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Üniversite öğrencilerinin biyoçeşitlilik algısı ve biyoçeşitlilikle ilgili tutumlarının analizi
Turkey has a very rich biodiversity yet this enourmous richness is seriously under threat. Lack of nature education leads conservation acts and campaigns to be under supported and even rejected by people. To have a sufficient nature education is very important for young population, who are scientists, engineers, decision makers, law makers...etc. of the future. In Turkey, nature education basically consists of biology courses. In this study, two hundred higher education students were asked to participate in a twelve item questionnaire about biodiversity. Their perception and attitudes towards biodiversity were investigated. Results show that although the students know what biodiversity is and they are sensitive about environmental issues they have many confusions, misconceptions and lack of knowledge. Results also underline that, a well planned, early starting nature education which families also will be a part of it is required and this education should be seperated from biology courses and be a life long learning process.
Bir Zebra Midyesi (Dreissena Polymorpha) istilasının mekansal ve zamansal örüntüleri
Biological invasions are an important dimension of global change and is an environmental problem which has a serious consequences. Awareness about this issue has increased, especially after the invasion of zebra mussels in Great Lakes of North America and environmental and economic results of this invasion. In this study, spatial and temporal patterns of the zebra mussel invasion in Great Lakes was studied, for a 20-year period by using individual based modelling method. The model was developed in NetLogo environment. Numerical experiments were also conducted in this environment. First of six experiment sets is reference case experiment. Effects of phytoplankton density on zebra mussel populations were investigated in P75 and P125 experiment sets. In T0.1 and T10 experiment sets, effects of transportation probability on zebra mussels were investigated. Last experiment set, SupD, was conducted to observe how environmental changes would affect a biological invasion, by applying Lake Huron conditions to Lake Superior. According to results, there is no linear relation between the change of phytoplankton amount and the increase of zebra mussel population and slight changes of phytoplankton amount cause significant increases in invasion strenght. Changes in transportation probability, affect invasion stages temporally and also have impact on population size. SupD experiment results show that probable climate changes have a strengthening effect on biological invasions. Results also show that, lake location in the waterbody network is also important beside the individual conditions of each lake and mussel populations constitute characteristic patterns depending on invasion strenght.
Hersiniyen Orojenik Sisteminin Doğu Avrupadaki Kısmının Geometrisi, Evrimi ve İskititlere Geçişi
The Hercynian Orogen, one of the best-known orogenic belts in the world, still hides many secrets concerning its evolution. This orogen formed through the collision between Laurussia and Gondwana-Land, which resulted in the supercontinent of Pangaea. Pangaea's formation began in the late Devonian with the onset of subduction and continued from the early-medial Carboniferous to the Permo-Triassic by means of collision. However, at the eastern part of this supercontinent, collision never happened and subduction continued in the Permo-Triassic. The coast of the Palaeo-Tethys known as Alpine-type Triassic succession was the scene of high mobility events in the core of the Pangaea in terms of Hercynian and Post-Hercynian stages. It is a fact that when the subduction process was still continuing, a rifting event began in the Permo Triassic at the eastern part of Pangaea by disrupting a magmatic arc. The results show a continuous arc goes from the Rhodope-Pontide Fragment in the north, through the Eastern Carpathians, Tisza Block, Western Carpathians, and Pelagonian Zone, to the Eastern Pontides in the south. Additionally, the lithostratigraphic charts of all the tectonic zones indicate the volcano sedimentary complexes, which show a rifting event as their most likely interpretation. As a consequence of this rifting, a marginal basin started to form beginning from the eastern part and tore westward by tracing the weak zones of the former arc. It began to take shape from the Karakaya Complex, goes through the Pelagonian zone and the Inner Western Carpathians namely Meliaticum into the Tisza Block in the Late Permian-Early Triassic. From the medial to the end of the late Triassic, the entire Hellenic-Dinaric System and Italy began to disintegrate, which started from the Pindos Zone in Hellenides and Sicily in Italy, and joined together into the Southern Alps by passing through all along the coast of the present Adriatic Sea. This presentation shows a reconstruction of the Mediterranean Tethysides at the time of the early Triassic. It was done by palinspastically restoring all the orogenic deformation for which data were to be had painstakingly and not just schematically. It is still incomplete, because it does not show the rift areas of the Sclafani-Imerese, Lagonegro and Pindos-Budva, except to show where they were. It also delineates the lie of the Karakaya and the Meliata rifts and shows that they were one and the same rift. Karakaya was later partly incorporated into the Vardar Ocean. Most of it closed during the earliest Jurassic, whereas the Meliata part was delayed until the late Jurassic. These closures are responses to two events: 1) Palaeo-Tethyan closure in case of Karakaya and 2) the opening of the South Atlantic in case of the Meliata. This paper addresses itself mainly to the solution of the Karakaya-Meliata problem.
