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Chlorophyll pigment concentration and sea surface temperature of the black sea
(Gültekin Özdemir, 2018) Kavak, Mehmet Tahir
As an enclosed sea, the Black Sea has countless economic activities (mainly tanker traffic and fisheries) and recreational activities, with the consequence of being threatened by dramatic dangers and pollution. Optical remote sensing can provide a novel look at physical processes and then driving mechanisms. It is worthwhile to know how the temperature and other marine parameters change on seasonal and long-term scales. In the paper CZCS (Coastal Zone Color Scanner) and AVHRR (Advanced Very High Resolution Radiometer) satellite were used to study the relationship between photosynthesis and SST since phytoplankton forms the very lowest clement in the marine ecosystem. Satellite derived data could provide information on the amount of sea life present in any given area throughout the world. The information could also be useful in connection with studies of global changes m temperature and what effect they could have on the total abundance of marine life. Present work which used CD-ROM set from NASAdid not found evidence of correlation between chlorophyll pigment concentration and SST of the Black Sea with 99.95% certainty, three channel algorithm or the use of fluorescence or chlorophyll absorption peak in the red suggested for future work.
Cloud cover investigatıon of East Mediterranean Sea
(Elsevier, 2014) Kavak, Mehmet Tahir; Yıldırım, Ahmet; Karadoğan, Sabri
One important of satellite remote sensing is the count of cloudy days of a particular region. Cloud cover hampers radiation received from the sun therefore controls LST (land surface, SST (Sea Surface Temperature) accordingly humidity, evaporation, agriculture, tourism, and other human activities. Present work investigated long term high resolution cloud cover of the Eastern Mediterranean Sea using 6927 daily composite AVHRR satellite data from March 1993 to December 2012. Results mapped potential availability of obtaining cloud free images for use of other disciplines.
Formation of collapse doline lakes in the Diyarbakir basın: Morphological features, dynamics and geoarchaeological significance
(Kuvaterner Araştırma Grubu (Quaternary Research Group – KAG) Ankara Üniversitesi (Ankara University – AU), 2014) Karadoğan, Sabri; Kuzucuoğlu, Catherine; Kavak, Mehmet Tahir
The Upper Tigris Basin (SE Turkey) is a Tertiary subsidence basin between the edge of the Southeast Taurus and the Mardin Plateau. In this region, some very interesting landforms are caused by geomorphological processes affecting Tertiary-aged gypsum karst. These are collapse dolines related at places to tectonic fractures of faults, widely occurring east of Bismil city, especially along streams some of these structures contain deep or shallow lakes contrasting with the surrounding very dry environment. Several types of dolines are encountered: - The majority is circular; a few exhibit an almond-like form. - Some dolines contain lakes fed by more or less abundant underground water with the possible addition of a rill eroding the plateau above. Lakes in these karstic structures always occur because an impermeable clay layer resulting from gypsum alteration covers the bottom of the depression. - Some (rare) collapse dolines are deep and encircled by cliffs, but the majority consists of shallow depressions at different stages of evolution. Most of the deep dolines are distributed along a lineament north of the Tigris valley corresponding to a probable fault line. The shallowest dolines often contain (but not always) shallow lakes impacted by the drainage of irrigated fields. If, in the past, the oldest dolines contained permanent lakes fed by precipitation (+ runoff in some cases) and precipitation-responding underground water, (a) the lake levels must have varied according to their sensitivity to humidity (precipitation), vegetation cover and evaporation; (b) lake sediments may record past climatic variations. Besides, these lakes providing a water resource for human and animal needs, it is not surprising that Neolithic and Chalcolithic sites are found close to some dolines.
