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Öğe A map Mash-Up application: Investigation the temporal effects of climate change on Salt Lake Basin(Copernicus Gesellschaft MBH, 2016) Kırtıloğlu, Osman Sami; Orhan, Osman; Ekercin, Semih; Halounova, L; Safar, V; Jiang, J; Olesovska, H; Dvoracek, P; Holland, D; Seredovich, VA; Muller, JP; Rao, EPR; Veenendaal, B; Mu, L; Zlatanova, S; Oberst, J; Yang, CP; Ban, Y; Stylianidis, S; Vozenlek, V; Vondrakova, A; Gartner, G; Remondino, F; Doytsher, Y; Percivall, G; Schreier, G; Dowman, I; Streilein, A; Ernst, JThe main purpose of this paper is to investigate climate change effects that have been occurred at the beginning of the twenty-first century at the Konya Closed Basin (KCB) located in the semi-arid central Anatolian region of Turkey and particularly in Salt Lake region where many major wetlands located in and situated in KCB and to share the analysis results online in a Web Geographical Information System (GIS) environment. 71 Landsat 5-TM, 7-ETM+ and 8-OLI images and meteorological data obtained from 10 meteorological stations have been used at the scope of this work. 56 of Landsat images have been used for extraction of Salt Lake surface area through multi-temporal Landsat imagery collected from 2000 to 2014 in Salt lake basin. 15 of Landsat images have been used to make thematic maps of Normalised Difference Vegetation Index (NDVI) in KCB, and 10 meteorological stations data has been used to generate the Standardized Precipitation Index (SPI), which was used in drought studies. For the purpose of visualizing and sharing the results, a Web GIS-like environment has been established by using Google Maps and its useful data storage and manipulating product Fusion Tables which are all Google's free of charge Web service elements. The infrastructure of web application includes HTML5, CSS3, JavaScript, Google Maps API V3 and Google Fusion Tables API technologies. These technologies make it possible to make effective "Map Mash-Ups" involving an embedded Google Map in a Web page, storing the spatial or tabular data in Fusion Tables and add this data as a map layer on embedded map. The analysing process and map mash-up application have been discussed in detail as the main sections of this paper.Öğe An application of landsat-5tm image data for water quality mapping in Lake Beysehir, Turkey(Springer, 2010) Nas, Bilgehan; Ekercin, Semih; Karabörk, Hakan; Berktay, Ali; Mulla, David J.The main goal of this study was to investigate spatial patterns in water quality in Lake Beysehir, which is the largest freshwater reservoir in Turkey, by using Landsat-5TM (Thematic Mapper) data and ground surveys. Suspended sediment (SS), turbidity, Secchi disk depth (SDD), and chlorophyll-a (chl-a) data were collected from 40 sampling stations in August, 2006. Spatial patterns in these parameters were estimated using bivariate and multiple regression (MR) techniques based on Landsat-5TM multispectral data and water quality sampling data. Single TM bands, band ratios, and combinations of TM bands were estimated and correlated with the measured water quality parameters. The best regression models showed that the measured and estimated values of water quality parameters were in good agreement (0.60 < R (2) < 0.71). TM3 provided a significant relationship (R (2) = 0.67, p < 0.0001) with SS concentration. MR between chl-a and various combinations of TM bands showed that TM1, TM2, and TM4 are strongly correlated with measured chl-a concentrations (R (2) = 0.60, p < 0.0001). MR of turbidity showed that TM1, TM2, and TM3 explain 60% (p < 0.0001) of the variance in turbidity. MR of SDD showed a strong relationship with measured SDD, with R (2) = 0.71 (p < 0.0001) for the ratio TM1/TM3 and TM1 band combinations. The spatial distribution maps present apparent spatial variations of selected parameters for the study area covering the largest freshwater lake and drinking water reservoir in Turkey. Interpretation of thematic water quality maps indicated similar spatial distributions for SS, turbidity, and SDD. A large area in the middle portion of the lake showed very low chl-a concentrations as it is far from point and nonpoint sources of incoming nutrients. The trophic state index values were calculated from chl-a and SDD measurements. Lake Beysehir was classified as a mesotrophic or eutrophic lake according to chl-a or SDD parameters, respectively.