Lavrasya'nın güney aktif kenarı boyunca çarpışma öcesi eklemlenme ve yüzeylenme, Orta Pontidler, Türkiye
The Central Pontides is an accretionary-type orogenic area within the Alpine-Himalayan orogenic belt characterized by pre-collisional tectonic continental growth. The region comprises Mesozoic subduction-accretionary complexes and an accreted intra-oceanic arc that are sandwiched between the Laurasian active continental margin and Gondwana-derived the Kırşehir Block. The subduction-accretion complexes mainly consist of an Albian-Turonian accretionary wedge representing the Laurasian active continental margin. To the north, the wedge consists of slate/phyllite and metasandstone intercalation with recrystallized limestone, Na-amphibole-bearing metabasite (PT= 7–12 kbar and 400 ± 70 ºC) and tectonic slices of serpentinite representing accreted distal part of a large Lower Cretaceous submarine turbidite fan deposited on the Laurasian active continental margin that was subsequently accreted and metamorphosed. Raman spectra of carbonaceous material (RSCM) of the metapelitic rocks revealed that the metaflysch sequence consists of metamorphic packets with distinct peak metamorphic temperatures. The majority of the metapelites are low-temperature (ca. 330 °C) slates characterized by lack of differentiation of the graphite (G) and D2 defect bands. They possibly represent offscraped distal turbidites along the toe of the Albian accretionary wedge. The rest are phyllites that are characterized by slightly pronounced G band with D2 defect band occurring on its shoulder. Peak metamorphic temperatures of these phyllites are constrained to 370-385 °C. The phyllites are associated with a strip of incipient blueschist facies metabasites which are found as slivers within the offscraped distal turbidites. They possibly represent underplated continental metasediments together with oceanic crustal basalt along the basal décollement. Tectonic emplacement of the underplated rocks into the offscraped distal turbidites was possibly achieved by out-of-sequence thrusting causing tectonic thickening and uplift of the wedge. 40Ar/39Ar phengite ages from the phyllites are ca. 100 Ma, indicating Albian subduction and regional HP metamorphism. The accreted continental metasediments are underlain by HP/LT metamorphic rocks of oceanic origin along an extensional shear zone. The oceanic metamorphic sequence mainly comprises tectonically thickened deep-seated eclogite to blueschist facies metabasites and micaschists. In the studied area, metabasites are epidote-blueschists locally with garnet (PT= 17 ± 1 kbar and 500 ± 40 °C). Lawsonite-blueschists are exposed as blocks along the extensional shear zone (PT= 14 ± 2 kbar and 370–440 °C). They are possibly associated with low shear stress regime of the initial stage of convergence. Close to the shear zone, the footwall micaschists consist of quartz, phengite, paragonite, chlorite, rutile with syn-kinematic albite porphyroblast formed by pervasive shearing during exhumation. These types of micaschists are tourmaline-bearing and their retrograde nature suggests high-fluid flux along shear zones. Peak metamorphic mineral assemblages are partly preserved in the chloritoid-micaschist farther away from the shear zone representing the zero strain domains during exhumation. Three peak metamorphic assemblages are identified and their PT conditions are constrained by pseudosections produced by Theriak-Domino and by Raman spectra of carbonaceous material: 1) garnet-chloritoid-glaucophane with lawsonite pseudomorphs (P= 17.5 ± 1 kbar, T: 390-450 °C) 2) chloritoid with glaucophane pseudomorphs (P= 16-18 kbar, T: 475 ± 40 °C) and 3) relatively high-Mg chloritoid (17%) with jadeite pseudomorphs (P= 22-25 kbar; T: 440 ± 30 °C) in addition to phengite, paragonite, quartz, chlorite, rutile and apatite. The last mineral assemblage is interpreted as transformation of the chloritoid + glaucophane assemblage to chloritoid + jadeite paragenesis with increasing pressure. Absence of tourmaline suggests that the chloritoid-micaschist did not interact with B-rich fluids during zero strain exhumation. 40Ar/39Ar phengite age of a pervasively sheared footwall micaschist is constrained to 100.6 ± 1.3 Ma and that of a chloritoid-micaschist is constrained to 91.8 ± 1.8 Ma suggesting exhumation during on-going subduction with a southward younging of the basal accretion and the regional metamorphism. To the south, accretionary wedge consists of blueschist and greenschist facies metabasite, marble and volcanogenic metasediment intercalation. 