Hevsel Bahçelerinin NDVI değerlerinin uzaktan algılama teknikleri kullanarak uzun dönem için incelenmesi
(Institut Français D’études Anatoliennes (IFEA), 2015) Kavak, Mehmet Tahir; Karadoğan, Sabri; Özdemir, Gültekin; Assénat, Martine
Kentin güneyinde nehrin en geniş menderesli akışını yaptığı kesimde killi depoların daha kolay ve çabuk aşındırılmasından dolayı vadi oldukça genişlemiş ve Hevsel bahçeleri adı verilen genç alüvyal dolgu malzemeli menderes yeniği taraçalarının oluşumuna neden olmuştur. Kentten deşarj edilen atık suyun ve bazalt akiferden boşalan sularla sulanan bu bahçelerin hem kentli nüfusun uzun yıllar sebze ve meyve ihtiyacının karşılanmasındaki önemi hem de görsel ve rekreatif açıdan bir doğal peyzaj alanı olarak rolü büyüktür. Nitekim söz konusu alan değişik çevrelerce farklı kullanım amaçları doğrultusunda sıkça gündeme gelmekte ve ciddi değişikliklere uğramaktadır.
Investigating vineyard areas of Eğil county of Diyarbakır using remote sensing and GIS techniques
(T.C. Tarım ve Orman Bakanlığı, 2014) Kavak, Mehmet Tahir; Karadoğan, Sabri; Özdemir, Gültekin
Dünya’nın bağcılık için en uygun ekolojik koşullarına sahip olan ülkemizde, Diyarbakır ili yaklaşık 22 500 ha üzüm üretim alanı ile iller sıralamasında sekizinci, 123 000 ton üzüm üretimi ile ise dokuzuncu sırada yer almaktadır. Ekonomisi büyük ölçüde tarıma dayalı olan ve kuru tarımın yaygın olduğu Diyarbakir ilinde, tahıllardan sonra bağcılık en önemli tarım kollarından birisi durumundadır. Bu çalışmada Diyarbakır’ın Eğil ilçesinde üzüm yetiştirilen alanların uzaktan algılama ve coğrafi bilgi sistemleri kullanılarak belirlenmesi amaçlanmıştır. Çalışmada Landsat-TM (Thematic Mapper), Landsat-ETM+ (Enhanced Thematic Mapper plus) uydularının üzüm vejetasyonunun en yoğun olduğu Mart ve Kasım ayları arasındaki görüntülerinden faydalanılmıştır. Ayrıca 1/25000 ve 1/100000 ölçekli topoğrafya haritalarından ve arazide koordinat ölçümleri için GPS cihazından yararlanılmıştır. Öncelikle uydu görüntüsü üzerinde ilçe sınırları çizilmiş, daha sonra seçilen bant desenine bağlı olarak bitki örtüsü ve özellikle üzüm yetiştirilen alanlar tespit edilmiştir. Bilgisayar ortamında, Ermapper ve Pancroma yazılımları yardımıyla üretilen bulgu ve analizler arazi çalışmaları ile birlikte yürütülerek elde edilen veriler karşılaştırılmıştır
Investigation of chlorophyll pigment concentration and sea surface temperature of the Lake Van
(IEDSR Association, 2020) Kavak, Mehmet Tahir; Karadoğan, Sabri; Malıt, Veysel
Current study is investigated chlorophyll-a (Chl-a) pigment concentration and its relationship with Sea Surface Temperature (SST) using cloud-free high resolution 59 Landsat-The Operational Land Imager (OLI) images from May 2013 to September 2018 covering Lake Van of Turkey. In addition, the concentrations of coccolithophore which is a kind of phytoplankton was also studied using the same method. The fact that Van Lake is extremely rich in terms of aquatic life has led to the investigation of the factors affecting the marine habitat. Therefore, SST, Chl-a concentrations, as well as the relationship between them and coccolithophore concentrations were investigated to evaluate marine life and ecosystem in the Lake. Satellite-generated data can provide information about the marine life in a particular area worldwide. Coccolithophore, SST and Chl-a were obtained from high resolution 59 Landsat OLI using SeaDAS software. Aforementioned parameters were extracted from images using SeaDAS's OCSSW L2GEN module and then output processed by QGIS (Open Source Geographic Information System) to conduct statistical calculation. Negative correlation coefficients of 74% and 73.7% were found for 2014 and 2017, respectively, and these were not statistically significant. Although the information does not give meaningful results, it may be useful in future studies about the effects of global temperature changes and the marine life for particular region
Investigation the effects of land cover factors on climate in Diyarbakir using remote sensing techniques
(Çanakkale Onsekiz Mart University, 2017) Kavak, Mehmet Tahir; Karadoğan, Sabri
The relationship between vegetation and Land Surface Temperature (LST) using AVHRR (Advanced Very High Resolution Radiometer) for 17 years (1998-2014), NDVI for 20 years (1994-2014) over 94 % and cloud cover for 15 years of Diyarbakir are presented. It is found that the correlations between LST and Normalized Difference Vegetation Index (NDVI) depend on the season-of-year. For winter, the correlation between NDVI and LST is positive. Correlations between LST and NDVI decreased during the warm seasons. Thus temperature-related drought indices may only be used in the warm seasons from June to October, and should be used with caution during cold seasons in Diyarbakır. Since vegetation is high on April and May both month was also studied.