Öğe An assessment of water reserve changes in Salt Lake, Turkey, through multi?temporal Landsat imagery and real?time ground surveys(Wiley-Blackwell, 2007) Örmeci, Cankut; Ekercin, SemihThis paper focuses mainly on the investigation of water reserve changes in Salt Lake, Turkey, using remote?sensing data. The study is performed in two stages: (1) correlation analysis for real?time ground and satellite data and (2) assessment of water reserve changes using multi?temporal Landsat imagery. First, correlation analysis is conducted to investigate the relationship between digital data from Landsat?5 TM and spectral (in situ) measurements collected using a field spectroradiometer on the same day and time. A radiometric correction procedure, including conversions from digital numbers to radiance and from radiance to at?satellite reflectance, is executed to make satellite data comparable to in situ measurements. This procedure show that simultaneous ground and satellite remote?sensing data are highly correlated (0·84 > R2 > 97) and the near?infrared region (for this study TM4?Landsat?5 TM, band 4) is the best spectral range to distinguish salt and water on the satellite data for the multi?temporal analysis of the water reserve in Salt Lake. It also shows that the use of shortwave infrared band(s) will result in confusion for the determination of the water reserve in this water?covered study area. In a second and last phase, the water reserve change in the lake is examined using multi?temporal Landsat imagery collected in 1990, 2001 and 2005. The remotely sensed, sampled and treated data show that the water reserve in the lake has decreased markedly between 1990 and 2005 due to drought and uncontrolled water usage. It is suggested that the use of water supplies around Salt Lake should be controlled and that the lake should regularly be monitored by up?to?date remote?sensing data (at least annually) for better management of water resources.Öğe Channel regulation monitoring along the Lower Meric River, Turkey, using Landsat-7 enhanced thematic mapper data(Coastal Education & Research Foundation, 2008) Örmeci, Cankut; Ekercin, SemihRiver channelization is a widespread practice including river bed regulation worldwide. A primary goal of channelization is to rehabilitate the floodplain of rivers, modifying the energy regime and sediment transport capacity. This paper presents an application of this process carried out in the floodplain of the Lower Meric River, Turkey. The application was performed by constructing a new channel in two regions along the river in the 1970s. Thus, the river was straightened, isolating its meanders to reduce the floods. These channel regulations are summarized in the paper by using satellite data and historical maps. The Landsat-7 enhanced thematic mapper (2001) image is the base data for interpretation of the present condition of the river channel, and the historical geomorphologic maps are used for the detection of the river bed prior to channelization.Öğe Determination of recent tectonic deformations along the Tuz Gölü Fault Zone in Central Anatolia (Turkey) with GNSS observations(TUBITAK, 2022) Gezgin, Cemil; Ekercin, Semih; Tiryakioğlu, İbrahim; Aktuğ, Bahadır; Erdoğan, Hediye; Gürbüz, Esra; Orhan, Osman; Bilgilioğlu, Süleyman Sefa; Torun, Ahmet Tarık; Gündüz, Halil İbrahim; Oktar, Osman; Türkmen, Cezmi; Kaya, EfdalThe Tuz Gölü Fault Zone (TGFZ) is one of the most important active tectonic structures of Central Anatolia. The morphotectonic features of the TGFZ and the distribution of the epicenters of earthquakes over magnitude 5.0 show that this fault zone remains active today. In this study, the deformation of the TGFZ is determined with high sensitivity using geodetic measurements. To obtain accurate information about the deformation of the TGFZ, 24 GNSS sites and two continuously operating reference stations were constructed in the southern part of the