1、Advanced Space Technology for Oil Spill DetectionAbstract Environmental pollution, including oil spill is one of the major ecological problems. Negative human impacts demands to develop appropriate legislations within the national and international framework for marine and coastal environment as wel
2、l as the onshore protection. Several seas, for instance the Mediterranean, the Baltic and the North Seas were declared as special areas where ship discharges are completely prohibited (Satellite Monitoring, LUKOIL).In this regard environmental protection of the Caspian Sea has a priority status for
3、Azerbaijan as a closed water basin ecosystem. This area, as a highly sensitive area in the World requires permanent ecological monitoring services where oil and gas from the subsurface of the Caspian Sea is developing almost more than a century. This status of the Caspian Sea is expected to be reten
4、tion at least for the coming fty years.Remote sensing is a key instrument for successful response to the onshore and offshore oil spills impacts. There is an extreme need for timely recognition of the oil spilled areas with the exact place of location, extent of its oil contamination and verication
5、of predictions of the movement and fate of oil slicks.Black Sea region is expected to have a dramatic increase in the trafc of crude oil (mainly from the Caspian region). The main reason for these changes is the growth of oil industry in both Kazakhstan and Azerbaijan. The real substantial changes i
6、n tanker movements and routs are not clear till now.A necessity for a continuous observation of the marine environment comes afore when clarifying the tendencies of changes in the concentration of the particularly dangerous polluting substances as well as the behavior of different kinds of polluting
7、 substances in the detected area i.e., creation of a system for monitoring the pollution (L.A. Stoyanov and G.D. Balashov, UNISPACE III, Varna, Bulgaria).The exploration of geological and oil production started in the shelf of the Caspian Sea a long time ago. The Caspian Sea is a highly sensitive re
8、gion on ecological and biodiversity point of view. Oil dumps and emergency oil spill have an extremely bad inuence on the marine and earth ecosystem and can lead to the ecological balance.Certainly the general issue of oil and gas pipeline safety includes aspects of natural disasters and problems re
9、lated to the environment. After successful construction of the Baku-Tbilisi-Ceyhan oil pipeline and Baku-Tbilisi-Erzrum gas pipeline these aspects especially became very important for Azerbaijan and denitely, for the region. The Baku-Tbilisi-Ceyhan Crude Oil Export Pipeline comprises a regional crud
10、e oil export transportation system, approximately 1750 in overall length.Generally, oil spill monitoring in the offshore and onshore is carried out by means of specially equipped airborne, ships and satellites. Obviously, daylights and weather conditions limit marine and aerial surveillance of oil s
11、pills.Keywords Space technology. Space image. Oil spil DetectionIntroductionGenerally, oil spillage is categorized into four groups: minor, medium, major and disaster. Minor spill neither takes place when oil discharge is less than 25 barrels in inland waters nor less than 250 barrels on land, the o
12、ffshore or coastal waters that does nor pose a threat to the public health or welfare. In case of the medium spill the spill must be 250 barrels or less in the inland water or from 250 to 2 500 barrels on land, offshore and coastal water while for the major spill, the discharge to the inland waters
13、is in excess of 250 barrels on land, offshore or coastal waters. The disaster refers to any uncontrolled well blowout, pipeline rupture or storage tank failure which poses an immediate threat to public health or welfare.Satellite-based remote sensing equipment installed in the satellite is used for
14、monitoring, detecting and identifying sources of accidental oil spills. Remote sensing devices include the use of infrared, video and photography from airborne platforms. In the mean time presently a number of systems like airborne radar, laser uorescence, microwave radiometer, SAR, ERS 1, ERS 2, EN
15、VISAT and LANDSAT satellite systems are applied for the same purposes. Currently more than a dozen satellites are in the orbit producing petabytes of data daily. Detailed description of these satellites, major characteristics of sensors can be summarized as follows:l Spatial resolution of sensors ra
16、nges from 1 meter (e.g. IKONOS) to several kilo-meters (e.g. GEOS)l Satellite sensors commonly use visible to near-infrared, infrared and microwaveportions of electromagnetic spectrum;l Spectral resolution of satellite data ranges from single band (Radarsat) to multibands (e.g. MODIS with 36 bands)l
17、 Temporal resolution (repeat time) varies from several times a day (e.g. Meteosat)l The majority of satellites are sun synchronous and polar orbiting, crossing the equator at around 10 a.m. local time during their descending passl Digital data are available in both panchromatic (black and white) and