40Ar/39Ar phengite dating reveals that this part of the wedge is of Middle Jurassic age partly overprinted during the Albian. Emplacement of the Middle Jurassic subduction-accretion complexes is possibly associated with obliquity of the Albian convergence. Peak metamorphic assemblages and PT estimates of the deep-seated oceanic metamorphic sequence suggest tectonic stacking within wedge with different depths of burial. Coupling and exhumation of the distinct metamorphic slices are controlled by decompression of the wedge possibly along a retreating slab. Structurally, decompression of the wedge is evident by an extensional shear zone and the footwall micaschists with syn-kinematic albite porphyroblasts. Post-kinematic garnets with increasing grossular content and pseudomorphing minerals within the chloritoid-micaschists also support decompression model without an extra heating. Thickening of subduction-accretionary complexes is attributed to i) significant amount of clastic sediment supply from the overriding continental domain and ii) deep level basal underplating by propagation of the décollement along a retreating slab. Underplating by basal décollement propagation and subsequent exhumation of the deep-seated subduction-accretion complexes are connected and controlled by slab rollback creating a necessary space for progressive basal accretion along the plate interface and extension of the wedge above for exhumation of the tectonically thickened metamorphic sequences. This might be the most common mechanism of the tectonic thickening and subsequent exhumation of deep-seated HP/LT subduction-accretion complexes. To the south, the Albian-Turonian accretionary wedge structurally overlies a low-grade volcanic arc sequence consisting of low-grade metavolcanic rocks and overlying metasedimentary succession is exposed north of the İzmir-Ankara-Erzincan suture (İAES), separating Laurasia from Gondwana-derived terranes. The metavolcanic rocks mainly consist of basaltic andesite/andesite and mafic cognate xenolith-bearing rhyolite with their pyroclastic equivalents, which are interbedded with recrystallized pelagic limestone and chert. The metavolcanic rocks are stratigraphically overlain by recrystallized micritic limestone with rare volcanogenic metaclastic rocks. Two groups can be identified based on trace and rare earth element characteristics. The first group consists of basaltic andesite/andesite (BA1) and rhyolite with abundant cognate gabbroic xenoliths. It is characterized by relative enrichment of LREE with respect to HREE. The rocks are enriched in fluid mobile LILE, and strongly depleted in Ti and P reflecting fractionation of Fe-Ti oxides and apatite, which are found in the mafic cognate xenoliths. Abundant cognate gabbroic xenoliths and identical trace and rare earth elements compositions suggest that rhyolites and basaltic andesites/andesites (BA1) are cogenetic and felsic rocks were derived from a common mafic parental magma by fractional crystallization and accumulation processes. The second group consists only of basaltic andesites (BA2) with flat REE pattern resembling island arc tholeiites. Although enriched in LILE, this group is not depleted in Ti or P. Geochemistry of the metavolcanic rocks indicates supra-subduction volcanism evidenced by depletion of HFSE and enrichment of LILE. The arc sequence is sandwiched between an Albian-Turonian subduction-accretionary complex representing the Laurasian active margin and an ophiolitic mélange. Absence of continent derived detritus in the arc sequence and its tectonic setting in a wide Cretaceous accretionary complex suggest that the Kösdağ Arc was intra-oceanic. This is in accordance with basaltic andesites (BA2) with island arc tholeiite REE pattern. Zircons from two metarhyolite samples give Late Cretaceous (93.8 ± 1.9 and 94.4 ± 1.9 Ma) U/Pb ages. Low-grade regional metamorphism of the intra-oceanic arc sequence is constrained 69.9 ± 0.4 Ma by 40Ar/39Ar dating on metamorphic muscovite from a metarhyolite indicating that the arc sequence became part of a wide Tethyan Cretaceous accretionary complex by the latest Cretaceous. The youngest 40Ar/39Ar phengite age from the overlying subduction-accretion complexes is 92 Ma confirming southward younging of an accretionary-type orogenic belt. Hence, the arc sequence represents an intra-oceanic paleo-arc that formed above the sinking Tethyan slab and finally accreted to Laurasian active continental margin. Abrupt non-collisional termination of arc volcanism was possibly associated with southward migration of the arc volcanism similar to the Izu-Bonin-Mariana arc system. The intra-oceanic Kösdağ Arc is coeval with the obducted supra-subduction ophiolites in NW Turkey suggesting that it represents part of the presumed but missing incipient intra-oceanic arc associated with the generation of the regional supra-subduction ophiolites. Remnants of a Late Cretaceous intra-oceanic paleo-arc and supra-subduction ophiolites can be traced eastward within the Alp-Himalayan orogenic belt. This reveals that Late Cretaceous intra-oceanic subduction occurred as connected event above the sinking Tethyan slab. It resulted as arc accretion to Laurasian active margin and supra-subduction ophiolite obduction on Gondwana-derived terranes.
