Evaluating climate change effects on runoff by statistical downscaling and hydrological model GR2M

The main purpose of this study is to evaluate the impacts of climate change on Izmir-Tahtali freshwater basin, which is located in the Aegean Region of Turkey. For this purpose, a developed strategy involving statistical downscaling and hydrological modeling is illustrated through its application to the basin. Prior to statistical downscaling of precipitation and temperature, the explanatory variables are obtained from National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis data set. All possible regression approach is used to establish the most parsimonious relationship between precipitation, temperature, and climatic variables. Selected predictors have been used in training of artificial neural networks-based downscaling models and the trained models with the obtained relationships have been operated to produce scenario precipitation and temperature from the simulations of third Generation Coupled Climate Model. Biases from downscaled outputs have been reduced after downscaling process. Finally, the corrected downscaled outputs have been transformed to runoff by means of a monthly parametric hydrological model GR2M to assess the probable impacts of temperature and precipitation changes on runoff. According to the A1B climate scenario results, statistically significant trends are foreseen for precipitation, temperature, and runoff in the study basin.     

Stratigraphic organisation,spatial distribution,palaeoenvironmental reconstruction,and demise of Lower Cretaceous (Barremian-lower Aptian) carbonate platforms of the Western Pontides (Black Sea region,Turkey)

Barremian-Lower Aptian platform carbonates (“Urgonian limestones”) of the northern margin of the Istanbul zone extend from Zonguldak to the Kurucasile area along the Black Sea coast. New stratigraphic data on the “Inpiri” Formation of the Inpiri-Kurucasile area are based on the identification of calcareous algae, foraminifera, and rudists. They show that this lithostratigraphic unit is stratigraphically and lithologically equivalent to the Ökü?medere Formation from Zonguldak. Some of the biostratigraphic markers are reported for the first time in Anatolia. Foraminifera are represented by several forms with a significant biostratigraphic potential used to distinguish the Barremian from the lower Aptian. Lower Aptian beds also yield relatively advanced caprinid rudists.The Ökü?medere Formation is relatively thin, terrigeneous-rich, and rudist-free or rudist-poor in the Kurucasile sector, and thick, terrigeneous-poor, and rudist-rich from Amasra to Zonguldak, with a set of marker beds including either charophytes or Palorbitolina and capped by a coral unit underlying ammonite bearing marls. Terrigeneous-rich carbonates from the eastern sector are interpreted as marginal marine coastal, infralittoral environments and grade distally, northward, to marly basinal sediments. By contrast “Urgonian type” limestones from the Zonguldak-Amasra region possess a wide extent and no transition to coastal or basinal sediments has been observed. A transition from a typical platform westward to a mixed siliciclastic-carbonate ramp eastward was controlled by both the nature of the adjacent exposed area and tectonic factors affecting the overall continental margin that is a northward downwarping. The exposed area was flanked southward by a belt of coastal siliciclastics grading southward and eastward to deep water sediments of the Ulus basin. In mid-Bedoulian time, carbonate platform demise from the western region was drowned below deeper marly sediments whereas the eastern siliscilastic-carbonate ramp was buried below coastal clastics.     

Comparison of Drilling Performance of Chisel and Button Bits on the Electro Hydraulic Driller

Electro hydraulic drillers have been widely used in mining for drilling and roof-bolting. In the drilling process, the performance of the machine is predicted by selecting an appropriate bit type prior to drilling operations. In this paper, a series of field drilling studies were conducted in order to examine and compare the performance of chisel and button bits including wear on the bits. The effects of taper angle on chisel bits, which are at angles of 105°, 110° and 120°, were investigated in terms of rate of penetration, instantaneous drilling rate and specific energy. The results of drilling and abrasivity tests performed in the laboratory supported the outcome of the field studies. Based on laboratory studies and field observations, it was proven that the conglomerate encountered, though it is very abrasive, is easy to drill. The cutter life in the encountered series is also longer in sandstone formation compared to the conglomerate. Additionally, button bits resulted in lower specific energy and higher penetration rates relative to chisel bits, regardless of their taper angles. The results were also supported with statistical analyses.     

Petrology and geochemistry of post-collisional Middle Eocene volcanic units in North-Central Turkey: Evidence for magma generation by slab breakoff following the closure of the Northern Neotethys Ocean

The Eocene volcano-sedimentary units of Northern Anatolia are confined into a narrow zone trending parallel to the Intra Pontide and İzmir–Ankara–Erzincan sutures, along which the northern branch of the Neotethys Ocean was closed during a period between Late Maastrichtian and Paleocene. The Middle Eocene formations overlie both the imbricated and highly deformed units of the suture zone, which are Paleocene or older in age, as well as the formations of adjacent continental blocks with a regional disconformity. Therefore, they can be regarded to be post-collisional. These units are composed of subaerial to shallow marine sedimentary beds (i.e. the Örencik formation) at the base and a subaerial volcanic unit (i.e. the Hamamözü formation) in the middle and at the top. This sudden facies change from marine to subaerial environment in the Middle Eocene is a common phenomenon across northern Turkey, implying that a regional uplift event occurred possibly across the suture zone before the initiation of the volcanism during Lutetian. The Middle Eocene lavas span the whole compositional range from basalts to rhyolites and display a calc-alkaline character except for alkaline to mildly-alkaline lavas from the top of the sequence. All lavas display a distinct subduction signature. Our geochemical data indicate that calc-alkaline lavas were derived from a subduction-modified source, whereas alkaline to mildly-alkaline lavas of the late stage were possibly sourced by an enriched mantle domain. Magmas evolved in magma chambers emplaced possibly at two different crustal levels. Magmas in deeper (> 13 km) and possibly larger chambers fractionated hydrous mafic minerals (e.g. amphibole and biotite), two pyroxenes and plagioclase and assimilated a significant amount of crustal material. Intermediate to acid calc-alkaline lavas and pyroclastics were derived from these chambers. Magmas in the shallower chambers, on the other hand (~ < 12 km), crystallized anhydrous mineral assemblages, assimilated little or no crustal material and fed basic to intermediate lavas in the region. Both deep and shallow chambers were periodically replenished by mafic magmas. We argue that a slab breakoff model explains better than any alternative model (i) why the volcanism during the Middle Eocene was confined into a rather narrow belt along the suture zone, (ii) why it initiated almost contemporaneous with a regional uplift after the continental collision event, (iii) why it postdated arc volcanism along the Pontides in the north by 15–20 My, (iv) why it assimilated significant amount of crustal material, and (v) why alkalinity of lavas increased in time.     

