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961.
Temporal changes of warm-season pan evaporation in a semi-arid basin in Western Turkey 总被引:1,自引:1,他引:0
Warm-season (from May to September) pan evaporation series recorded at nine sites in semi-arid Büyük Menderes Basin in Western Turkey were analyzed for evidence of long-term changes using non-parametric Mann–Kendall test. Only two sites showed significant linear trends, one in decreasing direction and the other in increasing direction. Area-averaged normalized anomalies of pan evaporation stayed unchanged over the period 1975–2006. Based on correlation and multiple regression analysis with visual inspection of the time series plots, sunshine duration which is used as a proxy for global radiation was found to be the major factor explaining the change and variability of pan evaporation in warm-season in semi-arid Büyük Menderes Basin. Stepwise multiple regression analysis showed no significant effect of rainfall on pan evaporation, which means that the effect of complementary relationship is rather weak and even non-existent. 相似文献
962.
Forty-four boulders from moraines in two glacial valleys of Mount Erciyes (38.53°N, 35.45°E, 3917 m), central Turkey, dated with cosmogenic chlorine-36 (36Cl), indicate four periods of glacial activity in the past 22 ka (1 ka = 1000 calendar years). Last Glacial Maximum (LGM) glaciers were the most extensive, reaching 6 km in length and descending to an altitude of 2150 m above sea level. These glaciers started retreating 21.3 ± 0.9 ka (1σ) ago. They readvanced and retreated by 14.6 ± 1.2 ka ago (Lateglacial), and again by 9.3 ± 0.5 ka ago (Early Holocene). The latest advance took place 3.8 ± 0.4 ka ago (Late Holocene). Using glacier modeling together with paleoclimate proxy data from the region, we reconstructed the paleoclimate at these four discrete times. The results show that LGM climate was 8–11 °C colder than today and moisture levels were somewhat similar to modern values, with a range between 20% more and 25% less than today. The analysis of Lateglacial advance suggests that the climate was colder by 4.5–6.4 °C based on up to 1.5 times wetter conditions. The Early Holocene was 2.1–4.9 °C colder and up to twice as wet as today, while the Late Holocene was 2.4–3 °C colder and its precipitation amounts approached to similar conditions as today. Our paleoclimate reconstructions show a general trend of warming for the last 22 ka, and an increase of moisture until Early Holocene, and a decrease after that time. The recent glacier terminates at 3450 m on the northwest side of the mountain. It is a remnant from the last advance (possibly during the Little Ice Age). Repeated measurements of glacier length between 1902 and 2008 reveal a retreat rate of 4.2 m per year, which corresponds to a warming rate of 0.9–1.2 °C per century. 相似文献
963.
History and Progress of the North American Soil Geochemical Landscapes Project,2001-2010 总被引:1,自引:0,他引:1
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David B.Smith William F.Cannon Laurel G.Woodruff Francisco Moreira Rivera Andrew N.Rencz Robert G.Garrett 《地学前缘》2012,19(3):19-32
In 2007,the U.S.Geological Survey,the Geological Survey of Canada,and the Mexican Geological Survey initiated a low-density(1 site per 1600 km2,13323 sites) geochemical and mineralogical survey of North American soils(North American Soil Geochemical Landscapes Project).Sampling and analytical protocols were developed at a series of workshops in 2003-2004 and pilot studies were conducted from 2004-2007.The ideal sampling protocol at each site includes a sample from 0-5 cm depth,a composite of the soil A horizon,and a sample from the soil C horizon.The <2-mm fraction of each sample is analyzed for Al,Ca,Fe,K,Mg,Na,S,Ti,Ag,Ba,Be,Bi,Cd,Ce,Co,Cr,Cs,Cu,Ga,In,La,Li,Mn,Mo,Nb,Ni,P,Pb,Rb,Sb,Sc,Sn,Sr,Te,Th,Tl,U,V,W,Y,and Zn by inductively coupled plasma-mass spectrometry and inductively coupled plasma-atomic emission spectrometry following a near-total digestion in a mixture of HCl,HNO3,HClO4,and HF.Separate methods are used for As,Hg,Se,and total C on this same size fraction.The major mineralogical components are determined by a quantitative X-ray diffraction method.Sampling in the conterminous U.S.was completed in 2010(c.4800 sites) with chemical and mineralogical analysis currently underway.In Mexico,approximately 66% of the sampling(871 sites) had been done by the end of 2010 with completion expected in 2012.After completing sampling in the Maritime provinces and portions of other provinces(472 sites,7.6% of the total),Canada withdrew from the project in 2010.Preliminary results for a swath from the central U.S.to Florida clearly show the effects of soil parent material and climate on the chemical and mineralogical composition of soils.A sample archive will be established and made available for future investigations. 相似文献
964.
