Sea Technology

MAR 2018

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18 ST | March 2018 www.sea-technology.com R emote sensing is the only technology available for obtaining a synoptic view of large areas, uniformly in time and space, so it is well suited to coastal monitoring. The coast is a unique nat- ural environment between the sea and the land surface, and destruction and damage occur to coastal areas due to improper usage, which adversely affects the balance of nature. Approximately 60 percent of the world's pop- ulation lives on coasts and in coastal environmental systems, and a large number of cities are located near harbors and ports. In Turkey, the length of the main shoreline is 7,266 km, and there are a further 1,067 km of island shores, making a total length of 8,333 km. The distribution of the length of these coasts is as follows: the Black Sea, 1,701 km (20.4 percent); the Sea of Marmara, 1,441 km (17.3 percent); the Aegean Sea, 3,484 km (41.8 percent); and the Mediterranean, 1,707 km (20.5 percent). Coastal areas are exposed to environmental and so- cioeconomic pressures, such as settlements, agriculture, tourism, climate changes, natural disasters and sea acci- dents, over both the short and long term. Changes may result from natural causes, including geomorphological structures, changes in sea levels, coastal slope, wave height, tides and groundwater level, as well as human impacts, such as sand extraction, urbanization, land use and groundwater usage. Current pressures are increasing coastal zone vulner- ability, and the detection of changes to coastal areas can be used as the basis for generating usage policy and vul- nerability maps of coastal areas. In this study, temporal shoreline changes have been studied in the northern part of the Black Sea coast near Istanbul, which includes the Kilyos Saritepe Campus of Bogazici University, using Landsat images captured be- tween 1986 and 2015. Data Sets In this study, Landsat 5 and Landsat 7 satellite images have been used to monitor the coastline changes that have oc- curred at Kilyos Saritepe Campus. All the satellite images are dated between August 5, 1986 and August 31, 2007 for Landsat 5 and between July 21, 2001 and July 28, 2015 for Landsat 7. All the Landsat 5 and Landsat 7 sat- ellite images were downloaded from the U.S. Geologi- cal Survey website (https://landsat.usgs.gov) and possess 30-m spatial resolution with 11-byte radiometric resolu- tion. Before downloading the satellite images, some signifi- cant standards were determined and defined. All satellite images were obtained from the same season in order to minimize the phenological effect. A further important pa- rameter was that all the images have low cloud coverage in order to eliminate errors due to radiometric and atmo- spheric conditions. Study Area The study area is situated in Istanbul in the Marmara region of Turkey, at the border of the Bogazici Univer- sity Saritepe Campus near Kilyos on the Black Sea. Is- tanbul is the most populated city in Turkey, covering a total area of approximately 5,450 sq. km and, according to the 2013 census, containing a population of approxi- mately 14 million. The coordinates of the study area are: 41o14'44.29" N to 41o14'47.99" N and 29o0'51.41" E to 29o0'20.74" E, and the study area is 50 km west of the Strait of Istanbul. Methodology A remote-sensing application was used to classify the satellite images and determine changes to the study area. In the last 20 years, remote-sensing applications have become commonly used methods for land use/land cov- Analyzing Changes in Coastal Areas Using Satellite Data Landsat Images Enable Coastal Monitoring on Istanbul's Coast By Asli Sabuncu • Dr. Asli Dogru • Dr. Haluk Ozener 1986-2001 2001-2007 2007-2015 1986-2015 Class/Year Area Diff. (km 2 ) Area Diff. (km 2 ) Area Diff. (km 2 ) Area Diff. (km 2 ) Coast + 0.1989 - 5,1768 - 2,7117 - 7,6896 The area differences for the coast between 1986 and 2015.

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