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1.
J. Ignacio López-Moreno Leena Leppänen Bartłomiej Luks Ladislav Holko Ghislain Picard Alba Sanmiguel-Vallelado Esteban Alonso-González David C. Finger Ali N. Arslan Katalin Gillemot Aynur Sensoy Arda Sorman M. Cansaran Ertaş Steven R. Fassnacht Charles Fierz Christoph Marty 《水文研究》2020,34(14):3120-3133
Manually collected snow data are often considered as ground truth for many applications such as climatological or hydrological studies. However, there are many sources of uncertainty that are not quantified in detail. For the determination of water equivalent of snow cover (SWE), different snow core samplers and scales are used, but they are all based on the same measurement principle. We conducted two field campaigns with 9 samplers commonly used in observational measurements and research in Europe and northern America to better quantify uncertainties when measuring depth, density and SWE with core samplers. During the first campaign, as a first approach to distinguish snow variability measured at the plot and at the point scale, repeated measurements were taken along two 20 m long snow pits. The results revealed a much higher variability of SWE at the plot scale (resulting from both natural variability and instrumental bias) compared to repeated measurements at the same spot (resulting mostly from error induced by observers or very small scale variability of snow depth). The exceptionally homogeneous snowpack found in the second campaign permitted to almost neglect the natural variability of the snowpack properties and focus on the separation between instrumental bias and error induced by observers. Reported uncertainties refer to a shallow, homogeneous tundra-taiga snowpack less than 1 m deep (loose, mostly recrystallised snow and no wind impact). Under such measurement conditions, the uncertainty in bulk snow density estimation is about 5% for an individual instrument and is close to 10% among different instruments. Results confirmed that instrumental bias exceeded both the natural variability and the error induced by observers, even in the case when observers were not familiar with a given snow core sampler. 相似文献
2.
Seasonal variations and distributions of dissolved carbohydrate concentrations at the İzmir Bay were investigated with salinity, chlorophyll a (Chl a), and dissolved organic carbon (DOC) levels to understand their relationships. Samples were collected from surface, subsurface and bottom depths at seven stations. DOC concentrations ranged from 32.2 to 244.2 μmol/L, and in general, DOC levels increased from winter to summer, then slightly decreased in autumn. Monosaccharide (MCHO), polysaccharide (PCHO) and total dissolved carbohydrate (TDCHO) levels were found between 0.7-8.3, 0.7-19.5, and 2.6-24.6 μmol/L. DOC, MCHO, PCHO and TDCHO levels were found higher in middle-inner bays, under the influence of anthropogenic inputs, compared to outer bay. Seasonal changes of MCHO/DOC, PCHO/DOC and TDCHO/DOC ratios were statistically significant (p<0.05) and the ratios showed decrease trends from winter to summer-autumn seasons. Distributions of TDCHO/DOC ratios at wide ranges (2.5%-42.3%) indicated the presence of newly forming and degrading fractions of DOM. According to results of factor analysis, Chl a, MCHO and TDCHO were explained in the same factor groups. In conclusion, the results showed that dissolved carbohydrate levels in the İzmir Bay might be influenced by biological processes and terrestrial/anthropogenic inputs. 相似文献
3.
Izmir Bay is one of the great natural bays of the Mediterranean. The surface sediment and fish samples were collected during 1997-2009. The sediment concentrations of inner bay showed significant enrichments during sampling periods. Outer and middle bays exhibited low levels of metal enrichments except the estuary of Gediz River. The concentrations were generally higher than the background levels from the Mediterranean and Aegean except Cd and Pb levels gradually decreased. Metal EF is used as an index to evaluate anthropogenic influences of metals in sediments. Maximum metal enrichment was found for Hg in the outer bay, while Pb indicated maximum enrichment in the middle-inner bays. Metal levels were evaluated in sediments in accordance with the numerical SQG of the USEPA. The levels of fish tissues were lower than the results reported from polluted areas of the Mediterranean. The highest BAFs were detected for Hg and Cd in fish. 相似文献
4.
