Oil Slick Area Research Articles

Measurements of the Thickness and Area of Thick Oil Slicks Using Ultrasonic and Image Processing Methods

The in situ measurement of thick oil slick thickness (>0.5 mm) and area in real time in order to estimate the volume of an oil spill is very important for determining the oil spill response strategy and evaluating the oil spill disposal efficiency. In this article, a method is proposed to assess the volume of oil slicks by simultaneously measuring the thick oil slick thickness and area using ultrasonic inspection and image processing methods, respectively. A remotely operated vehicle (ROV), integrating two ultrasonic immersion transducers, was implemented as a platform to receive ultrasonic reflections from an oil slick. The oil slick thickness was determined by multiplying the speed of sound by the ultrasonic traveling time within the oil slick, which was calculated using the cross-correlation method. Images of the oil slick were captured by an optical camera using an airborne drone. The oil slick area was calculated by conducting image processing on images of the oil slick using the proposed image processing algorithms. Multiple measurements were performed to verify the proposed method in the laboratory experiments. The results show that the thickness, area and volume of a thick oil slick can be accurately measured with the proposed method. The method could potentially be used as an applicable tool for measuring the volume of an oil slick during an oil spill response.

An experimental study of oil slick contraction by chemical herders and fragmentation by obstacles

Chemical herders are a promising technique for treatment of oil spills in icy waters at high latitudes. However, obstacles on the water surface such as floating ice affects or interferes with all spill response countermeasures including chemical herder operations by fracturing the contracting oil slick and trapping small oil patches. Here we experimentally investigate the fluid dynamics of oil slick contraction and the interaction of the contracting oil slick with single obstacles of different shapes and sizes in a laboratory scale basin using Alaska North Slope crude oil and OP-40 herding agent. Oil slick area and thickness, oil-herder interface contraction speed, and the spatial distribution of the slick were optically measured over time, and particle image velocimetry (PIV) was used to measure the flow of the oil slick around the obstacles. For all obstacle sizes and shapes, an oil tail in the obstacle wake was generated as the oil-herder interface passed, which subsequently fractured by a capillary-type instability. Larger and less streamlined obstacles retained greater amounts of oil in these tails. In addition, a widely used theoretical thin film spreading model was successfully used to describe the spreading of the chemical herder against the oil slick at equilibrium. These results provide a foundation for future investigation of synergistic trapping of oil by multiple obstacles as would be seen in the field.

A novel method for determination of the oil slick area based on visible and thermal infrared image fusion

It is significant to prevent and supervise marine pollution through estimating the area of oil slick, when oil spill occurs. The existing determination method of the oil slick area has been developed based on visible image, which is influenced by illumination condition changes more easily. Since the thermal infrared image is almost not affected by illumination changes, it is introduced to determinate the area of oil slick. But it is hard to discriminate between oil slicks and look-alikes (the same thermal characteristics as oil film) without background and prior information. So, based on the visible and thermal infrared image fusion, a novel determination method of the oil slick area is proposed in this paper. The oil slick regions of interest (ROI) are extracted with help of the thermal infrared image processing. Then, based on Principal Component Analysis (PCA) fusion between visible and thermal infrared image, the background and priori information are obtained to discriminate the oil slick. The area of the real oil slick is calculated by the pixel area calculation method. The experimental results show that the proposed method can accurately determinate the oil slick area under different illumination, and the mean error is 2.78%. Moreover, compared with other method, the proposed method can achieve better results in both subjective evaluation and objective indicator. It seems to provide novel insights and supports for marine oil spill pollution control.

Forecasting System for Predicting the Dynamics of Oil Spill in a Tide-Dominated Estuary

ABSTRACT Crude oil is predicted to become one of the most detrimental sources of anthropogenic pollution to estuaries. A comprehensive survey of oil spill literature reveals that oil spill transport in estuaries presents a gap in academic knowledge and literature. To address this gap, we present the first detailed analysis of estuarine oil spill dynamics. We develop and analyse a range of simulations for the Humber Estuary, using TELEMAC3D; a coupled hydrodynamic and oil spill models. The river boundary of the Humber Estuary is forced by discharge data, while the offshore boundary is driven by tidal height data, including estuarine water temperature and salinity. The calibrated model shows good agreement with measured data during the validation process. Results show that: (a) the time of oil release within a tidal cycle significantly influences oil slick transport; and (b) the tidal range significantly influences oil slick impacted area and overall distance travelled, as oil slick released under spring tide is approximately double the oil slick size under neap tides and travels on average 71% farther. This study emphasises the need to: a) understand how the interaction of river discharge and tidal range influences oil slick transport; and (b) be aware of the time of release within a tidal cycle, to efficiently deal with oil spills. Findings should be useful for future operational oil spill response and could be equally applicable to other tide-dominated estuaries.