Long term cloud cover and SST investigation of Mediterranean, Adriatic and Aegean seas
(International Engineering, Science & Education Group, 2016) Kavak, Mehmet Tahir; Karayücel, Sedat; Karadoğan, Sabri; Yılmaz, Musa; Akkılıç, Kemal; Gümüş, Bilal; Gümüş, Rojan; Asker, Mehmet Emin; Kılıç, Hibetullah
One important of satellite remote sensing is the count of cloudy days of a particular region. Cloud cover hampers radiation received from the sun therefore controls Land Surface Temperature (LST), Sea Surface Temperature (SST) accordingly humidity, evaporation, agriculture, aquaculture, tourism, and other human activities. Present work investigated long term cloud cover and SST of the Mediterranean Sea (MS) using high resolution 6927 daily 206 monthly composite Advanced Very High resolution Radiometer (AVHRR) satellite data from March 1993 to December 2012. The results could give a clue for regional and global climate change to take an action for the feature. The results were discussed as well as the geographical planetary factors that determine the climate of the Mediterranean basin and in the context of global climate change. The results obtained also for other disciplines (climate, meteorology, Oceanography to, Hydrography, Biology, Environmental Science, Agriculture, Aquaculture, Tourism, such as Industry) will create a data source. SST patterns also revealed oceanographic events which was studied in earlier work too.
Long term cloud cover and SST investigation of the Black Sea
(International Engineering, Science & Education Group, 2016) Kavak, Mehmet Tahir; Karadoğan, Sabri; Karayücel, Sedat; Yılmaz, Musa; Akkılıç, Kemal; Gümüş, Bilal; Gümüş, Rojan; Asker, Mehmet Emin; Kılıç, Hibetullah
One important of satellite remote sensing is the count of cloudy days of a particular region. Cloud cover hampers radiation received from the sun therefore controls LST (land surface, SST (Sea Surface Temperature) accordingly humidity, evaporation, agriculture, aquaculture, tourism, and other human activities. Present work investigated long term cloud cover of the Black Sea using high resolution 6927 daily and 207 monthly composite AVHRR satellite data from March 1993 to December 2012. The results could give a clue for regional and global climate change to take an action for the feature. Results mapped potential availability of obtaining cloud free images for use of other disciplines. The results were discussed as well as the geographical planetary factors that determine the climate of the Black Sea basin and in the context of global climate change. The results obtained also for other disciplines (climate, meteorology, oceanography, hydrography, biology, environmental science, agriculture, tourism, such as Industry) will create a data source. SST patterns also revealed oceanographic events which was studied in earlier work too.
LONG TERM CLOUD COVER AND SST INVESTIGATION OF THE BLACK SEA
(Bilal GÜMÜŞ, 2016) Kavak, Mehmet Tahir; Karadoğan, Sabri; Karayücel, Sedat
One important of satellite remote sensing is the count of cloudy days of a particular region. Cloud cover hampers radiation received from the sun therefore controls LST (land surface, SST (Sea Surface Temperature) accordingly humidity, evaporation, agriculture, aquaculture, tourism, and other human activities. Present work investigated long term cloud cover of the Black Sea using high resolution 6927 daily and 207 monthly composite AVHRR satellite data from March 1993 to December 2012. The results could give a clue for regional and global climate change to take an action for the feature. Results mapped potential availability of obtaining cloud free images for use of other disciplines. The results were discussed as well as the geographical planetary factors that determine the climate of the Black Sea basin and in the context of global climate change. The results obtained also for other disciplines (climate, meteorology, oceanography, hydrography, biology, environmental science, agriculture, tourism, such as Industry) will create a data source. SST patterns also revealed oceanographic events which was studied in earlier work too.