Van Gölü'nün geç holosen'deki yüksek çözünürlüklü iklim ve çevresel kayıtları
Doğu Anadolu Yüksek Platosu'nda yer alan Van Gölü, 607 km3 hacmi ve 3,570 km2 lik alanı ile dünyanın en büyük 4. kapalı gölü ve en büyük soda gölüdür. Derinliği 460 m ve su seviyesi deniz seviyesinden 1648 m yükseklikte olan gölün suları, yüksek pH değeri (9.8) ve %24'luk tuzluluk oranına sahiptir. Gölün yıllık lamina (varv) yapılı çökel istifi, bölgede yüksek çözünürlüklü iklim ve çevresel değişimlerin arşivini oluşturmaktadır. Bu tez kapsamında, Van Gölü'nde çökel karotlarında özellikle son 3500 yıldaki iklimsel ve çevresel değişim kayıtları incelenmiştir. Çalışmadan elde edilen iklim kayıtları; Anadolu, Yakın Doğu ve Avrupa'dan elde edilmiş kayıtlarla karşılaştırılarak tartışılmıştır. Tez çalışması, Van Gölü'nün farklı bölgelerinden alınan ve uzunlukları 0.75 ile 1.30 m arasında değişen toplam dört karotta değişik kimyasal ve fiziksel analizler ile yapılmıştır. Çok Sensörlü karot tarayıcısı (Multi Sensor Core Logger, MSCL) ile 5 mm çözünürlükte manyetik duyarlılık, yoğunluk ve porozite ölçümleri yapılmış, µ-XRF karot tarayıcısı ile 0.5 mm çözünürlükle 15 element taranmıştır. Sediment örnekleri 0.5-1 cm aralıklarla örneklenerek toplam inorganik (TIC) ve toplam organik karbon (TOC) analizleri yapılmıştır. 0.5-1 cm aralıkla sediment örnekleri 63 μm elek kullanılarak yıkanıp elenmiş elek-üstü malzemede binoküler mikroskop altında ostrakod tanımları yapılmıştır. En uzun çökel karotu boyunca sürekliliği olan ostrakod çeşidi ve sayıları belirlenerek kavkıları toplanmış ve kavkı ve çökel örneklerinin toplam (bulk) karbonat fraksiyonunda duraylı oksijen ve karbon analizleri yapılmıştır. Ayrıca karotun çökel örneklerinin organik madde fraksiyonunda elementel C ve N analizleri yapılmıştır. Van Gölü sediment karotlarının kronostratigrafisi için değişik yöntemler kullanılmıştır. Kronostratigrafinin ana yöntemleri 210Pb radyoizotopik tarihlendirme ve varve sayımı olmakla birlikte; bu iki yönteme ek olarak 137Cs tarihlendirme ve tefrakronoloji yöntemleri de kullanılmıştır. Ayrıca, yüksek TOC değerleri içeren seviyelerde organik karbondan elde edilen AMS radyokarbon yaşları, varve yaşları ile karşılaştırıldığında gölün 1.2 ile 3.8 bin yıl arasında değişen 14C rezervuar yaşına sahip olduğu saptanmıştır. 210Pb analizleri Sıvı Sintilasyon Sayım Sistemi kullanılarak Çift Enerji Pencere Yöntemi (Double Energetic Window Method) ile gerçekleştirilmiştir. Bu yöntem 210Pb izotopunun 17 keV'lik β enerjisini kullanmaktadır. Yöntemin en büyük avantajı örneklerin alınır alınmaz analiz edilebilmesidir. 210Pb tarihlendirme, 210Pb'un kız radyoizotopu olan 210Po'un 5.30 MeV'deki alfa enerjisinden yararlanılarak da yapılabilmektedir. Ancak bu çalışmada kullanılan yöntemden farklı olarak, çevreden gelen ve sediment örneklerinin içinde olması beklenen 210Po radyoizotoplarının 210Pb radyoizotopları ile dengeye gelmesi için en az 5 yarı ömür (yaklaşık 2 yıl) beklemek gerekmektedir. CRS (Constant Rate of Supply) modeli ile yapılan tarihlendirme sonuçlarına göre Van Gölü'nün sedimanlarının sedimantasyon hızı gölün değişik karotlarında 0.3 ile 0.7 mm.yıl-1 arasında, kütle birikim hızları ise 0.3-0.60 kg.m-2.yıl-1 değerleri arasında değişmektedir. Sedimantasyon ve kütle birikim hızlarındaki bu değişkenlik, gölün değişik noktalarındaki farklı sediment akılarına bağlıdır. Sediment akılarındaki bu farklılıklar, gölün topografyasındaki farklılıklara, göl yatağı litolojisine, farklı bölgelerdeki drenaj özelliklerine ve ayrıca bölgeye göre değişim gösteren antropojenik aktivitelere bağlı olarak açıklanabilmektedir. Bir fizyon ürünü olan 137Cs izotopunun çökel karotları boyunca aktivite dağılımları HpGe Gama Sayım Sistemi ile 671 keV'deki gama enerjisi kullanılarak incelenmiş ve 1950-1963 yıllarındaki nükleer silah denemeleri sonucunda ve 1986 yılında meydana gelen Çernobil Nükleer santral kazası sonucu çevreye yayılan 137Cs radyoizotopunun varlığı tespit edilmiştir. Van Gölü sediment karotlarının yaşlandırılması için kullanılan ana yöntemlerden biri olan