304 oil & hydrocarbon spills, modelling, analysis & control · 2014-05-18 · oil &...

The application of remote sensing techniques to

create a Black Sea coastal response strategy for

oil spill response

R. Urban & W. Hanlon

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Abstract

The application of remote satellite imaging, coupled with GeographicInformation System (GIS) technology has been used to create coastal mapsenhanced with environmental information. The use of such techniques for oilspill response requires the development of practical applications to assistresponders with real-time decision making. In a joint effort with regional naviesfor Black Sea spill contingency planning, the US Navy has developed methodsby which a quick, accurate, and economical application of existing technologycan be used to produce data rich maps for a large area of interest. Thiscombines various existing techniques to create practical applications and usabledocuments for oil spill planners and responders.

Existing environmental data on a selected area of the Black Sea coastal zonewas collected and this information was sorted, harmonized and transposed ontoa rectified multispectral satellite image of the area in a GIS format.Multispectral analysis was performed on the image to locate environmentallydistinct zones. The resulting multi-layered GIS map provides a usefulrepresentation of coastal environmental sensitivities, and in many wayssurpasses conventional GIS systems. The satellite image provides an accurateand realtime map of the area while the multispectral data precisely locatescommon ecosystems, such as wetlands and forests. This allows for the rapidprioritization of coastal areas and the ability to pinpoint specific areas forprotection.

The resulting process provides emergency responders the ability to quicklyand economically create a data rich GIS. This system will provide reliable,timely information for protection strategies, identifying environmental andpublic risks, and offer a basis by which to measure spill impacts and recoverytechniques, especially in areas where environmental reference data is limited.

Transactions on Ecology and the Environment vol 20, © 1998 WIT Press, www.witpress.com, ISSN 1743-3541

304 Oil & Hydrocarbon Spills, Modelling, Analysis & Control

1 Introduction

The Black Sea is recognized as an ecologically important area, and the advent ofits environmental degredation has brought a strong international effort to protectthe Black Sea from further ecological harm (Platt [1]). The US Navy, in itseffort to contribute to the international effort to protect the Black Sea, is creatinga Geographical Information System (CIS) for oil spill planners and responders.This GIS combines current Black Sea environmental data, country specificinformation, and information derived from satellite imagery.

GIS was chosen because it has proved to be an effective method instrategizing oil spill response. Planning and responding to oil spills requiresattention to spatial considerations and GIS technology provides a mechanism formaintaining spatial data in dynamic environments and enables the power ofspatial associations to be more fully realized (Penland, et al. [2]). Secondly, oilspill response necessitates strong temporal considerations, and a GIS allowsquick and accurate access to information that facilitates the response.

The GIS for the Black Sea will also help oil spill planners to analyze risks.This will allow them to prepare for probable scenarios and will help plannersdetermine the ability of regional assets to respond to these scenarios. Finally,the GIS system will allow the planners to take environmental considerations intothe planning of naval activities and exercises.

The Black Sea GIS went through five phases of development:

1. Environmental Information Collection2. Study Area Selection3. Satellite imagery Classification4. Country Specific Information Collection5. GIS Formation

2 Environmental Information Collection

The collection of environmental information for the Black Sea coastal regionwas a concern because of the lack of a harmonized environmental data sets. Anabundance of Black Sea environmental data exists; but in different formats,languagues and countries around the Black Sea and the world.

The World Conservation Monitoring Centre in Cambridge, UK was thustasked to use their extensive environmental data resources to compile the firstcomplete harmonized set of environmental data for the Black Sea region on thefollowing subjects:

1. Important Coastal Wetlands of the Black Sea2. Important Bird Areas along the Black Sea3. Coastal Protected areas of the Black Sea4. Endangered Animal Species of Black Sea States5. Endangered Plant Species of Black Sea States


Oil & Hydrocarbon Spills, Modelling, Analysis & Control 305

6. International Conventions and Agreements covering the Black Sea Coast

The information on each of these subjects was collected from a wide range ofdifferent sources and was delineated by country when possible.WCMC then created a vector map of the Black Sea Coastal area (from

littoral zone to 50 miles inland) that contained polygons representing theboundaries of environmentally sensitive areas. The vector format for this datarepresentation describes the features in lines and points allowing for it to beeasily combined with other data sets as well as to allow for manipulation ifcorrection was needed. The boundary vector information includes NationalParks, Ramsar sites, World Heritage Sites, recognized important bird areas andrecognized important wetlands.

Information gaps were identified during the data collection effort are asfollows :

1. It was possible to gather good data on the wetland habitats of the BlackSea and important bird areas, but it was not possible to research other importanthabitats (e.g. seagrass, sand dunes, beaches).

2. Protected areas are listed by name, size, and location, where possible.More detailed information (on management status, boundaries, national andinternational importance etc.) was available in some cases but not all.