Long Term Investigation of SST Regime Variability and Its Relationship with Phytoplankton in the Caspian Sea Using Remotely Sensed AVHRR and SeaWiFS Data
(Central Fisheries Research Inst, 2012) Kavak, Mehmet Tahir
Long term Sea Surface Temperature variability and its relation with, chlorophyll (chl) pigment of phytoplankton biomass were investigated using SeaWiFS (Sea-viewing Wide Field of-view Sensor) and AVHRR (Advanced Very High Resolution Radiometer) satellite imagery. SST acquired from AVHRR (1985 to 2009) showed seasonal, annual and inter-annual variability of temperature. Monthly variability chl from SeaWiFS 1985 to 2009 has also been investigated, Correlation between SST and chl was found to be 78% and significant at P<0.05.
Long term investigation of SST regime variability and Its relationship with phytoplankton in the caspian Sea using remotely sensed AVHRR and SeaWiFS data
(2012) Kavak, Mehmet Tahir
Bu çalışmada Hazar Denizinin 24 yıllık, mevsimsel su yüzeyi sıcaklığı ve bu sıcaklığın fitoplanktonla ilişkisi AVHRR (Çok Yüksek Çözümlemeli Radyometre) ve SeaWiFS (Sea-viewing Wide Field of-view Sensor) uydu verileri kullanılarak incelenmiştir. Çalışmanın en önemli sonucu fitoplankton ile su yüzeyi sıcaklığını %78 oranında korelasyon göstermesidir (P<0,05).
Long time SST and Chlorophyll-a pigment concentration of Lake Van using MODIS
(2021) Kavak, Mehmet Tahir
Current work concentrated on long-time SST and Chlorophyll-a pigment concentration of Lake Van using ModisAqua acquired data. Investigating the relationship between sea surface temperature (SST) and chlorophyll-a (Chl-a)increases our understanding of marine ecosystem and also provide us to assess the effect on aquatic animals that mayarise as a result of changes in the environment. Long term Sea Surface Temperature variability and its relationship withchlorophyll-a pigment of phytoplankton biomass were investigated by using MODIS-Aqua (Moderate ResolutionImaging Spectroradiometer) satellite imagery. SST and Chl-a acquired from MODIS-Aqua showed seasonal, annualand interannual variability of temperature. Monthly variability Chl-a from MODIS 2002 to 2020 also investigated,significant correlation between SST and Chl-a was not found P<0.05. First PCA of SST seems to show generalaverage pattern of the lake, on the other hand PCA’s of Chl-a could not be calculated due to lack of null pixels within images.
Marmara Denizinde Su Yüzeyi Sıcaklığı İle Tektonik Aktivite İlişkisinin Uzaktan Algılama Metoduyla Karşılaştırılması
(Afyon Kocatepe Üniversitesi, 2010) Karadoğan, Sabri; Kavak, Mehmet Tahir; Yıldırım, Ahmet
Atmosferik ve jeolojik doğa olayları değişiminin ve ortaya konması açısından SST (Sea-Surface Temperature) büyük önem taşımaktadır. SST (Sea-Surface Temperature) Deniz Yüzeyi Sıcaklığı hava ve deniz yüzeyleri arasındaki ısı değişiminin tahmin edilmesinde kullanılan önemli bir jeofiziksel parametredir. Bu parametrenin deprem gibi tektonik aktivitelerle ilişkisi de araştırılmaktadır. Türkiye 17 Ağustos 1998’de büyük bir deprem yaşamıştır. Odak noktası Marmara denizinin batısındaki İzmit körfezi olan depremin USGS kayıtlarına göre yüzey dalgası magnitüdü 7,8 dir. Bu depremden sonra Marmara Denizi ve Kuzey Anadolu Fayı çokça tartışılmaya başlandı. Marmara denizine ilişkin birçok araştırma yapıldı. Bu çalışmada büyük deprem öncesine ve sonrasına ait uzun yılların depremin meydana geldiği ay içindeki AVHHR uydu verileri kullanılarak uzaktan algılama yöntemiyle deniz yüzeyindeki su sıcaklık koşullarının değişimi araştırılmıştır.
