1、Designation: F2067 13Standard Practice forDevelopment and Use of Oil-Spill Trajectory Models1This standard is issued under the fixed designation F2067; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A nu
2、mber in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice describes the features and processes thatshould be included in an oil-spill trajectory and fate model.1.2 This practice app
3、lies only to oil-spill models and doesnot consider the broader need for models in other fields. Thispractice considers only computer-based models, and not physi-cal modeling of oil-spill processes.1.3 This practice is applicable to all types of oil in oceans,lakes, and rivers under a variety of envi
4、ronmental and geo-graphical conditions.1.4 This practice applies to two-dimensional models. Thereare three-dimensional models in the marketplace.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.2. Terminology2.1 Definitions:2
5、.1.1 trajectory modela computer-based program that pre-dicts the motion and fate of oil on water as a function of time.2.1.1.1 DiscussionInput parameters include oil properties,weather, and oceanographic information. There are four differ-ent modes: forecast, hindcast, stochastic, and receptor.2.1.2
6、 contingency planningplanning of several types toprepare for oil spills.2.1.2.1 DiscussionThis planning can include modelingsuch as described in this guide, to predict where oil spills mightgo and what the fate and properties of that oil would be.3. Significance and Use3.1 Trajectory models are used
7、 to predict the future move-ment and fate of oil (forecast mode) in contingency planning,in exercises and during real spill events. This information isused for planning purposes to position equipment and responsepersonnel in order to optimize a spill response. Oil-spilltrajectory models are used in
8、the development of scenarios fortraining and exercises. The use of models allows the scenariodesigner to develop incidents and situations in a realisticmanner.3.2 Oil-spill trajectory models can be used in a statisticalmanner (stochastic mode) to identify the areas that may beimpacted by oil spills.
9、3.3 In those cases where the degree of risk at variouslocations from an unknown source is needed, trajectory modelscan be used in an inverse mode to identify the sources of thepollution (hindcast mode).3.4 Models can also be used to examine habitats, shorelines,or areas to predict if they would be h
10、it with oil from a givensource (receptor mode).4. Modelling Methods4.1 Models simulate the movement of oil on water, calcu-lates the various weathering processes and considers theinteraction of the oil with the shoreline. The input data neededby the model includes area maps, oil properties, and spat
11、ial andtemporal vectors of wind and ocean currents. In some models,there are separate programs for advection and fate. In somecases, the fate models calculate weathering on the total mass ofthe oil rather than on individual particles. Some models includeresponse strategies (skimming, burning, disper
12、sing, and soforth) and the effect of these on the mass balance.4.2 The computer model calculates the surface fate of the oilusing physical and chemical properties of the oil and weath-ering algorithms.4.3 The output of a model is a map showing oil-slicklocations as a function of time, and graphs and
13、 tables of theweathering of the oil and mass balance.4.4 The output of the model is subject to uncertainties,primarily caused by uncertainties in the input data fromforecast winds and predicted ocean currents. The model shouldinclude an estimate of the magnitude of these uncertainties. Itshould be r
14、ecognized that models are only a tool and thusoutputs should always be confirmed by ground-truthing.5. Input Modelling Parameters5.1 In order to generate a georeferenced output, it isnecessary to have a suitable base map. This map should have1This practice is under the jurisdiction of ASTM Committee
15、 F20 on HazardousSubstances and Oil Spill Response and is the direct responsibility of SubcommitteeF20.16 on Surveillance and Tracking.Current edition approved April 1, 2013. Published April 2013. Originallyapproved in 2000. Last previous edition approved in 2007 as F2067 07. DOI:10.1520/F206713.Cop
16、yright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1a resolution in the order of 100 m near shore and 1 km in theopen ocean. The base-map data should be in a commonmapping format. The map should be vector-based in order thatthe output can be
17、 scaled to be consistent with the extent of thetrajectory. The data on the map should be organized in layers,with ocean current, wind fields, and trajectory informationavailable as separate layers. Other common layers are re-sources at risk, sensitive habitats, water intakes, socioeconomicparameters