TGFZ. Between 2018 and 2020, Global Navigation Satellite Systems (GNSS) measurements were made on this network. The data of the Turkish National Fundamental GPS Network (TNFGN) and the continuously operating reference stations-Turkey (CORS-TR) sites around the study area were also included in the study, and GNSS measurements were evaluated with the GAMIT/GLOBK software, and velocity fields of the region were determined. In addition, block modeling of the study area was calculated using the GeodSuit software. For the first time, slip rates provided by the geodetic network are established directly on the TGFZ segments, filling a significant deficiency in the literature, contributing to understanding the tectonics of the country and the region, and providing an important dataset for evaluating the degree of seismic activity of the fault zone. The slip rates obtained within the scope of this study are approximately 1.8 mm/yr strike-slip and 2 mm/yr dip-slip for the Acıpınar and Helvadere segments on that Aksaray city is built on. These results indicate that the active deformation in the TGFZ is greater than previously expressed compared to the slip rates calculated in previous studies.Öğe Diversity and abundance of climbers in relation to their hosts and elevation in the monsoon forests of Murree in the Himalayas(Pakistan Botanical Society, 2020) Rahman, Amjad Ur; Khan, Shujahul Mulk; Saqib, Zafeer; Ullah, Zahid; Ahmad, Zeeshan; Ekercin, Semih; Mumtaz, Abdul Samad; Ahmad, HabibClimbers play diverse roles in the biology of forests. Climber species due to its fragile nature are sustible to any change in the forests. Knowledge about climber species in the forests is relatively inadequate and this is the first effort to report the climber plant species in Pakistan. Ecological methods were used to find out climbers abundance, distribution and their relationship with trees/ shrubs in five 1-ha plot range of 735 m to 1754 m elevation at sea level at five localities viz., Baroha, Ghoragali, Numbal, Patriata and Salgaran in the Murree Forests in Western Himalaya, Pakistan during the year of 2016-2017. An overall 3400 climbing plants belonging to 23 species, 19 genera and 13 families were identified and described. Apocynaceae (22%) was the most leading family followed by Ranunculaceae (13%) Rosaceae (13%) and Menispermaceae (9%). Based on our findings the climber species are classified into four classes based on their habit/ form as well. The dominant class was represented by twining climbing mode (43%) followed by woody (30.4%) and hook mode (22%) while tendrils (4.3%) were rare. The abundance and distribution of climber plants were affected by parameters like biotic factors (collection pressure, grazing pressure and No. of hosts) and abiotic factors (topographic and edaphic). Canonical Corresponding Analysis (CCA) indicated that grazing and collection pressures along with elevation were the most important factors influencing the distribution and abundances of climbers. Documentation of the climbers is imperative in the context of increasing forest disturbances, deforestation and fragmentation of forest habitat. Current study will lead towards many other detail studies on climbers in near future.Öğe Estimating soil salinity using satellite remote sensing data and real-time field sampling(Mary Ann Liebert Inc, 2008) Ekercin, Semih; Örmeci, CankutThis paper presents a new algorithm for estimating the salinity level of soil by using satellite remote sensing data. The study includes a real-time field work performed during the overpass of Landsat-5 satellite on 20/06/2006 over Salt Lake, Turkey. Electrical conductivity (EC) is used as indicator of salinity for developing algorithm by using multiple regression technique. In the image processing step, geometric and radiometric correction procedures are conducted to make satellite remote sensing data comparable with the spectral ground measurements carried out using field spectroradiometer supported by hand-held GPS. Results show that real-time ground and satellite remote sensing data are in good agreement with correlation coefficient values of between 0.92 and 0.97. The developed algorithm gives acceptable and meaningful results with a determination coefficient value of 0.95. Finally, the model is tested at a number of individual sample points, and the test results indicate the validation of the developed model with a R-2 value of 0.75.