The application of remote sensing techniques to create a Black Sea coastal response strategy for oil spill response R. Urban & W. Hanlon f OC7, JOO AW/z lee Areef, Awfe 207 Abstract The application of remote satellite imaging, coupled with Geographic Information System (GIS) technology has been used to create coastal maps enhanced with environmental information. The use of such techniques for oil spill response requires the development of practical applications to assist responders with real-time decision making. In a joint effort with regional navies for Black Sea spill contingency planning, the US Navy has developed methods by which a quick, accurate, and economical application of existing technology can be used to produce data rich maps for a large area of interest. This combines various existing techniques to create practical applications and usable documents for oil spill planners and responders. Existing environmental data on a selected area of the Black Sea coastal zone was collected and this information was sorted, harmonized and transposed onto a rectified multispectral satellite image of the area in a GIS format. Multispectral analysis was performed on the image to locate environmentally distinct zones. The resulting multi-layered GIS map provides a useful representation of coastal environmental sensitivities, and in many ways surpasses conventional GIS systems. The satellite image provides an accurate and realtime map of the area while the multispectral data precisely locates common ecosystems, such as wetlands and forests. This allows for the rapid prioritization of coastal areas and the ability to pinpoint specific areas for protection. The resulting process provides emergency responders the ability to quickly and economically create a data rich GIS. This system will provide reliable, timely information for protection strategies, identifying environmental and public risks, and offer a basis by which to measure spill impacts and recovery techniques, especially in areas where environmental reference data is limited.
304 Oil & Hydrocarbon Spills, Modelling, Analysis & Control 1 Introduction The Black Sea is recognized as an ecologically important area, and the advent of its environmental degredation has brought a strong international effort to protect the Black Sea from further ecological harm (Platt [1]). The US Navy, in its effort to contribute to the international effort to protect the Black Sea, is creating a Geographical Information System (CIS) for oil spill planners and responders. This GIS combines current Black Sea environmental data, country specific information, and information derived from satellite imagery. GIS was chosen because it has proved to be an effective method in strategizing oil spill response. Planning and responding to oil spills requires attention to spatial considerations and GIS technology provides a mechanism for maintaining spatial data in dynamic environments and enables the power of spatial associations to be more fully realized (Penland, et al. [2]). Secondly, oil spill response necessitates strong temporal considerations, and a GIS allows quick 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 planners determine the ability of regional assets to respond to these scenarios. Finally, the GIS system will allow the planners to take environmental considerations into the planning of naval activities and exercises. The Black Sea GIS went through five phases of development: 1. Environmental Information Collection 2. Study Area Selection 3. Satellite imagery Classification 4. Country Specific Information Collection 5. GIS Formation 2 Environmental Information Collection The collection of environmental information for the Black Sea coastal region was a concern because of the lack of a harmonized environmental data sets. An abundance 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 thus tasked to use their extensive environmental data resources to compile the first complete harmonized set of environmental data for the Black Sea region on the following subjects: 1. Important Coastal Wetlands of the Black Sea 2. Important Bird Areas along the Black Sea 3. Coastal Protected areas of the Black Sea 4. Endangered Animal Species of Black Sea States 5. 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 of different 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 the boundaries of environmentally sensitive areas. The vector format for this data representation describes the features in lines and points allowing for it to be easily combined with other data sets as well as to allow for manipulation if correction was needed. The boundary vector information includes National Parks, Ramsar sites, World Heritage Sites, recognized important bird areas and recognized important wetlands. Information gaps were identified during the data collection effort are as follows : 1. It was possible to gather good data on the wetland habitats of the Black Sea and important bird areas, but it was not possible to research other important habitats (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 and international importance etc.) was available in some cases but not all. 3. It was possible to produce general lists of endangered species in the six Black Sea nations, but it was not possible to separate coastal from non-coastal species. Such gaps were anticipated as the resources to conduct this study were limited. However, recommendations were made as to how to improve the information in order tofillthe gaps. 3 Study Area Selection A study area for this project was identified as the Black Sea coast of Bulgaria and Turkey. This area was chosen for several reasons. First, an analysis of the information gathered by WCMC indicated that the area contains a number of ecologically important wetlands and national parks. Furthermore, many ships pass this area as they head towards the Bosphorus Straits. All shipping on the Black Sea must travel through the Bosphorus to get to the Mediteranean Sea. This identified coastal region is at greater risk, especially as shipping traffic increases. This area also offered to be a good area that would allow different types of country specific environmental information and information extracted from the satellite imagery to be co-registered. Finally, Landsat TM has a polar orbit, and this region coincided with Landsat TM cloud free image that maximized the coastal area study zone.
