Assessment of ecological flow rate by flow duration and environmental management class in the Geum River, Korea   总被引：1，自引：1，他引：0  

Sangjin Lee  Joocheol Kim  Jun Wook Hur 《Environmental Earth Sciences》2013,68(4):1107-1118

This study attempted to analyze flow duration in a basin using a method to estimate environmental flow developed by the International Water Management Institute, and simulate the effects of runoff characteristics unique to a river and flow variability due to basin developments on aquatic ecosystems. To do so, KModSim, a simulation model for basin-wide water distribution, was used to assess flow duration in the Geum River basin, one of the four major river basins in Korea, by environmental management class (EMC). Flow duration curves by EMC at Sutong and Gongju sites were derived on the basis of natural flow in the Geum River basin. As a result, they were found to be consistent with the results of previous studies. Time series of mean monthly flow data by EMC were plotted together with those of simulated flow data by reservoir operation scenario; Sutong and Gongju points both showed flow behaviors corresponding almost to “A” in EMC. In addition, the characteristics of habitats by species of fish were identified through monitoring fish habitat at the Sutong site, so that optimal ecological flow rate was estimated. For this purpose, relations between flow discharge and weighted usable area for Coreoleuciscus splendidus and Pseudopungtungia nigra were projected using physical habitat simulation system, and EMCs consistent with flow duration curves (estimated taking in-stream flow) were assessed. The results or findings reported in this study are expected to serve as basic data for making a plan to efficiently monitor and manage aquatic ecosystems in the Geum River basin.  相似文献   

ALMA observations of the circumstellar envelope around EP Aqr     

Pham Thi Tuyet Nhung  Do Thi Hoai  Pham Tuan-Anh  Thibaut Le Bertre  Pierre Darriulat  Pham Ngoc Diep  Nguyen Thi Phuong  Nguyen Thi Thao  Jan Martin Winters 《天文和天体物理学研究(英文版)》2019,(3):97-110

Atacama Large Millimetre/sub-millimetre Array(ALMA) observations of CO(1–0) and CO(2–1) emissions from the circumstellar envelope of the asymptotic giant branch(AGB) star EP Aqr have been made with four times better spatial resolution than previously available. They are analysed with emphasis on the de-projection in space of the effective emissivity and flux of matter using as input a prescribed configuration of the velocity field, assumed to be radial. The data are found to display an intrinsic axisymmetry with respect to an axis making a small angle with respect to the line of sight. A broad range of wind configurations, from prolate(bipolar) to oblate(equatorial) has been studied and found to be accompanied by significant equatorial emission. Qualitatively, the effective emissivity is enhanced near the equator to produce the central narrow component observed in the Doppler velocity spectra and its dependence on star latitude generally follows that of the wind velocity with the exception of an omni-present depression near the poles. In particular, large equatorial expansion velocities produce a flared disc or a ring of effective emissivity and mass loss. The effect on the determination of the orientation of the star axis of radial velocity gradients, and possibly competing rotation and expansion in the equatorial disc, is discussed. In general,the flux of matter is found to reach a broad maximum at distances of the order of 500 AU from the star.Arguments are given that may be used to favour one wind velocity distribution over another. As a result of the improved quality of the data, a deeper understanding of the constraints imposed on morphology and kinematics has been obtained.  相似文献   

Tide-related Changes in mRNA Abundance of Aromatases and Estrogen Receptors in the Ovary and Brain of the Threespot Wrasse <Emphasis Type="Italic">Halichoeres trimaculatus</Emphasis>     

Dae-Ju Oh  Sung-Pyo Hur  Selma Bouchekioua  Yuki Takeuchi  Shingo Udagawa  Neelakanteswar Aluru  Yong-Ju Park  Ji-Gweon Park  Se-Jae Kim  Thomas W. Moon  Mathilakath M. Vijayan  Akihiro Takemura 《Ocean Science Journal》2018,53(2):239-249