Öğe Evaluating climate change effects on water and salt resources in Salt Lake, Turkey using multitemporal SPOT imagery(Springer, 2010) Ekercin, Semih; Örmeci, CankutThe main goal of this study is to investigate the dimension of climate change effects in Salt Lake and its vicinity in Turkey using satellite remote sensing data. The first stage of the study includes evaluation of the multitemporal climatic data on the Salt Lake Basin Area, Turkey for a period of 35 years (1970-2005). The changes in mean temperature and precipitation are evaluated for the study area by comparing two periods, 1970-1992 and 1993-2005. In the second stage, the effects of climate changes in the Salt Lake are investigated by evaluating water and salt reserve changes through seasonal and multitemporal SPOT imagery collected in 1987 and 2005. The climatic data and remotely sensed and treated satellite images show that water and salt reserve in Salt Lake has decreased between 1987 and 2005 due to drought and uncontrolled water usage. It is suggested that the use of water supplies, especially underground waters, around the Salt Lake should be controlled and the lake should regularly be monitored by current remote sensing data for an effective management of water and salt resources in the region.Öğe Evaluating the effect of external DEMs on the accuracy of InSAR DEM generation(Springer, 2023) Torun, Ahmet Tarık; Ekercin, Semih; Yılmaztürk, Ferruh; Algancı, UğurIn recent years, the production of digital elevation models (DEMs) by using the interferometric synthetic aperture radar (InSAR) technique has become more useful compared to traditional methods. When DEM production is carried out by using this technique, an external DEM is used in the image processing steps. In this study, new DEMs were produced from an interferometric pair of TerraSAR-X images by using SRTM, ALOSW3D, TANDEM-X and STEREO DEMs with spatial resolutions of 90 m, 30 m, 12 m and 5 m, respectively. In addition, in situ measurements were carried out to collect control points and the accuracy of the obtained products was analyzed. The accuracy of the products obtained by using root mean square error, standard deviation and correlation coefficients were compared. The results obtained in this study demonstrated the effect of external DEMs in the DEM production stage with InSAR pairs and how accuracy increases with better external DEMs. In addition, the effect of the external DEM quality used was shown in the results. It was determined that provided the STEREO DEM reached the highest accuracy with the root mean square error value of 1.52 m. Also, analyzes were made according to different zones. According to the results, it was observed that the statistical errors increased in areas where the slope was steeper. While the RMSE of the rolling zone is 1.17 m, rugged zone is 2.33 m. The analysis results of the other DEMs from high to low quality were TANDEM-X, ALOSW3D and SRTM, respectively. It is thought that the results of this study can help to produce data with the required sensitivity in DEM production.Öğe Konya kapalı havzası'ndaki hidrolojik, iklimsel ve arazi kullanımı/örtüsündeki değişimlerin Tuz Gölü'ne etkilerinin araştırılması ve koruyucu yönetim stratejilerinin belirlenmesi(TÜBİTAK ÇAYDAG, 2014) Ekercin, Semih; Topaloğlu, R. Hale; Durduran, Süleyman Savaş; Dadaşer Çelik, Filiz; Helvacı, Esma; Sertel, ElifSon yıllarda artan su talebi nedeniyle, doğal kaynakların yönetimi ve korunması çalışmaları önem kazanmıştır. Bu doğal kaynaklardan birisi de ülkemizin ikinci büyük gölü olan ve Konya Kapalı Havzası’nda yer alan Tuz Gölü’dür. Tuz Gölü’nde tuz üretimi, gölde biriken suyun buharlaşarak tuzun kristalleşmesi esasına dayanmaktadır. Bu nedenle de göldeki su ve tuzla kaplı alanların belirlenmesi ve izlenmesi ülkemiz açısından son derece önemlidir. 