Oil spill modeling

Sensitivity maps can also be integrated with computerized oil spill models so that the impact of an oil spill on the environment can be projected. 

Spill models operate in a variety of modes. The most typical is the trajectory mode that predicts the trajectory and weathering of the oil. The stochastic mode uses available data to predict a variety of scenarios for the oil spill, which includes the direction, fate, and property changes in the oil slick. In another mode, often called the receptor mode, a site on the shore or water is chosen and the trajectory from the source of the oil is calculated. Increasingly, statistically generated estimates are added to oil spill models to compensate for the lack of accurate knowledge of winds and currents. 

Reed M, Johansen 0, Brandvik PJ, Daling P, Lewis A, Fiocco R, Mackay D, and Prentki R (1999) Oil spill modeling toward the close of the 20th century Overview of the state of art. Spill Science Technology Bulletin 5 3-16 Thomson TW, Liu WT, and Weissman DE (1983) Synthetic radar observation of ocean roughness from rolls in unstable marine boundary layer. Geophys Res Lett 10 1172-1175... 

Oil spill modeling needs to be performed before a spill occurs as part of a planning process for emergency response. This avoids the chicken-with-its-head-cut-off look that is often apparent in spill response teams. There will not be sufficient time following a spill to collect appropriate data and bring a model up to speed. Oil spill models are also valuable in a forensic investigation following an oil spill event. 

A. A. Allen and D. H. Dale. Dispersant mission planner A computerized model for the application of chemical dispersants on oil spills. In Proceedings Volume, volume 1, pages 393-414. 18th Environ Can Arctic Mar Oilspill Program Tech Seminar (Edmonton, Canada, 6/14-6/16), 1995. 

J. P. Fraser, S. A. Horn, L. J. Kazmierczak, M. L. Kinworthy, A. H. Lasday, and J. Lindstedt-Siva. Guidelines for use of dispersants on spilled oil— a model plan. In Proceedings Volume, pages 331-332. API et al Oil Spill (Prev, Behav, Contr, Cleanup) 20th Anniv Conf (San Antonio, TX, 2/13-2/16), 1989. 

Complete Mix Reactor - The complete mix reactor is also labeled a completely stirred tank reactor. It is a container that has an inhnite diffusion coefficient, such that any chemical that enters the reactor is immediately mixed in with the solvent. In Example 2.8, we used the complete mix reactor assumption to estimate the concentration of three atmospheric pollutants that resulted from an oil spill. We will use a complete mix reactor (in this chapter) to simulate the development of high salt content in dead-end lakes. A series of complete mix reactors may be placed in series to simulate the overall mixing of a one-dimensional system, such as a river. In fact, most computational transport models are a series of complete mix reactors. 

Mackay, D., Buist, I. Mascarenhas, R. Paterson, S. Oil Spill Process and Models, Report EE-8, Environment Canada Ottawa, 1980. 

The scientific advisor for an oil spill response unit assesses a spill and determines the appropriate clean-up methods. She or he acts as part of a team of advisors. Most advisors have an M.Sc. or Ph.D. in an area of expertise such as organic chemistry, physical chemistry, environmental chemistry, biology, oceanography, computer modelling, or chemical engineering. 

When oil spills on water, various transformation processes occur that are referred to as the behaviour of the oil. Two types of transformation processes are discussed in Chapter 4. The first is weathering, with emphasis on evaporation, the formation of water-in-oil emulsions, and natural dispersion, and the second is a group of processes related to the movement of oil in the environment. Spill modelling, wherein the behaviour and movement components of an oil spill are simulated using a computerized model, is also discussed. 

To protect sensitive resources and coastline, spill response personnel need to know the direction in which an oil spill is moving. To assist them with this, computerized mathematical models have been developed to predict the trajectory or pathway and fate of oil. Outputs of one such spill model are shown in Figure 10. 

Today s sophisticated spill models combine the latest information on oil fate and behaviour with computer technology to predict where the oil will go and what state... 

In addition to predicting the trajectory, these models can estimate the amount of evaporation, the possibility of emulsification, the amount of dissolution and the trajectory of the dissolved component, the amount and trajectory of the portion that is naturally dispersed, and the amount of oil deposited and remaining on shorelines. Accurate spill modelling is now a very important part of both contingency planning and actual spill response. 

For our improved statistical analysis we included the mean local wind-speed, as derived from interpolated values of the DWD model. As a first step we calculated the distribution of the detected oil spills with wind speed. As shown in the upper left panel of Figure 6 most oil spills were detected at mean (modelled) wind speeds between 3 m s"1 and 4 ms 1. The upper right panel of Figure 6 shows the wind speed distribution of the DWD model with a maximum between 5 m s"1 and 6 ms"1. The lower panel of Figure 6 shows the normalised oil spill visibility (NOSV) calculated as the (normalised) ratio of the two above. 

Fig. 6. upper left histogram of the distribution of detected oil pollution as function of wind speed upper right distribution of the DWD model winds lower left normalised oil spill visibility calculated as the ratio of the histograms for oil spills and model winds... 

The NOSV gives a better estimate of the detectability of marine oil pollution, independently of the local wind conditions of this particular study. These results show that higher wind speeds cause lower detectability of oil pollution, and the maximum (model) wind speed where oil spill detection in European coastal waters can be inferred. In particular, at wind speeds below 7 m s 1 oil spills are well detectable, whereas above 10 m s 1 wind speed the definite detection of marine oil pollution seems to be almost impossible. At wind speeds between 7 and 10 m s 1 the detectability of oil spills is rather low. These results can explain why less oil pollution was detected in the northern test areas during winter time. E.g., the mean wind speed in the central North Sea during winter time lies above 10 ms"1 (Figure 5), thus making it unlikely that every oil spill in that area was detectable by SAR sensors. 

Robbe N (2005) Airborne Oil Spill Remote Sensing Modelling, Analysis and Fusion of Multi-spectral Data. Institute of Experimental Physics, PhD Thesis, University of Hamburg, Germany... 

Refinement of methodologies for the prediction of oil spills movement, including oil dispersion model and ocean circulation models. This is a crucial aspect in case of accidents, but also in case of deliberate spilling close to the coastline. 

Reed M, Turner C, and Odulo A (1994) The role of wind and emulsification in modelling oil spill and drifter trajectories. Spill Science Technology Bulletin 1 143-157... 

Short and Heintz have developed a first-order loss-rate (FOLR) kinetic model of PAH weathering based on molecular size to evaluate environmental samples collected for the Exxon Valdez oil spill for the presence of spilled oil. They found that the predictability of the model is sufficiently robust that the initial PAH composition of oil can be inferred from analysis of a... 

Several items have been excluded in the B.C.L. model from the cost of corrosion. The loss of life and goodwill were not considered. Catastrophic and one-time costs were not included. Costs because of oil spill, advertising, and marketing costs related to corrosion resistance were not included. 

Figure 4. Event tree model for possible outcomes following the start event Oil spill from transformer . 

The model parameters chosen for the alternatives are stated in Table 5, and the expected values of annual oil spill for the chosen alternatives are illustrated in... 

The example of results achieved by the model is presented on Fig. 5. The long time distribution of accidental oil spills due to collisions on the southern Baltic Sea is divided into several classes. Such results (Gucma Przywarty 2007) could be very useful for decision makers to define high risk areas. 

MODELING OIL SPILLS ON RIVER SYSTEMS EVALUATION OF AQUEOUS CONCENTRATIONS... 

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