18、, and so forth.5.2 The physical and chemical properties of the oil areneeded in order to calculate the weathering of the oil. This datashould be derived from readily available distillation datacurves and other standard oil-industry crude descriptors. Cata-logues are available that include parameters
19、 used in oil-spilltrajectory models. The need for the determination of model-specific parameters should be avoided where possible.5.3 The spatial and temporal distribution of wind fields isrequired to drive the advection terms of the model. These windfields should be input as a time series of vector
20、s, with separateinputs for each wind-data source. The modeling programshould have methods to interpolate the data from the individualwind observations. In some cases, weather data would beavailable as large scale synoptic charts. The computer programshould be able to translate these maps into the re
21、quired windfields.5.4 The ocean current regime can be divided into threecomponents: wind-driven currents, tidal currents, and residualcurrents.5.4.1 The vector sum of these three currents is the spatialand temporal driving force that moves the oil on the oceansurface. The total ocean current equatio
22、n must obey thecontinuity equation so that the model does not generateartificial sources and sinks. The wind-driven currents aredirectly mapped from the wind field, with a factor of about 3 to3.5 % commonly used to convert the wind vector into thecorresponding surface ocean-current vector.5.4.2 The
23、ocean-current vectors that are produced by tidalaction are strongly dependent on the bathymetry and shorelineshape of the area involved. Tidal currents follow the tidalperiod, with strong spatial changes depending on the tidalcycle. There are many schemes that have been derived tocompute such curren
24、ts. Hydrodynamics models are sometimesused to generate oceanographic data. Real time oceanographicdata from buoys provides both current and winds of highaccuracy.5.4.3 The residual currents are strongly spatially dependentbut remain constant in time over the duration of most spillmodel calculations.
25、 This may not be true for stochasticcalculations that have time periods of months to years.5.4.4 In estuaries, there are very complex currents, whichare difficult to predict using available models.5.4.5 The computation of ocean currents is complex andshould be supplemented by actual measurements usi
26、ng drifterbuoys and oceanographic current meters. In many situations,simple current measurement using floating objects can be usedand are better than no measurements.5.5 There are many limitations to the ability of models topredict oil movement and fate, and the output should beregarded as guidance
27、rather than an absolute prediction.6. Model Characteristics6.1 Most models divide the slick into a number of particles,each of which is advected and weathered separately. Theseparticles are treated as moving elements. The real slick iscontinuous and not quantized. If insufficient particles are usedb
28、y the model, then anomalous results are generated. The totalnumber of particles in the model should be greater than 100 atall times.6.2 The model should include the weathering of the oil withtime. Essential processes are:6.2.1 Evaporation,6.2.2 Emulsification,6.2.3 Dissolution,6.2.4 Natural dispersi
29、on, and6.2.5 Sinking.6.3 The stranding of oil on shorelines should be calculatedas a function of shoreline properties as well as metoceanconditions. The retention of oil by the shoreline should becharacteristic of the shoreline and derived from the shorelinelayer on the map.6.4 The model should have
30、 the capability of includingexternal observations, such as data from remote sensing, toadjust the output of the model to conform to the newinformation. The model should automatically adjust to reflectthe new observations.6.5 The model should calculate the confidence limits of theoutput.7. Model Outp
31、ut7.1 The model output should be presented on a map of thearea. This map should be derived from a Geographic Informa-tion System (GIS), with layers for the trajectory models, inputwind data, input ocean currents, and confidence levels of thepredictions. Weathering and mass balance should be present
32、asa time series graph and in tabular form.7.2 Estimates of uncertainties for both the movement andfate of the oil should be clearly indicated on the output.8. Keywords8.1 computer-based model; fate and weathering model; oilspill surveillance and tracking; oil spill trajectoryF2067 132ASTM Internatio
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