1、Designation: F 2327 08Standard Guide forSelection of Airborne Remote Sensing Systems forDetection and Monitoring of Oil on Water1This standard is issued under the fixed designation F 2327; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revi
2、sion, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide provides information and criteria for selec-tion of remote sensing systems for the detect
3、ion and monitor-ing of oil on water.1.2 This guide applies to the remote sensing of oil-on-waterinvolving a variety of sensing devices used alone or incombination. The sensors may be mounted in helicopters,fixed-wing aircraft, or lighter-than-air platforms. Excluded aresituations where the aircraft
4、is used solely as a telemetry orvisual observation platform and exo-atmosphere or satellitesystems.1.3 The context of sensor use is addressed to the extent ithas a bearing on their selection and utility for certain missionsor objectives.1.4 This guide is generally applicable for all types of crudeoi
5、ls and most petroleum products, under a variety of marine orfresh water situations.1.5 Many sensors exhibit limitations with respect to dis-criminating the target substances under certain states of weath-ering, lighting, wind and sea, or in certain settings.1.6 This guide gives information for evalu
6、ating the capabil-ity of a remote surveillance technology to locate, determine theareal extent, as well as measure or approximate certain othercharacteristics of oil spilled upon water.1.7 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in this
7、standard.1.8 Remote sensing of oil-on-water involves a number ofsafety issues associated with the modification of aircraft andtheir operation, particularly at low altitudes. Also, in someinstances, hazardous materials or conditions (for example,certain gases, high voltages, etc.) can be involved. Th
8、isstandard does not purport to address all of the safety concerns,if any, associated with its use. It is the responsibility of the userof this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory require-ments prior to use.2. Significance and Use
9、2.1 The contributions that an effective remote sensing sys-tem can make are:2.1.1 Provide a strategic picture of the overall spill,2.1.2 Assist in detection of slicks when they are not visibleby persons operating at, or near, the waters surface or at night,2.1.3 Provide location of slicks containing
10、 the most oil,2.1.4 Provide input for the operational deployment of equip-ment,2.1.5 Extend the hours of clean-up operations to includedarkness and poor visibility,2.1.6 Identify oceanographic and geographic features to-ward which the oil may migrate,2.1.7 Locate unreported oil-on-water,2.1.8 Collec
11、t evidence linking oil-on-water to its source,2.1.9 Help reduce the time and effort for long range plan-ning,2.1.10 A log, or time history, of the spill can be compiledfrom successive data runs, and2.1.11 Asource of initial input for predictive models and for“truthing” or updating them over time.3.
12、Remote Sensing Equipment Capabilities andLimitations3.1 The capability of remote sensing equipment is, in largemeasure, determined by the physical and chemical propertiesof the atmosphere, the water, and the target oil. There may bevariations in the degree of sophistication, sensitivity, andspatial
13、resolution of sensors using the same portion of theelectromagnetic spectrum and detector technology. Sensorswithin a given class tend to have the same general capabilitiesand typically suffer from the same limitations.3.2 Combinations of sensors offer broader spectral coveragewhich, in turn, permit
14、better probability of detection, betterdiscrimination, and effective operation over a broader range ofweather and lighting conditions. Certain combinations, orsensor suites, are well documented, and their use is particularlysuited to oil spill response missions.3.3 The performance of virtually all s
15、ensors can be en-hanced by a variety of real-, near real-time or post processingtechniques applied to the acquired data or imagery. Further-more, image or data fusion can greatly enhance the utility of1This guide is under the jurisdiction of ASTM Committee F20 on HazardousSubstances and Oil Spill Re
16、sponse and is the direct responsibility of SubcommitteeF20.16 on Surveillance and Tracking.Current edition approved Sept. 15, 2008. Published September 2008. Originallyapproved in 2003. Last previous edition approved in 2003 as F 2327 03.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C
17、700, West Conshohocken, PA 19428-2959, United States.the remote sensing output or product. Similarly, there exists avariety of technological considerations and organizationalramifications that relate to the delivery of the remote sensinginformation to the user.3.4 Certain parameters need to be ident
