diffusion, and physiochemical weathering of the surface oil slick. Focusing on local contributing factors (i.e., construction activities) to oil dispersion, the current model is applied to likely oil spills occurring at three different phases of the Songdo LNG terminal construction on a reclaimed site in South Korea. Applied phases pose detailed ship collision scenarios generated based on a proposed construction plan of the terminal. The effects of permeable revetments, required for reclamation, on the currents were also investigated and applied in subsequent oil spill modeling. For each scenario, the simulated results showed distinct patterns in the advection, dispersion, and transformation of the oil slick. Oil absorption into the coast, which causes immense damage to the coastal communities, is found to be highly dependent on the tidal currents, volume of oil spilled, and nearby construction activities.

scholarly journals DSS-OSM: An Integrated Decision Support System for Offshore Oil Spill Management

Water ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 20
Author(s):  
Pu Li ◽  
Bing Chen ◽  
Shichun Zou ◽  
Zhenhua Lu ◽  
Zekun Zhang
Keyword(s):  
Decision Support ◽  
Decision Support System ◽  
Oil Spill ◽  
Support System ◽  
Oil Spills ◽  
Marine Ecosystem ◽  
Social Economy ◽  
Effective Decision Support ◽  
Management Case Study ◽  
Offshore Oil

The marine ecosystem, human health and social economy are always severely impacted once an offshore oil spill event has occurred. Thus, the management of oil spills is of importance but is difficult due to constraints from a number of dynamic and interactive processes under uncertain conditions. An integrated decision support system is significantly helpful for offshore oil spill management, but it is yet to be developed. Therefore, this study aims at developing an integrated decision support system for supporting offshore oil spill management (DSS-OSM). The DSS-OSM was developed with the integration of a Monte Carlo simulation, artificial neural network and simulation-optimization coupling approach to provide timely and effective decision support to offshore oil spill vulnerability analysis, response technology screening and response devices/equipment allocation. In addition, the uncertainties and their interactions were also analyzed throughout the modeling of the DSS-OSM. Finally, an offshore oil spill management case study was conducted on the south coast of Newfoundland, Canada, demonstrating the feasibility of the developed DSS-OSM.

scholarly journals Numerical Modelling of Oil Spill Transport in Tide-Dominated Estuaries: A Case Study of Humber Estuary, UK

2021 ◽  
Vol 9 (9) ◽  
pp. 1034
Author(s):  
Chijioke D. Eke ◽  
Babatunde Anifowose ◽  
Marco J. Van De Wiel ◽  
Damian Lawler ◽  
Michiel A. F. Knaapen
Keyword(s):  
Oil Spill ◽  
River Discharge ◽  
Oil Spills ◽  
Model Performance ◽  
High Water ◽  
Tidal Range ◽  
Oil Slick ◽  
Tidal Cycles ◽  
Oil Spill Response ◽  
Humber Estuary

Oil spills in estuaries are less studied and less understood than their oceanic counterparts. To address this gap, we present a detailed analysis of estuarine oil spill transport. We develop and analyse a range of simulations for the Humber Estuary, using a coupled hydrodynamic and oil spill model. The models were driven by river discharge at the river boundaries and tidal height data at the offshore boundary. Satisfactory model performance was obtained for both model calibration and validation. Some novel findings were made: (a) there is a statistically significant (p < 0.05) difference in the influence of hydrodynamic conditions (tidal range, stage and river discharge) on oil slick transport; and (b) because of seasonal variation in river discharge, winter slicks released at high water did not exhibit any upstream displacement over repeated tidal cycles, while summer slicks travelled upstream into the estuary over repeated tidal cycles. The implications of these findings for operational oil spill response are: (i) the need to take cognisance of time of oil release within a tidal cycle; and (ii) the need to understand how the interaction of river discharge and tidal range influences oil slick dynamics, as this will aid responders in assessing the likely oil trajectories.

Life under an oil slick: response of a freshwater food web to simulated spills of diluted bitumen in field mesocosms

2020 ◽  
Vol 77 (5) ◽  
pp. 779-788 ◽  
Author(s):  
Jeffrey Cederwall ◽  
Tyler A. Black ◽  
Jules M. Blais ◽  
Mark L. Hanson ◽  
Bruce P. Hollebone ◽  
...  
Keyword(s):  
Oil Spill ◽  
Oil Spills ◽  
Ecological Impacts ◽  
Heavy Crude Oil ◽  
Oil Slick ◽  
Oil Transportation ◽  
Heavy Crude ◽  
Freshwater Environments ◽  
Freshwater Community ◽  
Planktonic Communities

Heavy crude oil transportation over land is increasing, yet the ecological impacts of spills, particularly of diluted bitumen, in freshwater environments remain poorly understood. We simulated spills of diluted bitumen in 1400 L land-based mesocosms containing water and sediments from a boreal, oligotrophic lake and monitored the response of natural planktonic communities over 11 days. Most species of phytoplankton (chrysophytes and dinoflagellates) and zooplankton (copepods and cladocerans) were sensitive to oil, exhibiting >70% overall abundance reductions in response to the spills. Declines in nano- and microphytoplankton were short-lived and began to recover after the oil sank, whereas picophytoplankton and zooplankton populations remained depressed at the end of the experiment. In contrast, oil spills stimulated bacteria known to degrade hydrocarbons, especially Alphaproteobacteria, whereas Gammaprotobacteria (a common marine oil spill bacterial class) increased less. This is the first experiment to examine the effects of diluted bitumen in a multitrophic freshwater community.

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