varv sayımı, bir algoritma ile yıllık laminalı (varv) yapıdaki karotların sayısal X-ışını radyografi görüntülerinden yapılır. Bu çalışmada kullanılan varv sayım yöntemi ile elde edilen yaş verileri, karotların 7.5 cm lik üst kısımları için (100-150 yıl) radyoizotopik (210Pb ve 137Cs) tarihlendirme yöntemlerinden elde edilen yaş verileri ile büyük bir uyum içerisindedir. Bu uyum göz önüne alınarak karotların yaş-derinlik modelleri varv sayım yöntemi kullanılarak yapılmış ve böylece radyoizotopik yöntem ile 100-150 yıla kadar yaşlandırılabilen çökel karot istifleri uzunluklarına bağlı olarak 3500 yıla kadar yaşlandırılmıştır. Geç Holosen süresince, Van Gölü çökel istifinde karbonatlardaki düşük oksijen-izotop değerleri, kış yağışının (kar) etkisinin bir sonucu olarak değerlendirilmektedir. Dağlara doğru yönelen nemi engelleyen yerel yaz doğulu rüzgarlarının erken oluşması ile meydana gelen "klasik" Akdeniz ikliminin, bölgede artan kış yağışlarının sebebi olduğu düşünülmektedir. Ostrakod sayıları, C/N oranı, duraylı izotop değerleri, TOC-TIC değerleri ve Ti/Ca oranı gibi tüm çoklu belirteç (multi-proxy) verileri değerlendirilerek son 3500 yıldaki soğuk/kurak ve ılık/yağışlı dönemlerin değişimleri incelenmiştir. Tüm bu parametrelerin birlikte değerlendirilmesi sonucu söz konusu zaman aralığında 16 adet ardışık soğuk/kurak ve ılık/yağışlı dönem tespit edilmiş olup, bu dönemlerin uzunluğu 100 yıl ile 350 yıl arasında değişim göstermektedir. Günümüzden önce 3500-3300, 2900-2600, 2400-1800, 1600-1450, 1350-1050, 770-600, 500-350 ve 200-0 yılları arasında soğuk/kurak dönemlerin hakim olduğu öte yandan günümüzden önce 3300-2900, 2600-2400, 2300-2100, 1800-1600, 1400-1350, 1050-770, 600-500 ve 350-200 yılları arasında sıcak/yağışlı dönemlerin hüküm sürdüğü sonucuna varılmıştır. Bu çalışmada elde edilen veriler ışığında Van Gölü iklim kayıtlarının özellikle Kuzey Atlantik iklim sistemi ile uyumluluğunu doğrulayan Roma Ilık Dönemi (RWP), Karanlık Çağ Soğuk Dönemi (DACP), Ortaçağ Ilık Dönemi (MWP) ve Küçük Buz Çağı dönemlerini içeren son 1800 yıllık verilerinin Nar Gölü (Orta Anadolu) çökel ve Sofular Mağarası (Kuzeybatı Anadolu) stalagmit kayıtları ile uyumlu olduğu görülmüştür. Bölgesel ölçekte, Van Gölü kayıtları İran'da bulunan Zeribar ve Mirabad göllerine ait düşük çözünürlüklü sediment ve İsrail'de bulunan Soreq Mağarası kayıtları ile de uyumludur. Van Gölü çökel karotları boyunca elde edilen µ-XRF ağır metal profilleri 1960'lardan bu yana göle olan antropojenik girdileri göstermektedir. Van Gölü bölgesinde son 30-60 yılda Zn, Pb, Ni ve Co metallerinin önemli ölçüde arttığı saptanmıştır. Özellikle karotların üst kısımlarında çok belirgin olarak gözüken Zn ve Pb zenginleşmesi 1960 yıllarında başlayan önemli tarımsal ve endüstriyel kirlenmenin bir göstergesidir. µ-XRF sayım sonuçları göz önünde bulundurularak dört karottaki ağır metal konsantrasyonları karşılaştırıldığında Gölde Van Şehri'nin batısından alınan karotta en yüksek ağır metal değerleri karotun üst kısımlarında görülmüştür. Bu sonuç ağır metallerin ana kaynağının antropojenik kirlenme olduğunu güçlü bir şekilde göstermektedir. Son 60 yılı temsil eden, karotların üst kısımlarındaki metal birikimi Van'ın şehirleşme ve endüstrileşmesinin 1960'dan sonra daha hızlandığını doğrulamaktadır. Bu hızlanma Van Gölü kıyılarının her iki yakasınında kara yolu ulaşımına açılmasının bir sonucudur. 1960'lardan itibaren sulama, hasat gibi tarımsal işlemlerde kullanılan tarım makineleri ve trafikteki araç sayısı artmıştır. Bu da araçlarda kullanılan yakıtın içeriğinde bulunan Pb salınımını artırmıştır. Bu salınım artışının sonuçları çalışılan karotlarda belirgin Pb anomalisinin gözlenmesine neden olmuştur. 2000'li yıllarda kurşunsuz yakıtın kullanılmaya başlamasıyla bu anomali değişerek doğal seviyelere gelmiştir. Öte yandan tarımsal faaliyetlerde kullanılan gübrenin içeriğinde bulunan Zn, direkt olarak ya da nehirler aracılığıyla metal kirliliğine katkıda bulunmuştur. Ayrıca genel olarak yollarda artan trafik metal kirliliğinin önemli sebeplerindendir.