Oil Spill Detection from PlanetScope Satellite Image: Application to Oil Spill Accident near Ras Al Zour Area, Kuwait in August 2017

Park, S.-H.; Jung, H.-S.; Lee, M.-J.; Lee, W.-J., and Choi, M.-J., 2019. Oil spill detection from PlanetScope satellite image: Application to oil spill accident near Ras Al Zour area, Kuwait in August 2017. In: Jung, H.-S.; Lee, S.; Ryu, J.-H., and Cui, T. (eds.), Advances in Remote Sensing and Geoscience Information Systems of Coastal Environments. Journal of Coastal Research, Special Issue No. 90, pp. 251-260. Coconut Creek (Florida), ISSN 0749-0208.Oil spill accidents are major marine disasters that can destroy the ocean ecosystem. Satellite images are widely used to respond immediately to oil spill accidents. A miniaturized satellite equipped with an optical sensor has an advantage that the imaging period is very short because a large number of satellites can be operated. In this study, oil slick areas were detected by applying the artificial neural network (ANN) technique to the PlanetScope satellite optical image captured near Ras Al Zour, Kuwait on August 10, 2017. However, the image included sunglint effects owing to ocean waves and yellow dust areas, making it difficult to classify the oil slick area. In addition, the spilled oil had three different spectral information characteristics through interaction with the sea surface of the Persian Gulf. The image processing was divided into the pre-processing step and the oil slick classification step to detect the oil slick area and to mitigate these limitations. In the pre-processing step, a directional median filter was applied to reduce the sunglint effects caused by ocean waves, and the negative effects from the sea surface and dust were mitigated using the differences with the low-pass filtered image. In the oil slick detection step, three types of oil probability maps and one sea surface probability map were produced using the ANN technique. Subsequently, an oil slick classification map was produced by applying the maximum probability choosing method and dust area rejection. Through validation, the overall accuracy of the oil classification map was obtained to be 82.01 % and the kappa coefficient was 72.42 %. The proposed oil detection method can effectively detect different types of oil spill areas in optical images with sunglint and dust handicaps. Moreover, it has high potential to be used in the future because the revisit time of the satellite image used is shorter than that of other optical images.

Bird mortality from the Deepwater Horizon oil spill. I. Exposure probability in the offshore Gulf of Mexico

Following the 2010 Deepwater Horizon MC 252 blowout in the Gulf of Mexico, most surface oil remained more than 40 km offshore, precluding reliable estimation of offshore avian mortality based on shoreline counts. Using an exposure probability model as an alternative approach, we estimated that between 36 000 to 670 000 birds died in the offshore Gulf of Mexico as result of exposure to oil from the Deepwater Horizon, with the most likely number near 200 000. Our exposure probability model is a technique for estimating this offshore component of avian mortality as the product of the oil slick area, the density of the birds above the oil slick, and the proportionate mortality of birds that could be exposed to oil during an assumed exposure period. The duration of the exposure period is treated as an estimated parameter to account for oil slick movement, exposure of birds immigrating to the oil-contaminated area, and re-exposure of birds that survived prior vulnerability to exposure. Total avian mortality is determined as the sum of mortalities from each exposure period. Exposure probability may be the only method available to estimate bird mortality from large, remote oil spills in the open ocean where carcasses are unlikely to ever reach shore. In the case of the Deepwater Horizon, the uncertainty interval is quite large because several parameters could not be well estimated. Historically sparse survey coverage effectively led to an under-appreciation of the effects of this spill on marine birds.

Multimedia fate modeling of oil spills in ice-infested waters: An exploration of the feasibility of fugacity-based approach

The increasing demand for energy and the high probability of finding vast reserves have shifted offshore exploration and production activity into colder and harsher environments. Offshore activity increases risk of oil spills in these colder and harsher marine environments. The development of a spill contingency plan requires the prediction of fate and transport of oil. Oil spill trajectory and fate modeling in cold marine environments is an exceedingly complex problem, in which variability of physical environment and oil-ice interactions must be addressed. This paper explores the usefulness of the fugacity approach for spill fate and transport modeling in ice-infested waters through a simulation model that combines surface oil weathering algorithms with Level IV fugacity models. Four bulk compartments are used for modeling: air, ice cover, water and sediment. Weathering of surface oil on and under the ice cover is represented by a system of differential equations. Unsteady state mass balance equations are also developed for each of the four bulk phases. The outputs of the multimedia fate model are time-dependent profiles of oil slick area, fraction evaporated, water content in oil, viscosity, and concentration of oil in air, ice cover, water, and sediment. The application of the proposed model is illustrated through the simulation of a hypothetical oil spill in the Labrador Sea. The proposed model is simple but has the promise that it can be further developed to become directly useful to the simulation of spill behavior in ice-infested waters.