Investigation of the Possibility of Copper Removal from Industrial Leachate by Raw and Calcined Phosphogypsum: D‐Optimal and Taguchi Designs

In the present study, the removal of Cu(II) was evaluated by raw and calcined phosphogypsum (PG) as an industrial product. The role of experimental factors on the removal of Cu(II) was examined by using D‐optimal and Taguchi designs. The experimental factors and their related levels were selected as initial pH of 3–6–8, adsorbent content of 5, 10, and 25 g L^?1, contact time of 5, 10, and 20 min, and temperature of 20, 40, and 60°C. The results are evaluated by ANOVA test to extract important experimental factors and their levels. The performances of the suggested factorial designs were then compared and regression models that took into account the significant main and interaction effects were suggested. Taguchi design was found as a reliable solution with less number of experiments for adsorption studies with the optimized values. The resultant removal efficiency is calculated as 78.34%. The results revealed that calcined PG is an appropriate adsorbent for Cu(II) removal from leachate of industrial waste.     

Comparison of TRMM-based flood indices for Gaziantep,Turkey

Floods are the most common natural disasters threatening the welfare of humanity. Gaziantep, a city located in a semi-arid region of Turkey, is occasionally flooded, and in May 2014, a flood not only caused property damage, but also resulted in the death of a lady who became trapped in flood waters. The fatality and property damage of flash floods arise from the limited response time for remediation. Despite improvements in numerical weather predictions, forecasting flash floods is not easy. Due to its frequent observations, Tropical Rainfall Measuring Mission (TRMM) Multi-Satellite Precipitation Analysis (TMPA) real-time (RT) 3B42RT data are tested for Gaziantep flood predictions in this study. During TRMM era, six floods occurred in Gaziantep. Three-hourly 3B42RT data covering the 2000- to 2014-year period indicated high rain rates during months in which floods were observed. Also daily variation of rainfall was well represented. High-intensity rain (HIR), cumulative distribution functions (CDF) and Gaziantep Flood Index (GAFI) indices are developed for flood characterization. HIR, calculated as 10 mm/h, detected October and December of 2010 floods. CDFs with 99, 98.5, 95 and 91.3% indicated 4 floods occurred in August 2005, June 2007, October 2010 and December 2010, respectively. GAFI was able to detect 4 out of 6 occurrences (August 2005, June 2007, October 2010 and December 2010) as values ranging from 1 to 2.63 are selected for monthly precipitation. In the missed occurrence, 3B42RT did not indicate any rainfall. Although only rain rates are used in flood characterization, the results are promising, and the simplicity of the methodology favors its usage. Also, methodology can easily be implemented to TRMM following missions such as Global Precipitation Measurement Mission.     

Hydrogeochemical and isotopic investigation of the Kolan geothermal field, southeastern Turkey

The Kolan geothermal field is located 24 km northwest of the Karakoçan area of Elaz city in southeastern Turkey. The Keban crystallized limestone of Permo-Carboniferous age is the oldest unit in the area. This unit is overlain by the middle-upper Eocene Krkgeçit formation consisting of conglomerate, sandstone, limestone and marl alternations. The youngest unit in the area is the Upper Miocene-Lower Pliocene Karabakr formation consisting of basalt, andesite and tuffs. Thermal Springs in the Kolan field issue along two major fault zones. The temperature of the hot springs is between 38°C and 45°C. Thermal waters in the area are heated by the geothermal gradient. The waters are classified as hot or very hot and as brackish waters. On the basis of International Association of Hydrogeologists Classification (IAH), waters are grouped as Ca–Na-HCO₃–CO₂-bearing thermal and mineral waters. Chemical analyses indicate a chemical composition of Ca>(Na+K)>Mg - HCO₃>SO₄>Cl. Saturation calculations reveal that the waters are oversaturated with respect to calcite, dolomite and aragonite while undersaturated with respect to gypsum, anhydrite and halite minerals. On the basis of ¹⁸O, ²H and ³H isotope data, Kolan waters are of meteoric origin, recharged from high elevations and then circulated deeply.     

Absolute and geometric parameters of W UMa type contact binary TYC 1174-344-1

We present the results of our investigation on the geometrical and physical parameters of W UMa-type binary TYC1174-344-1 from analyzed CCD (BVRI) light curves and radial velocity data. The photometric data were obtained in 2009 at Ankara University Observatory (AUO) and the spectroscopic observations were made in 2008 at Astrophysical Observatory of Asiago (Italy). Light and radial velocity observations were analyzed simultaneously by using the well-known Wilson–Devinney (2007 revision) code to obtain absolute and geometrical parameters. According to our solutions, the system is found to be a low mass-ratio A-type W UMa system. Combining our photometric solution with the spectroscopic data, we derived mass and radii of the eclipsing system as M₁ = 1.381 M_⊙, M₂ = 0.258 M_⊙, R₁ = 1.449 R_⊙ and R₂ = 0.714 R_⊙. We finally discussed the evolutionary condition of the system.