18、ified and quantifiedto provide an oil spill response decision-maker with all of theinformation needed to best respond to a spill. These are:3.4.1 Locationof the approximate center and edges of thespill,3.4.2 Geometrysource or origin, total area, orientationand lengths of major and minor axes, fragme
19、ntation, anddistribution,3.4.3 Physical conditionsoil appearance, entrained debris,3.4.4 Environmental conditionswave height and direc-tion; water temperature; position of oceanic fronts, conver-gence and divergence zones,3.4.5 Proximity of threatened resources, and3.4.6 Location of response equipme
20、nt.3.5 Remote sensing can contribute to all of the above dataneeds. Depending on the spill situation and the employment ofremote sensing, some of this information may already beavailable, or can be determined more cost effectively by othermeans. For example, in a response mode, or tactical employ-me
21、nt of remote sensing, it is likely that the source, generallocation and type of oil have been reported well in advance ofthe launch of the remote sensing platform. In a regulatory orpatrol context, this information may not be available. The spillsituation influences the priorities among the elements
22、 ofinformation and, thereby, influences the selection priorities forsensors.3.6 A responder may require the data on an oil spill, 24hours per day, independent of the prevailing weather.3.7 Information from remote sensing is required in a timelymanner. Strategic or enforcement information, such as th
23、eoverall extent and location of a spill, should be availablepreferably within two to four hours from information gatheringto presentation.3.8 Tactical information, such as steering information forresponse vessels, should be available in as little as five minutesfrom detection to communication. The a
24、cceptable data deliverytime is a function of the dynamics of the slick, proximity tocritical areas, and the availability of clean-up resources.3.9 No sensor is currently available to give information onoil thickness. An IR camera may provide an indication that aslick is relatively thin or thick.3.10
25、 Table 1 lists sensors based upon their mode of opera-tion. Summary information on their advantages and disadvan-tages is presented.3.11 Table 2 presents a summary of key attributes whichgenerally influence the selection of remote sensing instrumen-tation.3.12 Table 3 addresses the mission specific
26、aspects of sensorselection.4. Summary4.1 The information presented in this guide should beconsidered a starting point for sensor selection. In addition tothe context of use and the attributes of the various types ofsensors, the system planner will have to give due considerationto the capabilities of
27、 the aircraft and the information needs ofthe users before finalizing the system design. Both sensortechnology, and image and data analysis capabilities areevolving rapidly. Most equipment is not commercially-available and requires assembly and in some cases requiresdevelopment. Up to two years lead
28、 time may be required forsome equipment.F2327082TABLE 1 Sensor CharacteristicsSensor/ Band Principal of Operation Positive Features LimitationsVisual Operate in, and near, the (human) visible spec-trum (400 to 750 nm). Using photographic films,scanners with one or more narrow band detectorsor charge
29、 coupled devices (CCD) to capture animage.Equipment is widely available, generallyinexpensive, light and easily accommodatedon most any aerial platform. Imagery is in every-day use and the layman can easily relate to itscontent. This characteristic makes the imageryan excellent base for recording an
30、d presentingother data.Oil is generally perceptible over the entire visiblespectrum, but not uniquely so. As such, instancesof not being able to discriminate the oil from itsbackground, or differentiate it from othersubstances or phenomena in or on the waterssurface, lead to frequent non-detects and
31、 falsepositives.Night vision cameras may extend the operationalwindow, but visual technologies are limited byavailable light.Infrared While the infrared (IR) spectrum ranges from 750nm to 1 mm, the bulk of the available remotesensing systems operate in the thermal or mid-IR,3 m (3000 nm) to 30 m (30
32、 000 nm). Withinthis range there are two predominant sub-groupsoperating at 3 to 5 m and 8 to 12 or 14 m.The latter range offers the most useful data foroil spills.Fresh oil shows a contrast to openwater in the thermal infrared. This characteristicis not unique to hydrocarbons. Slicks thickerthan ab
33、out 20 to 70 mAcan be seen.Newer IR cameras have excellent thermaldiscrimination, fairly good resolution, are light-weight, have modest power demands, andtypically have both digital and video outputs.Small patches, thin, or significantly weathered oilmay not be detectible. Other heterogeneities such
34、as high seaweed or debris content, oil in or on ice,oil on beaches, etc. may render the oilundetectable in the IR.There is no relationship between slick thicknessand the intensity of the IR image.In the daytime, thick oil is hotter than water and oilof intermediate thickness is cooler. (The cross ov