NDVI ve DEM verileriyle bitki örtüsünün yatay, dikey ve zamansal değişiminin incelenmesi: Savur ilçesi (Mardin) örneği
(Dicle Üniversitesi Fen Bilimleri Enstitüsü, 2023) Karadoğan, Sabri; Kavak, Mehmet Tahir; Al, Aladdin
Uzaktan Algılama ile Coğrafi Bilgi Sistemleri teknikleri yeryüzünün doğal özelliklerini, yer ve zamana göre değişiminin gözlemlenmesinde kullanılan yaygın ve güvenilir yöntemlerdendir. Bu yöntemlerin birlikte kullanıldığı en yaygın uygulamalardan biri NDVI (Normalize Edilmiş Fark Bitki Örtüsü İndeksi) analizleridir. NDVI analizi genellikle kuraklığı izlemek, tarımsal verimliliği tahmin etmek veya bölgelere göre bitki örtüsündeki tahribatı belirlemek için yapılan çalışmalarda kullanılır. Böylece doğal döngü açısından önemli bir yere sahip olan bitkilerin ve bitki örtüsünün artış ve azalışının denetlenmesi ve izlenmesi mümkün olabilmektedir. Bu çalışmada, Mardin ili Savur ilçe sınırları içindeki alanı kapsayan 1995-2021 yılları arasındaki 30 m çözünürlüklü Landsat 5, Landsat 8 ve 2000-2021 yılları arasındaki 500 metre çözünürlüklü MODIS (Moderate Resolution Imaging Spectroradiometer) uydu görüntülerinden yararlanılarak NDVI ve DEM (Sayısal Yükselti Modeli) veri katmanları ile sahanın bitki örtüsünün yatay ve dikey yönde dağılımının ve değişiminin belirlenmesi amaçlanmıştır. Bulgular harita ve diyagramlarla değerlendirilmiştir.
The relationship between sea surface temperature and chlorophyll concentration of phytoplanktons in the Black Sea using remote sensing techniques
(Triveni Enterprises, 2012) Kavak, Mehmet Tahir; Karadoğan, Sabri
Present work investigated the relationship between Chlorophyll (Chl), of phytoplankton biomass, and sea surface temperature (SST) of the Black Sea, using Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and Advanced Very High Resolution Radiometer (AVHRR) satellite imagery. Satellite derived data could provide information on the amount of sea life present (Brown algae, called kelp, proliferate, supporting new species of sea life, including otters, fish, and various invertebrates) in a given area throughout the world. SST from AVHRR from 1993 to 2008 showed seasonal, annual and interannual variability of temperature, monthly variability Chi from SeaWiFS from 1997 to 2009 has also been investigated. Chi showed two high peaks for the year 1999 and 2008. The correlation between SST and Chl for the same time has been found to be 60%. Correlation was significant at p<0.05. The information could also be useful in connection with studies of global changes in temperature and what effect they could have on the total abundance of marine life.
Study of weekly cloud cover over the Black Sea
(Mehmet Akif Ersoy Üniversitesi, 2016) Kavak, Mehmet Tahir; Karadoğan, Sabri; Efe, Recep; Cürebal, İsa
Present work investigated long term weekly cloud cover of the Black Sea using AVHRR satellite data from March 1993 to December 2014. It was found that in general, the possibility of compositing a 100% cloud free image of the whole Black Sea for a single day is quite low. This work also suggested that the 20th to the 41st weeks of the year are optimal weeks for a sunshine holiday in resorts such as Istanbul, Samsun, Sinop and Zonguldak in Turkey.
Surface water temperature of Salt Lake determined through remote sensing method and AVHRR satellite data
(Journal of Balkan Ecology, 2009) Kavak, Mehmet Tahir; Karadoğan, Sabri; Yıldırım, Ahmet
The paper deals with the surface water temperature (SWT), which is one of the main ecological factors exerting influ- ence on atmosphere temperature and heat balance in the Salt lake region in Turkey. We applied the remote sensing method and satellite data. We established the monthly (minimum, maximum and average) mean surface water temperatures for the 1993-2008 period. Multi- year comparison shows a trend to surface* water temperature decrease for the period considered. We found the regression equa- tion of this trend. One of the main reasons explaining the trend is the reduction of depth and volume of the Salt lake and the decrease of its energy storage capacity.