1990’lı yıllardan sonra bölgede etkisini artıran kuraklık, bilinçsiz yeraltı suyu çekimi ve Konya Kapalı Havzası’nda açılan kaçak kuyular nedeniyle son yıllarda Tuz gölünün su seviyeleri ve su yüzey alanlarında daralmalar, buna bağlı olarak da tuzla kaplı bölgelerde azalmalar gözlenmektedir.Öğe Landsat-8 uydu görüntüleri kullanılarak hava kalitesi haritasının oluşturulması: Aksaray ili örneği(Milli Savunma Bakanlığı Harita Genel Müdürlüğü, 2020) Gündüz, Halil İbrahim; Ekercin, SemihTüm dünyada olduğu gibi ülkemizde de hızlı nüfus artışının getirdiği artan enerji talebi ve düzensiz yapılaşma, hava kalitesini olumsuz yönde etkilemektedir. Hava kalitesini insan ve diğer canlı organizmaların sağlığını olumsuz yönde etkileyemeyecek seviyelere getirmek için mevcut hava kirliliğinin tespitinin yapılması ve hava kalitesini arttırmaya yönelik önlemlerin alınması gerekmektedir. Teknolojinin gelişmesine paralel olarak uydu sistemlerindeki yenilikler, hava kirliliğine ait parametrelerin belirlenmesi ve mevcut durumun tematik haritasının üretilmesine olanak sağlamaktadır. Bu kapsamda bu çalışmanın temel amacı Aksaray’ın hava kalitesine etki eden PM10 değerlerinin uydu görüntülerinden saptanması ve çalışma alanının PM10 haritasının oluşturulmasıdır. Bu amaç doğrultusunda 16.07.2018 ve 20.10.2018 tarihlerine ait 2 adet Landsat8 uydu görüntüsü ve bu tarihlerde gerçekleştirilen arazi çalışmalarıyla elde edilen PM10 değerleri bu çalışmada temel veri kaynakları olarak kullanılmıştır. Bu veri kaynakları arasındaki ilişkiyi sağlamak amacıyla çoklu regresyon yöntemi kullanılmıştır. Çoklu regresyon analizleri sonucunda elde edilen katsayılar uydu görüntülerine ait red, green ve blue bantlarına uygulanmış ve PM10 ilişkili tematik haritalar üretilmiştir. Üretilen tematik haritalar üzerinde yapılan doğruluk analizi sonucunda iki ölçüm dönemine ait tematik haritaların doğrululukları sırasıyla; %79,64 ve %81,56 olarak bulunmuştur. Elde edilen sonuçlar, uydu görüntüleri yardımıyla hava kirliliğine neden olan PM10’un tespit edilebileceğini göstermektedir. Çalışma alanından elde edilen PM10 değerlerinin, organize sanayi ve şehirlerarası yollarda Dünya Sağlık Örgütünün belirlemiş olduğu sınır değerlerin üzerinde olduğu gözlemlenmiştir.Öğe Mapping chlorophyll-a through in-situ measurements and Terra ASTER satellite data(SPRINGER, 2009) Nas, Bilgehan; Karabörk, Hakan; Ekercin, Semih; Berktay, AliThis paper presents an application of water quality mapping through real-time satellite and ground data. The Lake Beysehir which is the largest freshwater lake and drinking water reservoir in Turkey was selected as the study area. Terra ASTER satellite image is used as remote sensing data source for water quality mapping in addition to simultaneously performed in-situ measurements. Ground data is collected simultaneously with the ASTER overpass on June 09, 2005 over the Lake Beysehir. The spatial distribution map is developed by using multiple regression (MR) technique for water quality parameter, which is chlorophyll-a (chl-a). The results indicate that simultaneous ground and satellite remote sensing data are highly correlated (R (2) > 0.86). In the image processing step, geometric correction, image filtering and development of water quality map procedures are performed with the ERDAS Imagine and ArcGIS 9.0 software. The trophic status of Lake Beysehir is considered to be oligotrophic with an average 1.55 A mu g/l chl-a concentration.Öğe Remote sensing and GIS-based landslide susceptibility mapping using frequency ratio and analytical hierarchy methods in Rize province (NE Turkey)(Springer Nature, 2012) Reis, Selçuk; Atasoy, Mustafa; Nişancı, Recep; Bayrak, Temel; Erduran, Murat; Sancar, Cenap; Ekercin, SemihThe northeast part of Turkey is prone to landslides because of the climatic conditions, as well as geologic and geomorphologic characteristics of the region. Especially, frequent landslides in the Rize province often result in significant damage to people and property. Therefore, in order to mitigate the damage from landslides and help the planners in selecting suitable locations for implementing development projects, especially in large areas, it is necessary to scientifically assess susceptible areas. In this study, the frequency ratio method and the