Adem Bayram Hızır Önsoy M. İhsan Kömürcü V. Numan Bulut 《Environmental Earth Sciences》2012,65(3):713-723
This paper evaluates the effects of Torul dam on the stream Harşit water quality in terms of 13 physico-chemical parameters
in the Gümüşhane Province, Eastern Black Sea Basin, Turkey. For this purpose, a study was fortnightly conducted during the
four seasons between March 2009 and February 2010. In two monitoring stations selected in the upstream and downstream of the
Torul dam, T, pH, DO and EC were determined in situ, and collected water samples were analyzed for TH, COD, NH4
+-N, NO2
−-N, NO3
−-N, TN, TKN, PO4
3−-P and MBAS. According to the Turkish Water Pollution Control Regulation (TWPCR), the stream Harşit was classified, and the
obtained results were evaluated for the values proposed by Turkish Standard (TS) 266 and World Health Organization (WHO) guidelines.
The results showed that the stream Harşit has high-quality water in terms of, T, pH, DO, COD, NH4
+-N and NO3
−-N, but slightly polluted water in terms of NO2
−-N, TKN and PO4
3−-P, and polluted for MBAS. It was concluded that Torul dam has a positive effect on the stream water quality in terms of decrease
in the annual average concentration values. The percent decreases for TH, COD, NH4
+-N, NO2
−-N, NO3
−-N, TN, TKN, PO4
3−-P and MBAS were 17.1, 20.3, 56.2, 62.6, 11.7, 11.9, 11.4, 17.8 and 71.4, respectively. The reason for these decreases is
probably due to the Torul dam reservoir where the water has a hydraulic residence time and the exposure to chemicals by aquatic
organisms or populations that ingest the water. Also, statistical analysis shows that there are significant correlations among
the studied parameters. 相似文献
965.
Hayri Baytan Ozmen Mehmet Inel Erdal Akyol Bayram Tanık Cayci Hayri Un 《Natural Hazards》2014,71(1):63-84
An earthquake has struck Simav, Kutahya, located in the western part of Turkey on May 19, 2011. This paper focuses on the evaluation of the regional damage data and detailed investigation on a set of selected reinforced concrete buildings in Simav county center. The soil properties in Simav are examined in detail using multi-channel analysis of surface wave measurements, boreholes and laboratory test data. The damages are observed to be independent of soil conditions being hilly or plain, both in regional and Simav county center level. However, a slight relation is observed: as the soil period increases, so does the damage. The most damaged buildings are the four story buildings, resembling the case after some other earthquakes in Turkey. Regarding the detailed numerical evaluations on the building set, the properties highly correlated with seismic damage are investigated. Based on the obtained findings, it is concluded that the global building properties may not be enough to establish a strong relation with damage due to the local damages at the structural member level, especially for smaller seismic events. 相似文献
966.