Comparison Of Semi-Automatic And Automatic Slick Detection Algorithms For Jiyeh Power Station Oil Spill, Lebanon

Abstract. After air strikes on July 14 and 15, 2006 the Jiyeh Power Station started leaking oil into the eastern Mediterranean Sea. The power station is located about 30 km south of Beirut and the slick covered about 170 km of coastline threatening the neighboring countries Turkey and Cyprus. Due to the ongoing conflict between Israel and Lebanon, cleaning efforts could not start immediately resulting in 12 000 to 15 000 tons of fuel oil leaking into the sea. In this paper we compare results from automatic and semi-automatic slick detection algorithms. The automatic detection method combines the probabilities calculated for each pixel from each image to obtain a joint probability, minimizing the adverse effects of atmosphere on oil spill detection. The method can readily utilize X-, C- and L-band data where available. Furthermore wind and wave speed observations can be used for a more accurate analysis. For this study, we utilize Envisat ASAR ScanSAR data. A probability map is generated based on the radar backscatter, effect of wind and dampening value. The semi-automatic algorithm is based on supervised classification. As a classifier, Artificial Neural Network Multilayer Perceptron (ANN MLP) classifier is used since it is more flexible and efficient than conventional maximum likelihood classifier for multisource and multi-temporal data. The learning algorithm for ANN MLP is chosen as the Levenberg-Marquardt (LM). Training and test data for supervised classification are composed from the textural information created from SAR images. This approach is semiautomatic because tuning the parameters of classifier and composing training data need a human interaction. We point out the similarities and differences between the two methods and their results as well as underlining their advantages and disadvantages. Due to the lack of ground truth data, we compare obtained results to each other, as well as other published oil slick area assessments.

Mapping sea surface oil slicks using RADARSAT-2 quad-polarization SAR image

[1] Polarimetric SAR decomposition parameters, average alpha angle () and entropy (H) are estimated for oil-slick contaminated sea surfaces and slick-free conditions using a RADARSAT-2 quad-polarization SAR image. The values of H and within oil slick areas are significantly higher than those of the ambient sea surface, indicating the dominance of Bragg scattering for the slick-free ocean and non-Bragg scattering for the oil-slick area. In land classification, the conformity coefficient (μ) is often used to discriminate surface scattering with double-bounce or volume scattering. Based on this rationale, we also develop a method using μ as a logical scalar descriptor to map oil slicks under low-to-moderate wind conditions. The proposed method is assessed using a RADARSAT-2 quad-polarization SAR image of oil slicks in the Gulf of Mexico. Analysis shows that when μ is positive the sea surface is slick-free, whereas μ is negative for oil-slick areas. This method provides a simple and effective mapping technique for oil slick detection.

Oil spill response planning with consideration of physicochemical evolution of the oil slick: A multiobjective optimization approach

This paper addresses the optimal planning of oil spill response operations under economic and responsive criteria, with consideration of oil weathering process. The economic criterion is measured by total cost, while the measure of responsiveness is the time span of the entire response operations. A bi-criterion, multiperiod mixed-integer linear programming (MILP) model is developed that simultaneously predicts the optimal time trajectories of oil volume and slick area, transportation profile, response resource utilization levels, cleanup schedule, and coastal protection plan. The MILP model integrates with the prediction of an oil weathering model that accounts for oil physicochemical properties, spilled amount, hydrodynamics, and weather conditions. The multi-objective optimization model is solved with the epsilon-constraint method and produces a Pareto optimal curve that reveals how the optimal total cost and response operations change under different specifications of responsiveness. We present two illustrative examples for oil spill incidents in the Gulf of Mexico and New England.

A numerical simulation of oil spill spreading on the coastal waters

Abstract The present study utilized the Lagrangian discrete parcel method to simulate the spreading of an oil spill on the coastal waters. The physical transport processes which include oil slick mechanical spreading, current advection, turbulent diffusion, evaporation, dissolution, and shoreline conditions are considered. Oil slick spreading area as a function of time for different conditions was also investigated. The simulation results are good in comparison with the field observation data. Numerical calculation results show that the whole oil slick splits into small slicks easier for a continuous spill than for an instantaneous spill. With a higher drift velocity, the whole oil slick splits into small slicks more easily.

SIR-B Experiments in Japan: Sensor Calibration and Oil Pollution Detection Over Ocean

Preliminary results of the SIR-B experiments conducted in Japan are reported mainly on the sensor calibration and the oil pollution experiments. No significant result was obtained for the rice crop experiment which was carried out at the same time, mainly due to the late flight of SIR-B. The sensor calibration experiment was eventually reduced to only the evaluation of the imaging characteristics of SIR-B. However, a reasonable relation between the image count and RCS is found, and the resolution analysis by using the corner reflector images gives satisfactory results. A possible cause leading to what are rather overestimates of the resolution is pointed out to be the background clutter. A simulated oil slick area over sea was clearly detected on the SIR-B image, although the incident angle was not so appropriate for the purpose. This result demonstrates the capability of a space-borne synthetic aperture radar for effective surveillance of oil spills over high seas.