3. It was possible to produce general lists of endangered species in the sixBlack Sea nations, but it was not possible to separate coastal from non-coastalspecies.

Such gaps were anticipated as the resources to conduct this study werelimited. However, recommendations were made as to how to improve theinformation in order to fill the gaps.

3 Study Area Selection

A study area for this project was identified as the Black Sea coast of Bulgariaand Turkey. This area was chosen for several reasons. First, an analysis of theinformation gathered by WCMC indicated that the area contains a number ofecologically important wetlands and national parks. Furthermore, many shipspass this area as they head towards the Bosphorus Straits. All shipping on theBlack Sea must travel through the Bosphorus to get to the Mediteranean Sea.This identified coastal region is at greater risk, especially as shipping trafficincreases. This area also offered to be a good area that would allow differenttypes of country specific environmental information and information extractedfrom the satellite imagery to be co-registered. Finally, Landsat TM has a polarorbit, and this region coincided with Landsat TM cloud free image thatmaximized the coastal area study zone.



4 Satellite Imagery

The use of satellite imagery is a critical piece of the Black Sea GIS. First,satellite imagery allows for an accurate and up-to date planimetric basemap. Theshoreline vector data provided by WCMC was taken from Digital Chart of theWorld. The Digital Chart of the World dataset was digitized from 1:1,000,000Operational Navigation Charts and 1:2,000,000 Joint Navigation Charts. Thisdata is adequate for global coverage but lacks detail and accuracy, and so a newshoreline was created for the entire TM scene. Secondly, Landsat TM datacontains large amounts of information that can be used to create a regionalenvironmental baseline. This can provide accurate information on the locationof environmentally sensitive areas, such as coastal wetlands. Landsat dataaccomplishes this by analyzing the data from seven TM bands that measuresreflectance values of the earth. By analyzing these bands, similar landtypes canbe extrapolated from the entire image thus producing a classification of thescene. The classification data can also be used to pinpoint areas for moredetailed investigation (Jakbauskas, [3]).

4.1 Image acquisition

Landsat Thematic Mapper (TM) data that was acquired by Space Imaging -EOSAT of Thorton, Colorado. An image taken on June 24, 1997 was used forthe study.

The TM scene chosen for the study covered the area from Burgas, Bulgariasoutheast to Karaburan, Turkey. Some problems were encountered withobtaining the image from the ground station in Italy where the image was storedbecause the TM image was corrupted during the transmission from Italy to theUS. However, it was decided to use the image because the corruption wasminimal and it had little effect on the ability to extract data from the image

4.2 Data co-registration

Vector data from WCMC was then imported by Space Imaging, and the twodatasets where then co-registered. The vector data was georeferenced and in ageographic projection (latitude and longitude). The vector data was used toprovide ground controls so that the imagery could be referenced to the sameprojection. This was accomplished by selecting multiple ground control points(GCP's). GCP's are locations where there are known coordinates from thesource (vector data) that can be seen visibility in the imagery (Narumalani, et.al, [4]). By using several of the vector layers provided by WCMC, enoughGCPs were collected to allow for adequate warp of the imagery. Figure 1 showsthe georeferenced image where ground control has been applied.



Figure 1. Georeferenced Landsat TM image

Figure 2. Coregistered Landsat and WCMC vector data of Ropotamo Park



Once the image had been georeferenced, all of the vector data and TM imagerywas registered to the same coordinate system and projection, as illustrated byFigure 2, Ropotamo National Park in Bulgaria. This allows the datasets to beviewed concurrently, at the proper scale and in the correct geographic location.

4.3 Multispectral analysis

The image was then processed and a multispectral classification was performed.A land cover map is the result of such a classification. The classifications weredone primarily where wetlands areas were known to exist. The vector dataprovided by WCMC was used to narrow down the areas to be classified thusnarrowing the field to these areas.

It was now possible to classify the image based on the classification of theanalysis of the different Landsat TM bands and narrow down the exact locationsof the wetlands to provide a quantitative appraisal (Jensen [5]). Other covercategories were also qualified for the Ropatomo area. The tables below list thearea of each land cover type. These values corresponds to the subset areas.

Table I. Area of different land cover types of Ropotamo

CLASSWetlandForestCropland/PastureUrban/Built-up

AREA (acres)1,09829,06510,9201,217

In Figure 3 we find see that the classification of the Ropatamo park area givesus a precise location of the sensitive wetland areas.

5 Country Specific Information

It was also important that the GIS include as much country specific base mapinformation as possible. This includes the infrastructure information that wouldbe required by the responders and planners. This comprises such information asroads, cities, airports, boat ramps, port facilities, and other infrastructure thatwould add subsequent layers to the Black Sea GIS (Jesson, [6]).