306 Oil & Hydrocarbon Spills, Modelling, Analysis & Control 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. The shoreline vector data provided by WCMC was taken from Digital Chart of the World. The Digital Chart of the World dataset was digitized from 1:1,000,000 Operational Navigation Charts and 1:2,000,000 Joint Navigation Charts. This data is adequate for global coverage but lacks detail and accuracy, and so a new shoreline was created for the entire TM scene. Secondly, Landsat TM data contains large amounts of information that can be used to create a regional environmental baseline. This can provide accurate information on the location of environmentally sensitive areas, such as coastal wetlands. Landsat data accomplishes this by analyzing the data from seven TM bands that measures reflectance values of the earth. By analyzing these bands, similar landtypes can be extrapolated from the entire image thus producing a classification of the scene. The classification data can also be used to pinpoint areas for more detailed 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 for the study. The TM scene chosen for the study covered the area from Burgas, Bulgaria southeast to Karaburan, Turkey. Some problems were encountered with obtaining the image from the ground station in Italy where the image was stored because the TM image was corrupted during the transmission from Italy to the US. However, it was decided to use the image because the corruption was minimal 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 two datasets where then co-registered. The vector data was georeferenced and in a geographic projection (latitude and longitude). The vector data was used to provide ground controls so that the imagery could be referenced to the same projection. This was accomplished by selecting multiple ground control points (GCP's). GCP's are locations where there are known coordinates from the source (vector data) that can be seen visibility in the imagery (Narumalani, et. al, [4]). By using several of the vector layers provided by WCMC, enough GCPs were collected to allow for adequate warp of the imagery. Figure 1 shows the georeferenced image where ground control has been applied.
Oil & Hydrocarbon Spills, Modelling, Analysis & Control 307 Figure 1. Georeferenced Landsat TM image Figure 2. Coregistered Landsat and WCMC vector data of Ropotamo Park
308 Oil & Hydrocarbon Spills, Modelling, Analysis & Control Once the image had been georeferenced, all of the vector data and TM imagery was registered to the same coordinate system and projection, as illustrated by Figure 2, Ropotamo National Park in Bulgaria. This allows the datasets to be viewed 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 were done primarily where wetlands areas were known to exist. The vector data provided by WCMC was used to narrow down the areas to be classified thus narrowing the field to these areas. It was now possible to classify the image based on the classification of the analysis of the different Landsat TM bands and narrow down the exact locations of the wetlands to provide a quantitative appraisal (Jensen [5]). Other cover categories were also qualified for the Ropatomo area. The tables below list the area of each land cover type. These values corresponds to the subset areas. Table I. Area of different land cover types of Ropotamo CLASS Wetland Forest Cropland/Pasture Urban/Built-up AREA (acres) 1,098 29,065 10,920 1,217 In Figure 3 we find see that the classification of the Ropatamo park area gives us 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 map information as possible. This includes the infrastructure information that would be required by the responders and planners. This comprises such information as roads, cities, airports, boat ramps, port facilities, and other infrastructure that would add subsequent layers to the Black Sea GIS (Jesson, [6]). For this purpose, we used available information from the U.S. National Imagery and Mapping Agency. Specifically, we used a number of their products including their Digital Nautical Charts, Arc Digitized Raster Graphics, and World Vector Shoreline Plus products. All of these products contained a great amount of varied country specific information which was sorted and compared to the requirements of the responders and planners to determine what was useful, and what was not. The useful information was then to be included in the Black Sea GIS.