Marmara bölgesindeki atmosferik sirkülasyon paternleri ve yağış üzerine etkileri
The Marmara Region comprises the northwestern end of Anatolia and the southeastern end of the Balkans: two peninsulas separated by Dardaneles and Bosphorus straits, and the Sea of Marmara. Located on two continents, Asia and Europe, this unique area is the most industrialized, agriculturally developed and populated geographical division in Turkey with a population density of up to 2500 people per km2 in Istanbul, averaging 300 people per km2 regionally. Parallel to its economic development, the region continues to draw migration from other regions in Turkey. This leads to an ever increasing demand for water, while threatening the existing water resources in the form of new and uncontrolled building activity over water reservoirs. Thus, amount and variability of precipitation play a key role in the management of limited water supply. Large-scale circulation patterns and synoptic patterns play significant role in determining the precipitation climate of the region. For the first time, in order to reveal the synoptic properties of the Marmara, circulation types, their long-term mean occurrence frequencies and relationships with precipitation are investigated. Automated Lamb Weather Types classification method is applied on NCEP/NCAR daily mean sea level pressure data to determine circulation types. Northeasterly (NE) and easterly (E) types are found to be the most frequent both on the annual basis and during winter (DJF, the wettest season in the region). Circulation types with the highest rainfall potential, namely the cyclonic (C) and northerly (N), are among the least frequent; therefore they are not the dominant "rainfall modes". Instead, NE and E have the greatest contribution to the regionally averaged rainfall amount, although they do not have the highest potential to create precipitation. This shows that Marmara Region receives a substantial amount of precipitation from northerly and easterly maritime trajectories, implying a profound influence of the Black Sea on the rainfall regime in this area. However, rainfall at the stations that are far away or less affected by the Black Sea (especially at the ones in the west) occurs during types with a southerly component (S, SW and SE). In addition to the relationship between CTs and precipitation in Marmara, the significant roles of the teleconnection patterns (TPs) on CTs and precipitation mechanism were also investigated. For this purpose, five main TPs, namely North Atlantic Oscillation (NAO), Arctic Oscillation (AO), East Atlantic (EA), East Atlantic-West Russia (EAWR) and Scandinavian (SCA) patterns index values were used. EA/WR is the most influential pattern in the occurrence of CTs during winter, exhibiting positive significant (at 99% level) correlations with NE and NW; and negative ones with SW and C. the strongest association of EA/WR is with NE and NW; and negative ones with SW and C. The second most influential teleconnection pattern on the CTs of Marmara Region during DJF is the AO, whose relationship with the occurrence of NE, SW and C is in the same fashion with EA/WR. Surprisingly, the NAO, whose wintertime impact on Turkey is the most studied and documented among all teleconnection patterns; has generally weak and insignificant influence on the occurrence of CTs in Marmara Region in DJF. In water management strategies, the amount of precipitation in particular basin has a great importance. Therefore, which CTs quantitatively cause precipitation occurrence and intensity in the sub-basins of the Marmara were investigated. By applying Ward's hierarchical cluster analysis, Marmara were divided into five coherent zones, namely Black Sea-Marmara, Black Sea, Marmara, Thrace and Aegean sub-regions. Precipitation occurrence suggested that wet CTs (i.e. N, NE, NW, and C) offer a high chance of precipitation in all sub-regions. For the eastern (western) part of the region, the high probability of rainfall occurrence is shown under the influence of E (SE, S, SW) atmospheric CTs. In terms of precipitation intensity, N and C CTs had the highest positive gradients in all sub-basins of the Marmara. In addition, although Marmara and Black Sea sub-regions have the highest daily rainfall potential during NE types, high daily rainfall totals are recorded in all sub-regions except Black Sea during NW types.
Yer radarı ile karstik boşluk araştırmaları
Bu çalışmada karbonatlı kayaçların hakim olduğu Konya ilinin Ilgın ilçesinde karstik boşlukların araştırılmasına yönelik yer radarı ölçümleri yapılmıştır. Yer radarı yöntemi, yüksek frekanslı elektromanyetik prensip ile çalışan sığ jeofizik araştırma yöntemlerinden biridir. Teknolojik gelişmelerle birlikte kullanım alanı da genişleyen yer radarı, jeolojik, arkeolojik ve diğer birçok araştırma alanında kullanılmaya başlanmıştır. Karstik bölgelerde insan sağlığı ve jeoteknik açıdan tehlike barındıran bu boşlukların tespiti ile söz konusu alanlara yapılacak mühendislik yapılarının planlaması daha doğru olarak yapılabilmektedir. Bu alanlarda oluşturulacak yapılar yer altında bulunan boşluklarda gerçekleşebilecek çökmeler neticesinde ciddi hasar alma ihtimaline sahiptir. Bu nedenle karstik boşlukların oluşum şekillerinin ve yer altındaki uzanımlarının dikkatle araştırılması gerekmektedir. Yer radarının kolay uygulanabilen bir yöntem olması ve kısa zamanda geniş alanlar tarayabilmesi, bu gibi araştırmalarda yoğun olarak kullanılmasını sağlamaktadır. Çalışma sahasında 100 MHz'lik merkez frekansa sahip anten kullanarak toplamda uzunluğu 7.3 km'yi derinliği 5 m'yi bulan profil verisi elde edilmiştir. Daha önceki çalışmalar dikkate alınarak, çeşitli aşamalardan oluşan veri işlem sonuçları karşılaştırılmalı olarak değerlendirilerek en uygun veri işlem yöntemi belirlenmiştir. Elde edilen radargramlardan toplam uzunluğu 350 metreyi bulan dört tanesi seçilerek yorumlanmış ve boşluklu, çatlaklı ve deformasyonlu bölgeler belirlenmiştir. Yorumlanan verilerde detaylı olarak polarizasyon analizi ve genlik analizi yapılmıştır. Boşluk olan yapılar belirlenerek empedans değerleri üzerinden birbirleriyle olan ilişkileri ortaya konmuştur. Elde edilen sonuçlar bölgede mevcut sondaj ve jeoloji verilerinin ışığı altında değerlendirilerek karstik yapıların modellemesi yapılmıştır. Radargramlarda yorumlanan anomalilerin parametreleri hesaplanarak önce basit modelleme ardından da karmaşık modelleme yapılmıştır. Modelleme sonuçları da radargramlarda yapılan analizleri desteklemektedir. Bu tez çalışması ile karstik bölgelerde yer radarı verilerinin işlenmesinde izlenilecek yaklaşımların belirlenmesi, elde edilen radargramların yorumlanması ve modellenmesi konusunda bilgiler sunan bir kaynak ortaya konulmuştur.