For this purpose, we used available information from the U.S. NationalImagery and Mapping Agency. Specifically, we used a number of theirproducts including their Digital Nautical Charts, Arc Digitized Raster Graphics,and World Vector Shoreline Plus products. All of these products contained agreat amount of varied country specific information which was sorted andcompared to the requirements of the responders and planners to determine whatwas useful, and what was not. The useful information was then to be includedin the Black Sea GIS.



Figure 3. Coastal Wetlands Identified by TM Image Classification

6 GIS Compilation

The formation of the final GIS was a method of combining all the gatheredinformation and formed into a functional, multi layered GeographicalInformation System. ARC/INFO software was able to read all of theinformation formats used to form the GIS as illustrated in Figure 4.

The final product included the base map created by WCMC, the satelliteimage, and the NIMA information. Also, the textual data from the WCMCreport was included in the system as attribute information describing eachenvironmentally distinguished area. Therefore, a responder can choose an areaand get instant information on the wildlife, bird nesting information, endangeredspecies, management information, etc. on a certain area.

7 Conclusion

GIS, combined with satellite imagery, creates a powerful tool that is able tocombine "data islands" into one complete "data continent" that is easy andefficient to use (Clark, [7]). It was also found that environmental data combinedwith satellite imagery can provide an inexpensive and highly accurate picture ofthe coastal area.



Black Sea Oil Spill Environmental Sensitivity Mapping UsingRemote Sensing and Geographic Information Systems

1 Rectify Thematic Mapper 30x30 mMultispectral Data

2 Contrast Stretched the Rectified Near-infrared (Band4) for use as a PlammetricBasemap

3 Classify Image to Determine LandCover Types

4 Mammals, Shellfish, Fish. Bird, and ReptileDistribution Derived from In Situ Data andPlaced in ARC-lnfo Database

5 Booms, Skimmers, Boat Ramps,Marinas

6 Transportation System Including Roads,Railroads. Airports, and all Place Namesin ARC-lnfo Database

7 Overlay of:1) Shoreline Sensitivity

Information2) Oil Sensitive Wildlife

Information3) Access and Protection data

onto 30x30 m Thematic Mapperof the Study Area

PlanimetricBase map

Shoreline IndexInformation

Oil SensitiveWildlife Information

Access & ProtectionInformation

Overlay of DigitalDatabase on

OrthophotographicBasemap

Figure 4. Schematic diagram showing GIS layer formation and overlay

It must be noted that environmental data is not as accurate as the dataobtained from ground truthing, but it can provide an excellent first overview thatwould allow responders to make decisions that would maximize the protectionof environmental sensitive resources with a limited amount of responseequipment. It also allows the extraction of a precise plannimetric basemap for acoastal area, which can be very useful, especially in many parts of the worldwere the coastal zone maps are out of date.

This method can easily be transferd to any part of the world: we can create aquick, accurate GIS system very quickly that can serve as a response or planningtool. This capability will only increase as new technology, such ashyperspectral and one meter imaging, becomes available.



References

[1] Platt, A., Black Sea : A Sea of Troubles, World Watch, Jan-Feb, pp. 11-181995.

[2] Penland, S., Wayne, L., MMS Gulf Region GIS Database For Oil SpillContingency Planning, froc. q/V/%? /PPJ Wev?7a//oW O//S/?/// Oo/7/gn?Mce,eds. J.O. Ludwigson, Long Beach, California, pp. 851-852, 1995.

[3] Jakubauskas, M., Modeling Endangered Bird Species Habitat with RemoteSensing and Geographic Information Systems, Proc. of 1992 ASPRS-ACSMAnnual Convention,̂ . L. Gleasner, Vol. 2, Albuquerque, New Mexico, pp157-166, 1992.

[4] Narumalani, S., Jensen, J.R., Weatherbee, O., Murday, M., and Sexton,W.J., Coastal Sensitivity Mapping For Oil Spills in the United Arab EmiratesUsing Landsat Thematic Mapper Imagery and GIS Technology, Proc. of 1992ASPRS-ACSM Annual Convention,̂ . L. Gleasner, Vol. 2, Albuquerque, NewMexico, pp. 314-319, 1992.

[5] Jensen, J.R., Ramsey, E.W., Holmes, J.M., Savitsky, B., & Davis, B.A.,Environmental Sensitivity Index (ESI) mapping for Oil Spills Using RemoteSensing and Geographic Information System Technology, InternationalJournalof Geographical Information Systems, 4(2), 181-201, 1990.

[6] Jesson, E., Digital Data Collection Techniques for Land Use and LandCover: Tacoma and Denver West Prototype Projects, Proc. of 1992 ASPRS-ACSM Annual Convention,̂ . L. Gleasner, Vol. 2, Albuquerque, New Mexicopp. 188-198, 1992.

[7] Clark, J.R., Coastal Zone Management Handbook, CRC Press, Boca Raton,New York, London and Tokyo, pp. 315-318, 1995.


304 oil & hydrocarbon spills, modelling, analysis & control · 2014-05-18 · oil &...

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