Sedat İnan Kadriye Ertekin Cemil Seyis Şakir Şimşek Furkan Kulak Aynur Dikbaş Onur Tan Semih Ergintav Rahşan Çakmak Ahmet Yörük Muhiddin Çergel Hakan Yakan Hüseyin Karakuş Ruhi Saatçilar Zafer Akçiğ Yıldız İravul Bekir Tüzel 《Acta Geophysica》2010,58(5):767-813
Warm and hot spring water as well as soil gas radon release patterns have been monitored in the Aegean Extensional Province of Western Turkey, alongside regional seismic events, providing a multi-disciplinary approach. In the study period of 20 months, seven moderate earthquakes with M L between 4.0 and 4.7 occurred in this seismically very active region; two earthquakes with magnitude 5.0 also occurred near the study area. Seismic monitoring showed no foreshock activity. By contrast, hydro-geochemical anomalies were found prior to these seismic events, each lasting for weeks. The anomalies occurred foremost in conjunction with dip-slip events and seem to support the dilatancy and water diffusion hypothesis. Increased soil gas radon release was recorded before earthquakes associated with strike-slip faults, but no soil radon anomalies were seen before earthquakes associated with dip-slip faults. Geochemical anomalies were also noticeably absent at some springs throughout the postulated deformation zones of impending earthquakes. The reason for this discrepancy might be due to stress/strain anisotropies. 相似文献
5.
Ali M. Hamdan Mahmoud M. Sensoy Mali S. Mansour 《Arabian Journal of Geosciences》2013,6(11):4155-4165
Riverbank filtration (RBF) is an efficient and low-cost natural alternative technology for water supply application in which surface water contaminants are removed or degraded as the infiltrating water moves from the river to the pumping wells. In this study, a full-scale RBF site consisting of three vertical wells installed 50 m from Nile bank was investigated. The RBF systems are particularly well suited for providing better water quality than withdrawal directly from the Nile River to produce drinking water for New Aswan city. The study is carried out by taking samples over 1 year from riverbank filtrates wells, Nile River (as induced surface water), and some production wells were collected and analyzed. Physicochemical and microbiological measurements such as turbidity, dissolved oxygen, total suspended solids, total organic carbon, total dissolved solids, electrical conductivity, pH, Fe, Mn, NH3, NO2, NO3, PO4, Ca, Mg, Na, K, HCO3, SO4, Cl, total bacteria, and total coliform were carried out. The results of bank filtrate were compared with those of the natural groundwater and previous reported Nile water. Chemical and bacterial quality parameters of RBF are under the allowable limits for drinking water. Moreover, bank filtration is simultaneously improved the ambient groundwater and cleaned Nile water in the studied area. Result of this full-scale RBF plant showed the effectiveness of riverbank filtration as a proven treatment technique in Nile Valley with a fraction of cost comparing to conventional surface treatment plants. 相似文献
6.
Heavy metals contamination levels at the Coast of Aliağa (Turkey) ship recycling zone 总被引：1，自引：0，他引：1
Neşer G Kontas A Unsalan D Uluturhan E Altay O Darılmaz E Küçüksezgin F Tekoğul N Yercan F 《Marine pollution bulletin》2012,64(4):882-887
Alia?a Bay is one of the most important maritime zones of Turkey where shipping activity, shipbreaking industry, steel works and petrochemical complexes exist together. Concentrations of heavy metals and organic carbon in sediment of the Alia?a Bay were investigated to evaluate an environmental risk assessment from metals contamination in 2009-2010. Comparison of the metal concentrations with average shale and Mediterranean background levels revealed that most of the samples from the Alia?a were polluted with Hg, Cd, Pb, Cr, Cu, Zn, Mn and Ni. It was found that Hg, Pb, Cu, Zn and Ni levels in Alia?a Bay exceeded the PEL values. Sediments, contaminated with Pb, Cr, Cu, Zn and Ni were considered as heavily polluted per the SQG. 相似文献
7.