Copert4 modeliyle hesaplanan karayolları emisyonlarının duyarlılığının İstanbul hava kalitesine etkisinin WRF/CMAQ model sistemiyle belirlenmesi
Istanbul, the study area and the economic capital of Turkey, is the most populated city all around Europe with a population well over 14 million. The city has faced with environmental problems due to rapid urbanization and industrialization for a couple of decades. Air pollution is one of the most challenging problems for Istanbul where studies publicized that air pollution, particulate matter pollution in specific, has various serious effects on public health. Although air pollution is caused by numerous sources ranging from industrial to biogenic activities, emissions from motor vehicles have the most adverse effects on public health as they are released at the locations with certain levels where human activity is the highest. Traffic related emissions were calculated by using COPERT 4 (COmputer Programme to calculate Emissions from Road Transport) which is vehicle emission computation software and supported by European Environment Agency (EEA). Model input data were obtained from Turkish Ministry of Environment and Urbanization, and TUVTURK, then the data were processed by R that is a software environment for statistical computing and graphics. Besides fleet distribution process based on EURO levels, engine volumes, and fuel type was done first time for Istanbul, COPERT 4 was also run with this high resolution data. High-resolution emission inventory for other sectors, which is prepared by Dr. Ulaş Im, were employed. It can be summarized from the results of this analysis that road transport itself is solely responsible for 32 percent of CO emissions, as well as playing a main role in NMVOC emissions with the contribution of 43 percent to the total NMVOC emissions inventory, and NOx emissions with the contribution of 40 percent to total NOx emissions inventory. Furthermore, overall CO, NOx and PM2.5 contributions by road transport are found as 51%, 42%, and 11%, respectively. It is also realized that impact of road transport on inventory is higher than other sources. Vehicle emissions in inventory with this vitality increase the importance of determining the sensitivity and the uncertainty of calculations. To investigate the sensitivity of COPERT 4, three scenarios are determined based on temperature and speed parameters with numerous values that are strongly affecting the calculations. Then, base case emission values were compared with obtained emission values of these three scenarios. For the each scenario COPERT model was run and emissions of road transport was obtained. Then, calculated vehicle emissions used as input for air quality model. As a result of emissions for each scenario, a conclusion can be drawn that the major pollutant is NOx and minor pollutant is PM2.5 in general, where the emissions are higher in rural areas than urban areas and than the highways When a general analysis is done on scenarios regarding to pollutants, it can be realized that there is a decrease in emissions of all kinds of pollutants except CO as speed increases, and increase in emissions of all kinds of pollutants except CO as speed decreases. On the other hand, an obvious decrease in emissions of pollutants except NMVOC is realized in the case of temperature decrease. After evaluating the effect of change in model parameters on emission rates, air quality model was run to determine how would the effect of variation on emission rates embody in air quality. Model was first run for base case, then it is tried to determine the impact on air quality by running the model for each case separately. PM2.5 is analyzed since it has a significant effect on public health although it is not one of the pollutants that are caused by vehicle emissions. The day and time was examined when the gap is at maximum between the concentrations that are calculated for fundamental cases and the concentrations that are calculated within each model cell for all scenarios. It has been realized that there is 1.5 μg/m3 (~5%) decrease in PM2.5 concentration Istanbul-wide when results from CMAQ is analyzed within Scenario-I where the speed increased by 20%. 1.5 μg/m3 rate might be considered insignificant when it is compared with other average concentrations; however, it plays a key role on public health. In Scenario-II, it was realized that there is an average 2μg/m3 decrease in PM2.5 concentration depending on decrease in speed. This study can be advanced by obtaining higher resolution data that are employed for emission calculations of vehicles such as truck, bus, etc., by preparing more detailed emission inventory, and by employing the data suiting more accurate boundary conditions for air quality model.