35、erwith water occurs when the oil is about 20 to150 m thick.B) At night this relationship reverses(unless the spill is fresh and the oil is hotter thanthe water when it arrives at the surface).This results in two periods per day with poordiscrimination.Ultraviolet Oil is highly reflective in the ultr
36、aviolet (UV200to 400 nm).Very thin (10 nm) layers of oil can be detectedin the UV.CThus, even sheen, a common regu-latory definition of oil pollution, can be delin-eated.UV cameras have fairly good resolution,are light-weight and have minimal powerdemands.High UV reflectance is not unique to oil. Su
37、n glint,biogenic and other materials and phenomena canyield strong returns in the UV.This technology is limited to available lightsituations, and is best used in combinationwith other sensors, typically IR.Radar Oil has a damping effect on high frequency, lowamplitude (1 to 10 cm) capillary waves. T
38、hesewaves, yielding a “rougher” surface, returnconsiderably more radar energy to the receiverthan calm water. As such, under the properconditions, oil can appear as a low return, darkarea in a larger, bright field of un-oiled waves.Specially tuned Side Looking Airborne Radar(SLAR) and Synthetic Aper
39、ture Radar (SAR)are the only two types suited to the oil detectiontask. Search and weather radars can not be usedin this role.Radar has some unique advantages over otheroil spill sensors: it can operate day or night; itcan operate in times of reduced visibility; it canoperate at higher, safer and mo
40、re fuel-efficientaltitudes, and; it is outward, rather than down-wardlooking, making it the only area searchtechnology available for oil spills. Typicalranges are 10 to 50 km.Oil is not the only source of calms. Other, naturallyoccurring substances and phenomena can giverise to smooth water.DIf the
41、prevailing wind is lessthan about 1.5 m/s, there will not be enough“roughness” in un-oiled water to create thenecessary roughness contrast. Likewise, aboveabout 6 m/s the calming effect of, at least thin,oil begins to wash out.EThe potential for falsepositives is high.Radar equipment is expensive an
42、d it requires fairlyextensive modifications to an aircraft, thus addingto both the acquisition and the operational costs.MicrowaveRadiometerOil is a stronger emitter of microwave radiationthan water (emissivity factor of 0.8 versus 0.4,respectively).FTherefore it shows up as a brightarea against a d
43、arker background.The passive microwave radiometer has beendemonstrated to detect oil on water even underlow visibility conditions.The technology is subject to the same limitationsas radar.This is an evolving technique requiring additionaldevelopment and demonstration before acommercial unit is marke
44、table.Current units are installed in dedicated aircraft andthis trend is likely to continue in the near term.Fluoro-sensorsOil targeted or illuminated with UV lightwill adsorb this energy and re-emit, or fluoresce,in the visible band. Other materials fluoresce aswell, but there is enough spectral un
45、iquenessto oil to render it readily discernable. In fact it ispossible that various generic types of oil andpetroleum products can be differentiated.The coherent light from a laser permits thedelivery of more energy from greater distancesmaking an airborne fluorosensors feasible.The laser fluorosens
46、or permits the positiveidentification of oil and even permits somediscrimination between types of oil.It appears to be the only sensor available todaythat permits the detection of oil against complexbackgrounds as is the case with oil on beachesand in, or with, the ice.Laser fluorosensors are fairly
47、 bulky andrequire significant modifications to relatively large,dedicated aircraft.AFingas, M. F. and Brown, C., “Oil Spill Remote Sensing:AForensicApproach,” Chapter 14 in Oil Spill Environmental Forensics: Fingerprinting and Source Identification,Z. Wang and S. Stout, Eds., Academic Press, Amsterd
48、am, 2007, pp. 419447.Bibid.CFingas, M. F. and Brown, C. E., “An Update on Oil Spill Remote Sensors,” in Proceedings of the Twenty-eighth Arctic and Marine Oil Spill Program Technical Seminar,Environment Canada, Ottawa, Ontario, 2005, pp. 825860.DFrysinger, G. S., Asher, W. E., Korenowski, G. M., Bar
49、ger, W. R., Klusty, M. A., Frew, N. M., and Nelson, R. K., “Study of Ocean Slicks by Nonlinear Laser Processesin Second Harmonic Generation,” Journal of Geophysical Research, 1992.EWisman, V., Alpers, W., Theis, R., and Hhnerfuss, H., “The Damping of Short Gravity-Capillary Waves by Monomolecular Sea Slicks Measured by AirborneMulti-frequency Radars,” Journal of Geophysical Research, 1993.FUlbay, F. T., Moore, R. K., and Fung, A. K., Microwave Remote Sensing: Active and Passive, ArchtHous, Inc., 1989.F2327083ASTM International takes no position respecting the validity