THE SURVIVAL OF OIL SLICKS ON THE OCEAN AS A FUNCTION OF SEA STATE LIMIT1

ABSTRACT A research program is underway to obtain a better understanding of the interaction between spilled oil and sea state in order to predict the dispersion and ultimate physical fate of oil spilled in rough water. In pursuit of this goal, a theoretical study and two laboratory experimental studies are now complete. As a consequence, the lower limit of sea state at which globular dispersion of oil can be effected by ocean turbulence is calculable. The formation of oil globules by breaking waves, the penetration of globules into the water column, and the distribution of oil under breaking wave generated turbulence can also be modeled. A possible mechanism by which a coherent oil slick breaks up into small patches of oil (“slicklets”), caused by breaking waves, is described, and a simplified one-dimensional model of this effect is proposed. Results indicate that a 3 meter (significant wave height) sea will tend to initiate globular vertical dispersion of oil, although this process would take place over only about 13 percent of the oil slick's area. To effect a horizontal surface dispersion, breaking waves with a very long crest length are necessary, a type not ordinarily found in deep water.

The Continuous Spilling of Hot Oil on Ice

Abstract The continuous spilling of hot Norman Wells crude oil onto an ice surface was investigated with oil temperature, ice temperature and spilling rate as parameters. An equation for spreading of the oil was developed in whick the oil slick area, A, was proportional to t(1,2), where t is the elapsed time. Experimental data showed that A was prow portional to t0.8. Increases in both oil and ice temperatures were found to cause an increase in A, and temperature effects could be taken into account by relating kinematic viscosity to a function of the geometric mean of the ice and oil temperatures. Introduction ALTHOUGH the spreading of hot oil on ice is of interest from the point of view of oil spills in Arctic regions, no controlled quantitative study taking several variables into account has been published. In previous work, Chen et al.(1) studied the instantaneous release of oil under controlled isothermal conditions, and Glaeser(2) and McMinn(3) carried out non-isothermal field tests under a single experimental condition. The present work concerns the continuous spilling of hot crude oil on ice at ice temperatures down to −40 °C and oil temperatures up to 60 °C. Continuous spilling would occur in the event of a pipeline leak. The oil and ice temperatures chosen cover likely pipeline conditions during the Arctic winter. In common with the previous work(1), crude oil from commercial production at Norman Wells, Northwest Territories, Canada, was used. Mackay, Charles and Phillips'" have discussed other aspects of the physical behaviour of crude oil in Arctic environments, with particular reference to Norman Wells crude oil and the Mackenzie Valley of the Northwest Territories. Theoretical Background It has been recognized(1–3, 5–7) that the spreading of a liquid over a solid surface passes through three distinct regions: gravity-inertia, gravity-viscous and surface tension-viscous. However, in continuous spreading, the gravity-viscous region is of primary importance because surface-tension spreading is not likely to occur due to the continuous flow, and the gravity-inertia spreading, which occurs only in the area around the point of deposition, will not be observed. Using the same argument as that used by Chen et al.(1), the gravitational outward pressure force per unit volume is (Equation Available In Full Paper) In application of this model to the non-isothermal case of spreading of hot oil on ice, it should be noted that µ (or υ) must represent an effective viscosity, as there is a temperature gradient across the spreading oil film; any correlation of data in terms of equation (5) will therefore be in terms of such an effective viscosity. This notion is further reinforced by the observation that the spreading of hot oil on ice must of necessity involve flow of oil over a water film formed from the ice at the interface with the hot oil.

The multispectral concept as applied to marine oil spills

The detection and measurement of oil pollution in the marine environment are receiving augmented attention, as the incidence of oil spills increases with a corresponding demand for information to direct cleanup operations and assign legal responsibility. Owing to the complex behavior of oil on water, its susceptibility to transport and modification forces, and the physiochemical anomalies associated with its presence, both aerial and surface-based sensors are necessary components of a complete and effective monitoring system. Ultraviolet, thermal infrared, and microwave sensors exhibit capabilities potentially good for oil detection. Radar, in particular, possesses excellent promise for mapping an oil slick's area extent since it is operative day or night, under even adverse weather conditions. Since no present remote sensor system can as yet provide accurate information on the type or thickness of an oil slick, complementary data must be collected using surface-based mechanisms. Radiometric, meteorological, and oceanographic information are essential for a valid interpretation of remotely sensed data and a more complete analysis of the oil spill situation. Several potentially operational systems, coordinating remote sensing and surface data collection systems, for monitoring marine oil pollution are discussed, but more research is clearly needed to demonstrate the actual feasibility of any given method.