基于GIS的新疆和田地区人居环境适宜性评价 总被引：1，自引：0，他引：1
人居环境是人类生存和发展的基础。运用GIS和RS技术采用单因子评价和综合评价模型,系统地归纳了国内外人居环境评价研究的理论基础和应用研究成果,利用DEM与[WTBX]NDVI[WTBZ]数据将多年平均气温、降水量、人口和GDP等要素的栅格数统一到1 km×1 km的栅格尺度,以此反映干旱区适宜性的空间分布特征。通过数字评价模型分析,结果表明：和田地区的人居环境指数介于1.139～4.495之间;整体分布景观是从和田河流域、克里雅河流域等绿洲区向北部沙漠区和南部山脉区递减,大部分地区受到自然条件的限制,人居环境中高级适宜区面积最少,占全研究区面积的1.04%,较适宜区占5.95%,中等适宜区占21.13%、难适宜区和不适宜区占71.68%,表明自然环境基础很恶劣,生态环境相当脆弱。因此,开展和田地区人居环境适宜性评价研究,对干旱区生态环境保护具有现实意义。 相似文献
8.
Seasonal variations and distributions of dissolved carbohydrate concentrations at the ?zmir Bay were investigated with salinity, chlorophyll a(Chl a), and dissolved organic carbon(DOC) levels to understand their relationships.Samples were collected from surface, subsurface and bottom depths at seven stations. DOC concentrations ranged from 32.2 to 244.2 μmol/L, and in general, DOC levels increased from winter to summer, then slightly decreased in autumn. Monosaccharide(MCHO), polysaccharide(PCHO) and total dissolved carbohydrate(TDCHO) levels were found between 0.7–8.3, 0.7–19.5, and 2.6–24.6 μmol/L. DOC, MCHO, PCHO and TDCHO levels were found higher in middle-inner bays, under the influence of anthropogenic inputs, compared to outer bay. Seasonal changes of MCHO/DOC, PCHO/DOC and TDCHO/DOC ratios were statistically significant(p0.05)and the ratios showed decrease trends from winter to summer-autumn seasons. Distributions of TDCHO/DOC ratios at wide ranges(2.5%–42.3%) indicated the presence of newly forming and degrading fractions of DOM.According to results of factor analysis, Chl a, MCHO and TDCHO were explained in the same factor groups. In conclusion, the results showed that dissolved carbohydrate levels in the ?zmir Bay might be influenced by biological processes and terrestrial/anthropogenic inputs. 相似文献
9.
Neşer G Kontas A Unsalan D Altay O Darılmaz E Uluturhan E Küçüksezgin F Tekoğul N Yercan F 《Marine pollution bulletin》2012,64(5):1055-1059
Alia?a Bay is one of the most important maritime zones of Turkey where shipping activity, shipbreaking industry, steel works and petrochemical complexes exist together. Polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons in sediment of the Alia?a Bay were investigated to evaluate an environmental risk assessment from PAHs contamination in 2009-2010. Aliphatic and PAHs diagnostic ratios were showed to be mainly petroleum-originated and pyrolitic contaminations, respectively. The TEL/PEL analysis suggests that Alia?a sediments were likely to be contaminated by acutely toxic PAH compounds. 相似文献
10.
Spawning, phases of embryonic development, intracapsular feeding mechanism and development mode of banded murex Hexaplex trunculus (Linnaeus, 1758) were examined using specimens from the Aegean Sea. In addition, the numbers and characteristics of non‐viable nurse eggs during different phases were examined in relation to the development phases of viable embryos. Females spawned between 59 and 162 egg capsules containing 306.76 ± 50.74 eggs. Trochophore larvae first appeared on the 15th day after spawning. Nurse egg consumption began on the 17th day after spawning when the embryos reached the early veliger stage. In the beginning, veligers consumed the nurse eggs by mechanically disintegrating them with velar cilia movement. From the 18th day after spawning, embryos began to consume whole nurse eggs, although mechanical disintegration continued until hatching. Viable embryos consumed the most developed nurse eggs first. The average number of nurse eggs consumed per embryo was 24.67 by the end of the intracapsular period. The average number of hatchlings was 11.95 ± 3.81 per capsule with 1321.48 ± 133.1 μm shell length. According to our observations H. trunculus shows dispersal polymorphism, with most of the hatchlings completing metamorphosis after a short planktonic non‐feeding period (up to 2 days), while others metamorphose prior to hatching. Planktonic hatchlings had both foot and well developed four‐lobed velum and minimum 1 3/4 whorls. Both hatchling types could be seen in the capsule mass from the same female. 相似文献