analytical hierarchy process (AHP) were used to produce susceptibility maps. Especially, AHP gives best results because of allowing better structuring of various components, including both objective and subjective aspects and comparing them by a logical and thorough method, which involves a matrix-based pairwise comparison of the contribution of different factors for landslide. For this purpose, lithology, slope angle, slope aspect, land cover, distance to stream, drainage density, and distance to road were considered as landslide causal factors for the study area. The processing of multi-geodata sets was carried out in a raster GIS environment. Lithology was derived from the geological database and additional field studies; slope angle, slope aspect, distance to stream, distance to road and drainage density were invented from digital elevation models; land cover was produced from remote sensing imagery. In the end of study, the results of the analysis were verified using actual landslide location data. The validation results showed satisfactory agreement between the susceptibility map and the existing data on landslide locations.Öğe Seasonal and spatial variability of metals concentrations in Lake Beysehir, Turkey(TAYLOR & FRANCIS LTD, 2009) Nas, Bilgehan; Berktay, Ali; Aygün, Ahmet; Karabork, Hakan; Ekercin, SemihLake Beysehir is the largest fresh water lake and also the largest reservoir for drinking, and irrigation water in Turkey. The lake has an area of 656 km2 with an average depth of 5 m. Metal concentrations of aluminium (Al), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb) and zinc (Zn) were determined in Lake Beysehir on 9 June and 19 August 2005, and 12 June and 22 August 2006. The water samples were collected from 40 sampling stations. The aim of this research is to determine metal concentrations and their seasonal and spatial variability in the lake. Generally, metal concentrations of Lake Beysehir were found to decrease in the sequence of Fe Al Zn Cr Ni Pb Cu Cd as 92.8, 81.8, 7.4, 2.7, 2.2, 1.9, 1.7 and 0.5 g L-1, respectively. The results showed that the mean concentrations of the metals in the lake water did not exceed WHO (World Health Organization), US EPA (Environmental Protection Agency) or TWQCR (Turkish Water Pollution and Control Regulations) drinking water guidelines. On the other hand, maximum levels of metals sporadically exceeded these standards in some sampling stations, especially for Al, Cr, Fe, and Pb.Öğe Tuz Gölü fay zonu (TGFZ) güney kesimine ait tektonik hareketlerin GNSS gözlemleri ile izlenmesi(Afyon Kocatepe Üniversitesi, 2020) Gezgin, Cemil; Tiryakioğlu, İbrahim; Ekercin, Semih; Gürbüz, EsraGünümüzde aktif fayların yakın alanlarına kurulan deformasyon ağlarının GNSS tekniği ile izlenmesi sonucunda depreme ait zamanı belirlemek mümkün olmasa da faylar üzerinde biriken gerilmeler yardımıyla muhtemel deprem konumları tahmin edilebilmektedir. Orta Anadolu Neotektonik Bölgesini, Konya-Eskişehir ve Kayseri-Sivas Neotektonik Bölgeleri olmak üzere iki alt neotektonik bölgeye ayıran bir geçiş zonu olan yaklaşık 220 km uzunluğundaki Tuz Gölü Fay Zonu (TGFZ)’nun kırılması durumunda büyüklüğü (M) yaklaşık 6-7 olan bir depreme sebep olabileceği bilinmektedir. Fay zonunun bu potansiyeli dikkate alınarak, bulunduğu alanda meydana gelen deformasyonların hesaplanması amacıyla Tuz Gölü Fay Zonu’nun Güney Kesiminde doğu-batı yönlü profil şeklinde 24 adet nirengi tesisi kurulmuştur. Oluşturulan ağda 2018-2019 yıllarında 3 periyot GNSS ölçüsü yapılmış ve elde edilen sonuçlar GAMIT/GLOBK yazılım takımı ile değerlendirilerek bölgenin güncel hız haritası elde edilmiştir. Yapılan çalışmada, Tuz Gölü Fay Zonu Güney kesiminde Avrasya referans sistemi sabit olmak üzere yıllık 10 ile 35 mm arasında batı ve kuzey batı yönünde bir hareket belirlenmiştir. Noktalara ait standart sapma değerleri 2-6 mm arasında değişmektedir. İlerleyen yıllarda yapılan yeni kampanya ölçüleri ile birlikte standart sapma değerlerinin azalacağı düşünülmektedir.