Oil & Hydrocarbon Spills, Modelling, Analysis & Control 309 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 gathered information and formed into a functional, multi layered Geographical Information System. ARC/INFO software was able to read all of the information formats used to form the GIS as illustrated in Figure 4. The final product included the base map created by WCMC, the satellite image, and the NIMA information. Also, the textual data from the WCMC report was included in the system as attribute information describing each environmentally distinguished area. Therefore, a responder can choose an area and get instant information on the wildlife, bird nesting information, endangered species, management information, etc. on a certain area. 7 Conclusion GIS, combined with satellite imagery, creates a powerful tool that is able to combine "data islands" into one complete "data continent" that is easy and efficient to use (Clark, [7]). It was also found that environmental data combined with satellite imagery can provide an inexpensive and highly accurate picture of the coastal area.
310 Oil & Hydrocarbon Spills, Modelling, Analysis & Control Black Sea Oil Spill Environmental Sensitivity Mapping Using Remote Sensing and Geographic Information Systems 1 Rectify Thematic Mapper 30x30 m Multispectral Data 2 Contrast Stretched the Rectified Nearinfrared (Band4) for use as a Plammetric Basemap 3 Classify Image to Determine Land Cover Types 4 Mammals, Shellfish, Fish. Bird, and Reptile Distribution Derived from In Situ Data and Placed in ARC-lnfo Database 5 Booms, Skimmers, Boat Ramps, Marinas Planimetric Base map Shoreline Index Information Oil Sensitive Wildlife Information Access & Protection Information 6 Transportation System Including Roads, Railroads. Airports, and all Place Names in ARC-lnfo Database 7 Overlay of: 1) Shoreline Sensitivity Information 2) Oil Sensitive Wildlife Information 3) Access and Protection data onto 30x30 m Thematic Mapper of the Study Area Overlay of Digital Database on Orthophotographic Basemap Figure 4. Schematic diagram showing GIS layer formation and overlay It must be noted that environmental data is not as accurate as the data obtained from ground truthing, but it can provide an excellent first overview that would allow responders to make decisions that would maximize the protection of environmental sensitive resources with a limited amount of response equipment. It also allows the extraction of a precise plannimetric basemap for a coastal area, which can be very useful, especially in many parts of the world were the coastal zone maps are out of date. This method can easily be transferd to any part of the world: we can create a quick, accurate GIS system very quickly that can serve as a response or planning tool. This capability will only increase as new technology, such as hyperspectral and one meter imaging, becomes available.
Oil & Hydrocarbon Spills, Modelling, Analysis & Control 311 References [1] Platt, A., Black Sea : A Sea of Troubles, World Watch, Jan-Feb, pp. 11-18 1995. [2] Penland, S., Wayne, L., MMS Gulf Region GIS Database For Oil Spill Contingency 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 Remote Sensing and Geographic Information Systems, Proc. of 1992 ASPRS-ACSM Annual Convention,^. L. Gleasner, Vol. 2, Albuquerque, New Mexico, pp 157-166, 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 Emirates Using Landsat Thematic Mapper Imagery and GIS Technology, Proc. of 1992 ASPRS-ACSM Annual Convention,^. L. Gleasner, Vol. 2, Albuquerque, New Mexico, 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 Remote Sensing and Geographic Information System Technology, InternationalJournal of Geographical Information Systems, 4(2), 181-201, 1990. [6] Jesson, E., Digital Data Collection Techniques for Land Use and Land Cover: Tacoma and Denver West Prototype Projects, Proc. of 1992 ASPRS- ACSM Annual Convention,^. L. Gleasner, Vol. 2, Albuquerque, New Mexico pp. 188-198, 1992. [7] Clark, J.R., Coastal Zone Management Handbook, CRC Press, Boca Raton, New York, London and Tokyo, pp. 315-318, 1995.