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Molecular expression of opsin gene in growing juvenile mackerel (<Emphasis Type="Italic">Scomber japonicus</Emphasis> Houttuyn)     

Eung-Oh Kim  Seong-Jong Yoon  Kyoung-Hyun Park  Dae-Hyun Kim  Jeung-Wan Do  Eun-Seob Cho 《Ocean Science Journal》2009,44(4):215-220

Fish have developed color vision that is closely adapted to their photic environments, where both spectral sensitivity and the number of visual opsins are influenced. The mackerel used in this study is one of the most important fishery stocks in Korea. The opsin gene of the mackerel juveniles after 20 days in hatching was isolated and characterized based on the molecular study of visual photoreceptor. The full-length mackerel opsin gene was obtained by PCR amplification of genomic DNA, as well as cDNA synthesis. Sequence analysis of the opsin gene showed that it contained a 1,080 bp open reading frame encoding 360 amino acids. Based on Schiff’s base formation (S114, K119), glycosylation (E3, F37) and palmitoylation (S281, 282), the deduced amino acid sequence had a typical rod opsin. The mackerel and Gempylus serpens showed 73.7% DNA homology on opsin gene, which was higher than any other of investigated species. In the analysis of phylogenetic relationship, the genetic placement of the mackerel is closer to that of Scombroidei than Labroidei, with supporting somewhat strong bootstrap value. In the analysis of Northern and RT-PCR, the probed products were observed only in rapidly growing juveniles. These findings indicate that in mackerel opsin mRNA expression can be detected in day-20 hatching larvae. It may play an important role in stimulating growth hormone.  相似文献   

The phase difference effects on 3-D structure of wave pressure acting on a composite breakwater     

D.-S. Hur  K.-H. Lee  G.-S. Yeom   《Ocean Engineering》2008,35(17-18):1826-1841

In designing the coastal structures, the accurate estimation of the wave forces on them is of great importance. In this paper, the influences of the phase difference on wave pressure acting on a composite breakwater installed in the three-dimensional (3-D) wave field are studied numerically. We extend the earlier model [Hur, D.S., Mizutani, N., 2003. Coastal Engineering 47, 329–345] to simulate 3-D wave fields by introducing 3-D Navier–Stokes solver with the Smagorinsky's sub-grid scale (SGS) model. For the validation of the model, the wave field around a 3-D asymmetrical structure installed on a submerged breakwater, in which the complex wave deformations generate, is simulated, and the numerical solutions are compared to the experimental data reported by Hur, Mizutani, Kim [2004. Coastal Engineering (51, 407–420)]. The model is then adopted to investigate 3-D characteristics of wave pressure and force on a caisson of composite breakwater, and the numerical solutions were discussed with respect to the phase difference between harbor and seaward sides induced by the transmitted wave through the rubble mound or the diffraction. The numerical results reveal that wave forces acting on the composite breakwater are significantly different at each cross-section under influence of wave diffraction that is important parameter on 3-D wave interaction with coastal structures.  相似文献   

Glacier Extent and Volume Change （1966-9000） on the Su-lo Mountain in Northeastern Tibetan Plateau, China     

WANG Yetang HOU Shugui HONG Sungmin HUR Soon Do LIU Yaping 《山地科学学报》2008,5(4)

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Impact of the spatial variability of daily precipitation on hydrological projections: A comparison of GCM‐ and RCM‐driven cases in the Han River basin,Korea     