Öğe Use of EO-1 Advanced Land Imager (ALI) multispectral image data and real-time field sampling for water quality mapping in the HirfanlA +/- Dam Lake, Turkey(SPRINGER HEIDELBERG, 2013) Kavurmacı, Murat; Ekercin, Semih; Altaş, Levent; Kurmaç, YakupThis paper focuses on the evaluation of water quality variations in HirfanlA +/- Water Reservoir, which is one of the most important water resources in Turkey, through EO-1 (Earth Observing-1) Advanced Land Imager (ALI) multispectral data and real-time field sampling. The study was materialized in 20 different sampling points during the overpass of the EO-1 ALI sensor over the study area. A multi-linear regression technique was used to explore the relationships between radiometrically corrected EO-1 ALI image data and water quality parameters: chlorophyll a, turbidity, and suspended solids. The retrieved and verified results show that the measured and estimated values of water quality parameters are in good agreement (R (2) > 0.93). The resulting thematic maps derived from EO-1 multispectral data for chlorophyll a, turbidity, and suspended solids show the spatial distribution of the water quality parameters. The results indicate that the reservoir has average nutrient values. Furthermore, chlorophyll a, turbidity, and suspended solids values increased at the upstream reservoir and shallow coast of the HirfanlA +/- Water Reservoir.Öğe Use of Landsat land surface temperature and vegetation indices for monitoring drought in the Salt Lake Basin Area, Turkey(Hindawi Publishing Corporation, 2014) Orhan, Osman; Ekercin, Semih; Dadaşer Çelik, FilizThe main purpose of this paper is to investigate multitemporal land surface temperature (LST) changes by using satellite remote sensing data. The study included a real-time field work performed during the overpass of Landsat-5 satellite on 21/08/2011 over Salt Lake, Turkey. Normalized vegetation index (NDVI), vegetation condition index (VCI), and temperature vegetation index (TVX) were used for evaluating drought impact over the region between 1984 and 2011. In the image processing step, geometric and radiometric correction procedures were conducted to make satellite remote sensing data comparable with in situ measurements carried out using thermal infrared thermometer supported by hand-held GPS. The results showed that real-time ground and satellite remote sensing data were in good agreement with correlation coefficient (R-2) values of 0.90. The remotely sensed and treated satellite images and resulting thematic indices maps showed that dramatic land surface temperature changes occurred (about 2 degrees C) in the Salt Lake Basin area during the 28-year period (1984-2011). Analysis of air temperature data also showed increases at a rate of 1.5-2 degrees C during the same period. Intensification of irrigated agriculture particularly in the southern basin was also detected. The use of water supplies, especially groundwater, should be controlled considering particularly summer drought impacts on the basin.Öğe Water quality retrievals from high resolution ikonos multispectral imagery: a case study in İstanbul, Turkey(Springer Nature, 2007) Ekercin, SemihThis paper presents an application of high resolution satellite remote sensing data for mapping water quality in the Goldon Horn, Istanbul. It is an applied research emphasizing the present water quality conditions in this region for water quality parameters; secchi disc depth (SDD), chlorophyl-a (chl-a) and total suspended sediment (TSS) concentration. The study also examines the retrievals of these parameters through high resolution IKONOS multispectral data supported by in situ measurements. Image processing procedure involving radiometric correction is carried out for conversion from digital numbers (DNs) to spectral radiance to correlate water quality parameters and satellite data by using multiple regression technique. The retrieved and verified results show that the measured and estimated values of water quality parameters in good agreement (R 2?>?0.97). The spatial distribution maps are developed by using multiple regression algorithm belonging to water quality parameters. These maps present apparent spatial variations of selected parameters and inform the decision makers of water quality variations in a large water region in the Istanbul metropolitan area.