18、 multi- spectral modesUsing the recent advanced space technology, the following methodology can be applied for the oil spills detections:l Development of oil spill detection methods for the purpose of practical oil spill surveillance related to the space imagery with application of any weather condi
19、tions;l Adaptation of the observation to other systems to predict the oil spill spread direction and ow rate characteristics, determination the pollutant contaminations;l Development of appropriate data and user interfaceThere is a need for effectively direct spill countermeasures such as mechanical
20、 containment and recovery, dispersant application and burning, protection of sites along threatened coastlines and the preparation of resources for the shoreline clean-up.As it is mentioned in the beginning, the remote sensing is one of the main methods for an effective response to the oil spills en
21、vironmental monitoring. Timely response to an oil spill requires rapid investigation of the spill site to determine its exact location, extent of oil contamination, oil spill thickness, in particular.Policy makers, managers, scientists and the public can view the changing environment using the satel
22、lite images. Remote sensing is the discipline of observing the Earths surface without direct contact with the objects located at the surface. It allows obtaining information about the planet and human activities from a distance which can reveal interesting features that may not be possible or afford
23、able from the ground level. One of the applications of remote sensing is water and coastal resources. It is essential to undertake the following aspects while using the remote sensing method:l Determination of surface water areasl Monitoring the environmental effects of human activities;l Mapping oo
24、ds and ood plains;l Determination of the extent of snow and ice;l Measuring glacial features;l Mapping shoreline changes;l Tracing oil and pollutions.The fact that remote sensing allows multi-temporal analysis is also very important. This means that an area of interest can be monitored over time so
25、that changes can be detected. It allows analyzing phenomena like vegetation growth during different seasons, the extent of annual oods, the retreat of glaciers or the spread of forest res or oil spills (Vhenenye Okoro, 2004).Remote sensing is a useful method in several modes of oil spill control, in
26、cluding a large scale area of surveillance ability, specic site monitoring and advantages of technical and technological assistance in emergency cases. There is a signicant capacity of providing essential information to enhance strategic and tactical decision-making, decreasing response costs by fac
27、ilitating rapid oil recovery and ultimately minimizing impacts.Observation can be undertaken visually or by using remote sensing systems. In remote sensing, a sensor other than human vision or conventional photography is used to detect or map oil spills.Oil Spill DetectionOil production and transpor
28、tation is started on the offshore “Azeri Chiraq Guneshli” oileld, located at the Azerbaijani sector of the Caspian Sea. Therefore development and implementation of onshore and offshore oil spill monitoring and detection are highly important for the Caspian Sea basin countries. Figure 1 shows the ove
29、rall map of the Caspian Sea region countries.Oil statistics of the major Caspian Sea oil producing countries are presented in Table 1.For visual observations of oil spill from the air using the video photography are the simplest, most common and convenient method of determining the location and exte
30、nt (scale and size) of an oil spill. There are a number of sensors on surveillance of the sea surface:l Microwave radiometers which allow the determination of the oil thickness;l Ultraviolet and infrared scanners which allow to detect respectively very thin and very thick oil lms;l Laser uorescence
31、sensors which allow the determination of oil type.Fig. 1 Overall map of the Caspian Sea region countriesApplication of remote sensing method for spilled oil can be discovered using a helicopter, particularly over near-shore waters where their exibility is an advantage along intricate coasting with c
32、liffs, coves and islands. For the spill response efforts to be focused on the most signicant areas of the spill, it is important to take into consideration relative and heaviest concentrations of oil. Geographical positioning systems (GPS) or other available aircraft positioning systems creates a po
33、sitive environment for localization of the oil location. Photography, particularly digital photography is also a useful instrument as a recording tool. It allows viewing the situation on return to base. Many other devices operating in the visible spectrum wavelength, including the conventional video