Tectonic activities of Marmara Sea and their influance on surface water temperature
(Journal of Balkan Ecology, 2012) Kavak, Mehmet Tahir; Karadoğan, Sabri
The paper deals with sea surface water temperature (SST), which is a factor exerting influence on the atmospheric and geologic phenomena. It is necessary to pre- dict the heat exchange between atmosphere and sea water. The dependence of this factor on the tectonic activities such as earthquake is considered for using it in early warning system. We measured the long time variation of SST before and after the earthquake. On 17 August 1999, Turkey has exposed to strong earthquake (7.8 by the Richter sca- le) with center in the gulf of Izmit at the west of Marmara sea.
Uzaktan algılama yöntemleri kullanılarak Diyarbakır kenti civarında Dicle Nehri Vadisinde (Hevsel Bahçeleri) arazi örtüsündeki değişimin incelenmesi
(T.C. Tarım ve Orman Bakanlığı, 2014) Şenyiğit, Sülem; Yücelen, Aziz Mahmut; Kavak, Mehmet Tahir; Özdemir, Gültekin; Karadoğan, Sabri
Diyarbakır kentinin kuruluş yerinde etkili olan en önemli unsurlardan biri Dicle Nehri’dir. Dicle Nehri Diyarbakır kenti civarında gömük menderesli akarsu özelliği gösterir. Nehir yer yer örgülü ve çizgisel akış karakteri göstermekle birlikte vadi tabanında çoğunlukla menderes kuşakları oluşturmakta ve taşkın yataklarına (Feyezan ovası) özgü jeomorfolojik aşınım ve birikim yapıları ortaya çıkmaktadır. Kentin güneyinde nehrin en geniş menderesli akışını yaptığı kesimde killi depoların daha kolay ve çabuk aşındırılmasından dolayı vadi oldukça genişlemiş ve Hevsel bahçeleri adı verilen genç alüvyal dolgu malzemeli menderes yeniği taraçalarının oluşumuna neden olmuştur. Kentten deşarj edilen atık suyun ve bazalt akiferden boşalan sularla sulanan bu bahçelerin hem kentli nüfusun uzun yıllar sebze ve meyve ihtiyacının karşılanmasındaki önemi hem de görsel ve rekreatif açıdan bir doğal peyzaj alanı olarak rolü büyüktür. Ancak Dicle vadisindeki, özellikle Hevsel bahçelerindeki Hassas ve dinamik jeomorfolojik koşullar aynı zamanda hassas olan ekosistemini bünyesinde barındırmaktadır. Zira akarsuların çok sık fluviyal ve topoğrafik rejim değişikliği gösterdiği bu gibi alanlar, üstelik yanı başında yoğun bir kentli nüfusu barındırıyorsa jeomorfolojikekolojik ve hem de arazi kullanımı ilkeleri açısından oldukça hassas bölgeler oldukları unutulmamalıdır. Bu nedenle arazi kullanım biçimi ve doğal bir parametre olarak arazi örtüsü gelişimi dikkatle izlenmelidir. Nitekim söz konusu alan değişik çevrelerce farklı kullanım amaçları doğrultusunda sıkça gündeme gelmekte ve ciddi değişikliklere uğramaktadır. Bu çalışmada son yıllarda arazi örtüsü üzerindeki değişimleri incelemek amacıyla sıklıkla kullanılan uzaktan algılama yöntemleri ve 2000, 2005, 2010, 2014 yılına ait Landsat ait uydu görüntüleri kullanılarak Diyarbakır kenti civarında Dicle vadisinde, özellikle Hevsel bahçelerindeki değişim tespit edilmiştir. Bu amaçla Landsat uydu görüntüleri üzerine çeşitli değişim teknikleri uygulanmış ve sonuçlar haritalanarak özellikle yeşil alan kaybı belirlenmeye çalışılmıştır.

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