Adem Bayram Hızır Önsoy Murat İhsan Kömürcü Mehmet Tüfekçi 《Environmental Earth Sciences》2014,72(8):2849-2860
This paper aims to reveal the reciprocal influence of Kürtün Dam and wastewaters from the settlements on the water quality in the stream Har?it, NE Turkey. Several key water-quality indicators were measured: water temperature (T), pH, dissolved oxygen (DO), electrical conductivity, water hardness, chemical oxygen demand (COD), ammonium nitrogen (NH4 +–N), nitrite nitrogen (NO2 ?–N), nitrate nitrogen (NO3 ?–N), total Kjeldahl nitrogen (TKN), total nitrogen (TN), orthophosphate phosphorus (PO4 3?–P), and methylene blue active substances (MBAS). The monitoring and sampling studies were conducted every 15 days from March 2009 to February 2010 at two stations selected in the upstream and downstream of the Kürtün Dam. It was concluded that the Kürtün Dam Lake had a high-quality water in terms of T, pH, DO, COD, NH4 +–N, NO2 ?–N and NO3 ?–N values, but slightly polluted water with respect to TKN, PO4 3?–P, and MBAS according to the Turkish Water Pollution Control Regulation. The dam improved the stream water quality by increasing the DO concentration, and decreasing the NO2 ?–N and PO4 3?–P concentrations thanks to its hydraulic residence time despite the wastewater discharge by the nearby settlements. However, the wastewater discharge deteriorated the stream water quality increasing the COD, NH4 +–N, NO3 ––N, and TN concentrations. 相似文献
967.
The Çeltikçi (Burdur) plain is located in the southwest of Turkey and is a semi-closed basin. Groundwater is densely used as drinking, irrigation and domestic water in the plain. Hydrogeochemical processes controlling groundwater chemistry and geochemical assessment of groundwater were investigated in the Çeltikçi (Burdur/Turkey) plain. In this study, groundwater samples for two seasons were analyzed and major ion chemistry of groundwater was researched to understand the groundwater geochemistry. Two major hydrochemical facies (Ca–HCO3 and Ca–Mg–HCO3) were determined in the area. Various graphical plots and multivariate statistical analysis were used for identifying the occurrence of different geochemical processes. In the study area, weathering is one of the key geochemical processes which controlled the solute concentration in groundwater. Chemical indexes such as sodium adsorption ratio, %Na, residual sodium carbonate, magnesium hazard and permeability index were calculated and results show that groundwater is suitable for irrigation purpose except for permeability index values. Concentrations of Mn, NO3 and total hardness exceed the prescribed limits of WHO and are the major limiting parameters of groundwater use for potable and domestic purposes. 相似文献
968.
为了研究地下异常体几何及物性参数变化对井地电位法地表响应的影响规律,对垂直线源激励下的变物性参数地下异常体,采用三维有限单元法进行了正演模拟。经模拟结果表明,在浅部时异常形态清晰,随深度的增加,异常响应的形态变得模糊;地表异常响应对厚度反应不灵敏;对水平规模大小变化反应非常灵敏。这些规律将对油气田剩余油分布和注水推进前沿的确定,以及井地电位仪器分辨率的设计提供指导作用,并为井地电位法反演成像奠定相关基础。 相似文献
969.
将可拓分类识别方法引进到沉积微相识别研究中,从定性和定量二个角度研究解决沉积微相识别问题的规律和方法,建立沉积微相可拓识别模型,形成基于可拓分类理论识别沉积微相的方法。实际资料处理证明了该方法的有效性,该方法推广性好,可应用于不同区域的沉积微相识别,以及其它地质识别研究。 相似文献
970.
斜井三维VSP动校叠加处理方法 总被引:1,自引:0,他引:1
针对三维VSP目的层成像问题,在反射点计算、道集抽取、动校正和叠加等处理方法上进行了研究和总结。采用等效连续速度模型折射线算法计算反射点位置,以反射点面元抽出共反射点道集,然后进行动校正。这里采用扫描的办法计算出正确的双程垂直旅行时,再进行变叠加次数的叠加处理,得到叠加剖面。最后对射线追踪方法得到的斜井三维VSP理论记录进行了处理,验证了方法的正确性。 相似文献