İstanbul'da MODELS-3/CMAQ model sistemi kullanarak düşük emisyon bölgesi çalışması
Istanbul is the most populated city of Turkey as well as one of the mega cities of the world. Due to growing population and economy, city has been experiencing the problems of air pollution. There are many studies about air pollution effects on human health in the literature. Road transport emissions are released in areas where people live intensively, therefore these emissions are important for public health. This thesis aims to identify and quantify the measures to be taken to prevent traffic-related air pollution by using WRF meteorology model and CMAQ chemistry and transport model. This study presents the first Low Emission Zone study in Istanbul by using modeling and highlights the requirements of Low Emission Zone establishment. Istanbul-specific inventory includes main anthropogenic sources on 2 km horizontal and hourly temporal resolution. Road transport emissions were obtained from COPERT emission model. Emission model results reveal that on-road traffic emissions are the main source for most of the pollutants such as CO, NMVOC and NOx, industrial combustion is responsible for high amount of SO2 emissions and solvent use and traffic are the main participants for NMVOC emissions. The spatial distribution of air pollutants has proved that the highest concentrations occur at the places where emission sources are located. But uncertainties may be occur due to the activity data, emission factors and temporal profiles used in this thesis. WRF model was run for a 11-day period, includes PM concentrations are mostly higher than EU limit value (50μg/m3), from November 2 to November 12, 2010. Model run results from the WRF simulation were compared with observations from Ataturk Airport and Goztepe air quality stations. According to statistical and time plot results WRF has captured surface temperature successfully. But this performance can be further improved by changing physical parameters of WRF. The results from the CMAQ model were compared with Aksaray air quality station based on PM10 concentrations. The statistical performance of model shows low correlation with the observations. Differences between model with measurement results can arise from many causes such as; uncertainty in the meteorological model and COPERT model, improper boundary conditions and temporal profiles and measurement errors. In order to limit traffic related air pollutants, methods and regions which have high density of population and work places were determined. Based on these criteria Historical Peninsula, Kadikoy and Maslak were selected as candidates. When transport sector emissions were reduced by 30% and given to DUMAN model, Historical Peninsula has demonstrated most significant response which is 10μg/m3 reduction in PM10 hourly concentration. Then, effect of each method on PM levels was examined by using literature studies and COPERT model. The most effective method was found as EURO 3 standard causes 85% reduction in PM10 emissions. In the case of only EURO 3, EURO 4, EUR0 5 and EURO 6 vehicles can enter the zone, hourly PM concentration differences between base situation and low emission case has reached up 35μg/m3. Overall, a low emission zone will be announced on the Historical Peninsula, will provide a significant improvement in regional air quality.
Knidos fay zonu'nun deprem geçmişini klor-36 yüzey yaş tayini yöntemiyle modelleme
Knidos is an ancient city, which is located in the south of Gulf of Gökova in Western Anatolia. The Knidos Fault Zone is situated in ancient settlement ruins on the Datça Peninsula. The recent geological and archaeological evidences point out that this ancient site has been affected by at least two crucial momentous seismic events. In the light of this information, we have carried out cosmogenic 36Cl dating in order to obtain information about the seismic history of the Knidos Fault Zone. Using cosmic-ray surface exposure dating of a well-preserved limestone fault scarp facilitates us to attain information, which reveals a seismic history of faulting events and identifies timing and recurrence interval of past major earthquakes, and slip rates of the Knidos Fault Zone. There are two distinct faults located in the study area; those are the Demeter Fault and the Mezarlık Fault. I have chosen to aim at the Mezarlık Fault on account of that it has well-preserved fault scarp. The concentration of cosmogenic 36Cl isotopes measured in 128 limestone samples from a ~15m high bedrock fault scarp helps us to reveal the fault displacement history of the Knidos fault, in the Western Turkey. Although this method can cause breakthrough to the recent studies in earth science, there are plenty of limitations and uncertainties to deal with. The important factors are latitude and air pressure (elevation) scaling factors for a constant geomagnetic field, shielding resulting from the specific geometry of active normal faults, effects of the chemical composition of the colluvial wedge, effects of denudation of the scarp surface and snow cover effects on scarp shielding. Through the modelling of the cosmogenic 36Cl nuclides, it can be understood that Mezarlık Fault might be post-glacial as a result of previous studies implied in the similar fault scarps in the Mediterranean. As oppose to all of these limitations, it has been tried to understand impacts of these factors on the target fault by using recent numerical models. I have set out to obtain accurate conclusion through correlate and compare the result with synthetic profiles and previous studies as much as possible. The slip histories modelled via concentrations of 36Cl indicate that at least three or more events occurred on the Mezarlık fault within the past 20 kyr; over 10 meters of displacement took place between early Holocene and late Pleistocene. This study was conducted with the Decision of the Council of Ministers with No. 2013/5387 on the date 30.09.2013 and was done with the permission of Knidos Presidency of excavation in accordance with the scope of Knidos Excavation and Research carried out on behalf of Selçuk University and Ministry of Culture and Tourism. This study was supported by the TÜBİTAK (Project No: 113Y436).