Moon‐Hwan Lee  Eun‐Soon Im  Deg‐Hyo Bae 《水文研究》2019,33(16):2240-2257

In this study, we investigate the impact of the spatial variability of daily precipitation on hydrological projections based on a comparative assessment of streamflow simulations driven by a global climate model (GCM) and two regional climate models (RCMs). A total of 12 different climate input datasets, that is, the raw and bias‐corrected GCM and raw and bias‐corrected two RCMs for the reference and future periods, are fed to a semidistributed hydrological model to assess whether the bias correction using quantile mapping and dynamical downscaling using RCMs can improve streamflow simulation in the Han River basin, Korea. A statistical analysis of the daily precipitation demonstrates that the precipitation simulated by the GCM fails to capture the large variability of the observed daily precipitation, in which the spatial autocorrelation decreases sharply within a relatively short distance. However, the spatial variability of precipitation simulated by the two RCMs shows better agreement with the observations. After applying bias correction to the raw GCM and raw RCMs outputs, only a slight change is observed in the spatial variability, whereas an improvement is observed in the precipitation intensity. Intensified precipitation but with the same spatial variability of the raw output from the bias‐corrected GCM does not improve the heterogeneous runoff distributions, which in turn regulate unrealistically high peak downstream streamflow. GCM‐simulated precipitation with a large bias correction that is necessary to compensate for the poor performance in present climate simulation appears to distort streamflow patterns in the future projection, which leads to misleading projections of climate change impacts on hydrological extremes.  相似文献   

Geochemical background of potentially toxic trace elements in reclaimed soils of the abandoned pyrite–uranium mine (south-central Poland)     

A. Gałuszka  Z. Migaszewski  A. Duczmal-Czernikiewicz  S. Dołęgowska 《International Journal of Environmental Science and Technology》2016,13(11):2649-2662

Spatial distribution patterns of As, Ba, Cd, Cr, Cu, Mn, Ni, Pb, U and Zn were determined in topsoil samples collected after 40 years of chemical remediation conducted in the inoperative “Staszic” pyrite–uranium mine in the Holy Cross Mountains, south-central Poland. Soil samples were taken from 58 sites using a systematic random sampling design. Selected samples were subjected to an X-ray diffractometry analysis on bulk soils and separated clay fractions. Hematite, goethite and gypsum are common mineral phases in soil samples. Technogenic soils developed on reclaimed mine spoils show uniform spatial element distribution patterns and additionally a distinct enrichment in As, Pb, Mn, U and Zn. Mineral and chemical composition of soils vs. rocks points to the lithogenic source of the determined elements. The results of chemical analysis have been used for evaluation of geochemical background of trace elements in the study area with the iterative 2σ-technique. This investigation shows that using mean crustal element concentrations (Clarke values) as proxies of threshold values in soils are not useful for determination of strongly positive geochemical anomalies. A modified enrichment factor, i.e. a local enrichment factor, is proposed for identification of sites where soils are contaminated.  相似文献   

Analysis of sediment distribution and transport for mitigation of sand deposition hazard in Tam Quan estuary,Vietnam     

Do Minh Duc  Dinh Xuan Thanh  Dinh Thi Quynh  Patrick McLaren 《Environmental Earth Sciences》2016,75(9):741

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Geotechnical Behavior of Recycled Copper Slag-Cement-Treated Singapore Marine Clay     

Sanjay Kumar Bharati  Soon Hoe Chew 《Geotechnical and Geological Engineering》2016,34(3):835-845

Copper slag is a by-product obtained from production of copper metal. As copper slag contains silica and alumina, it may exhibit pozzolanic property, and hence it may be re-use in ground improvement applications as a partial replacement of cement. Present study evaluates systematically the possible pozzolanic property of copper slag as well as studies the effect of copper slag on engineering properties of cement-treated clay. X-rays diffraction method was employed to assess the possible pozzolanic property of copper slag. Effect of copper slag on engineering properties (i.e. compressive strength and compressibility) of cement-treated clay was studied with samples prepared with constant water content and workability. The test results showed that with sufficient curing time and at constant workability, the compressive strength of cement-treated clay was found to be increased with increasing amount of copper slag at high cement content but the compressive strength remained the same with increasing amount of copper slag at low cement content. Compressibility of cement-treated clay was found to be unchanged with increasing amount of copper slag. It was concluded that copper slag can be used as partial replacement of cement in treating soft marine clay.  相似文献