34、 camera are available at a reasonable cost. Dedicated remote sensing aircraft often have built-in downward looking cameras linked with a GPS to assign accurate geographic coordinates.In the open ocean spills show a less need for rapid changes in ying speed, direction and altitude, in these instances
35、 the use of low altitude, xed-wing aircraft proved to be the most effective tactical method for obtaining information about spills and assisting in spill response.Oil spill detection is still performed mainly by visual observation which is limited to favorable sea and atmospheric conditions and any
36、operation in rain, fog or darkness is eliminated. Visual observations are restricted to the registration of the spill because there is no mechanism for positive oil detection. Very thin oil sheens are also difcult to detect especially in misty or other conditions that limit vision.Oil is difcult to
37、discover in high seas and among debris or weeds where it can blend in to dark backgrounds such as water, soil or shorelines. Huge naturally occurring substances or phenomena can be mistaken for spilled oil. These include sun glint, wind shadows and wind sheens, biogenic or natural oils from sh and p
38、lants, glacial our (nely, ground mineral material usually from glaciers) and oceanic or revering fronts where two different bodies of water meet. The usefulness of visual observations is limited, however, it is an economical way to document spills and provide baseline data on the extent and movement
39、 of the spilled oil.Estimation of the quantity of oil observed at sea is the main issue for the detection of the oil spill. Observers are generally able to distinguish between sheen and thicker patches of oil. However gauging the oil thickness and coverage is not always easy and it can be more difcu
40、lt if the sea is rough. It is essential to view all such estimates with considerable caution.Purpose of the remote sensing equipment mounted in aircraft is increasingly used to monitor, detect and identify sources of illegal marine discharges and to monitor accidental oil spills. Remote sensing devi
41、ces except infrared video and photography from airborne platforms, thermal infrared imaging, airborne laser uourosensors, airborne and satellite optical sensors use satellite Synthetic Aperture Radar (SAR). Advantages of SAR sensors over optical ones is their ability to provide data in poor weather
42、conditions and during darkness. Remote sensing method operates detecting properties of the surface such as color, reectance, temperature or roughness of the area. Spilled oil can be detected on the surface when it modies one or more of these properties. Cameras relying on visible light are widely us
43、ed and may be supplemented by airborne sensors which detect oil outside the visible spectrum and are thus able to provide additional information about the oil. The most commonly applied combinations of sensors include Side-Looking Airborne Radar (SLAR) and downward-looking thermal infrared and ultra
44、violet detectors or imaging systems.A number of remote sensors placed on Earth observation satellites can also detect spilled oil as well. Optical observation of spilled oil by the satellite requires clear skies, thereby limits the usefulness of such system. SAR is not restricted by the presence of
45、cloud, thus it is a more useful tool. However with radar imagery, it is quite difcult to be certain if an anomalous feature on a satellite image is caused by the presence of oil. Consequently, radar imagery from SAR requires expert interpretation by suitably trained and qualied personnel to avoid ot
46、her features being mistaken for oil spills. However, there is a growing interest of developing SAR to deploy on satellite platforms. Oil on the sea surface dampens some of the small capillary waves that normally are present on clean seas. These capillary waves reect radar energy producing a “bright”
47、 area in radar imagery known as sea clutter. The presence of an oil slick can be detected as a “dark” area or one with the absence of sea clutter. Unfortunately, oil slicks are not the only phenomena that can be detected in similar manner. There are many other interferences including fresh water sli
48、ck, calm areas (wind slicks), wave shadows behind land or structures, vegetation or weed beds that calm the water just above them, glacial our, biogenic oils and whale and sh sperm. SAR satellite imagery showed that several false signals are present in a large number of scenes (Bern et al., 1993; Wa
49、hl et al., 1993). Despite these limitations, radar is an important tool for oil spill remote sensing since it is the only sensor capable of searching large areas. Radars, as active sensors operating in the microwave region of the electromagnetic spectrum are one of the few sensors that can detect at night and through clouds or fog (Schnick S, InSAR and LIDAR, 2001).Oil Spill Monitoring and
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