Evaluation of weir construction on water quality related to algal blooms in the Nakdong River     

Jungsu Park  Dingbao Wang  Woo Hyoung Lee 《Environmental Earth Sciences》2018,77(11):408

Understanding the effect of various environmental factors on algal blooms is essential for proper management of water resources. Eight weirs were constructed on the Nakdong River in South Korea between 2010 and 2011 to manage water resources and deal with possible floods and droughts. In this study, water quality observation data were collected from eight representative monitoring sites in the Nakdong River between 2001 and 2016. Particularly, the effect of the weirs construction on water retention time was statistically analyzed in terms of algal growth and other important water quality parameters. While there was slight increase of water temperature (0.8 °C) over 16 years, the concentrations of total phosphorous (TP) and total nitrogen (TN) decreased by 62.3, and 12.9%, respectively, after the construction of weirs. This TP decrease was noticeable, but still high enough to maintain the eutrophic state of the river. Correlation statistical analysis suggests that the Chl-a concentration is positively affected by the changes of TP, TN and chemical oxygen demand. However, there was no direct correlation between Chl-a concentration and the increased water retention time from the weir construction.  相似文献   

Development of a natural analogue database to support the safety case of the Korean radioactive waste disposal program     

Min Hoon Baik  Tae-Jin Park  In Young Kim  Jongtae Jeong  Kyung Woo Choi 《Swiss Journal of Geoscience》2015,108(1):139-146

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Emergency planning and mitigation at Vesuvius: A new evidence-based approach     

P.J. Baxter  W.P. Aspinall  A. Neri  G. Zuccaro  R.J.S. Spence  R. Cioni  G. Woo 《Journal of Volcanology and Geothermal Research》2008

Disasters from explosive volcanic eruptions are infrequent and experience in emergency planning and mitigation for such events remains limited. The need for urgently developing more robust methods for risk assessment and decision making in volcanic crises has become increasingly apparent as world populations continue to expand in areas of active explosive volcanism. Nowhere is this more challenging than at Vesuvius, Italy, with hundreds of thousands of people living on the flanks of one of the most dangerous volcanoes in the world. We describe how a new paradigm, evidence-based volcanology, has been applied in EXPLORIS to contribute to crisis planning and management for when the volcano enters its next state of unrest, as well as in long-term land-use planning. The analytical approach we adopted enumerates and quantifies all the processes and effects of the eruptive hazards of the volcano known to influence risk, a scientific challenge that combines field data on the vulnerability of the built environment and humans in past volcanic disasters with theoretical research on the state of the volcano, and including evidence from the field on previous eruptions as well as numerical simulation modelling of eruptive processes. Formal probabilistic reasoning under uncertainty and a decision analysis approach have provided the basis for the development of an event tree for a future range of eruption types with probability paths and hypothetical casualty outcomes for risk assessment. The most likely future eruption scenarios for emergency planning were derived from the event tree and elaborated upon from the geological and historical record. Modelling the impacts in these scenarios and quantifying the consequences for the circumvesuvian area provide realistic assessments for disaster planning and for showing the potential risk–benefit of mitigation measures, the main one being timely evacuation, but include for consideration protecting buildings against dilute, low dynamic pressure surges, and temporary roof supports in the most vulnerable buildings, as well as hardening infrastructure and lifelines. This innovative work suggests that risk-based methods could have an important role in crisis management at cities on volcanoes and small volcanic islands.  相似文献   

Impact of Temperature,Low pH and NH 4 + Enrichment on Ecophysiological Responses of a Green Tide Species Ulva australis Areschoug     

Cicilia S. B. Kambey  Jin Woo Kang  Ik Kyo Chung 《Ocean Science Journal》2020,55(1):115-127

Ulva are ubiquitous and opportunistic green algae species that easily adapt to various environmental conditions. These algae are responsible for the green  相似文献   

Physiological Responses of Cultured Seaweed Pyropia yezoensis to Phosphorous Limitation in the Nakdong River Estuary,Korea     

Kim  Sangil  Yoon  Sang Chol  Yoo  Man Ho  Park  Kyung Woo  Park  Sang Rul  Youn  Seok-Hyun 《Ocean Science Journal》2019,54(1):129-139

Ocean Science Journal - Pyropia yezoensis cultured in the estuary of the Nakdong River in Korea is an important fisheries resource for the local economy. Over the past few decades, the...  相似文献   

Erratum to “A WIMP detector with two-phase xenon” [Astropart. Phys. 12 (2000) 373–377]     

D. Cline  A. Curioni  A. Lamarina  G. Mannocchi  S. Otwinowski  L. Periale  R. Periale  P. Picchi  F. Pietropaolo  H. Wang  J. Woo 《Astroparticle Physics》2000,13(4):373

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Quantitative estimation of intertidal sediment characteristics using remote sensing and GIS     

Jong-Kuk Choi  Joo-Hyung Ryu  Yoon-Kyung Lee  Hong-Rhyong Yoo  Han Jun Woo  Chang Hwan Kim 《Estuarine, Coastal and Shelf Science》2010

High spatial resolution satellite data (IKONOS) combined with in situ data was used to quantitatively estimate the spatial distribution of tidal flat characteristics for the Hwangdo tidal flat, Cheonsu Bay, Korea. The classification result was accurate in terms of a comparison with the in situ data, and the overall accuracy was 90.7%, which confirmed the validity of the classification. GIS analysis based on a probabilistic model was applied to a quantitative estimation of the relationship between each surface sediment facies and the spectral reflectance. Mud flat facies showed a high positive correlation (R² = 0.91), and sand flat facies showed a high negative correlation (R² = 1.00), which was a good reflection of the sedimentary characteristics of Hwangdo tidal flat. Relationships between each sediment facies and DEM also showed good agreement with the topographic characteristics in the study area. The study revealed that intertidal surface sediment classification using high resolution remote sensing imagery and in situ data successfully shows spectral and topographic characteristics of the study area. It was noted that spectral reflectance was affected by a combination of environmental factors, including grain size, topography, and remnant surface water. It is possible to determine the type of tidal flat through quantitative estimates of the spatial distribution of surface sediments according to their spectral reflectance.  相似文献   

Early Observations by the GOES-13 Solar Extreme Ultraviolet Sensor (EUVS)     

J. S. Evans  D. J. Strickland  W. K. Woo  D. R. McMullin  S. P. Plunkett  R. A. Viereck  S. M. Hill  T. N. Woods  F. G. Eparvier 《Solar physics》2010,262(1):71-115

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A developed soil column test device for measuring the electrical conductivity breakthrough curves     

Xiaoqiang Dong  Xiaofeng Liu  Heesoo Woo  Junboum Park 《Environmental Earth Sciences》2014,72(9):3715-3722

To obtain the breakthrough curves without efforts required in the sampling and chemical analysis, a new soil column test device was developed. The device can conduct time-continuous electrical conductivity (EC) measurements without disturbing the soil matrix at all stages of the test. This device is composed of soil column, channel selector, LCR meter, and data logger. The soil column employs three 4-electrode sensors installed at different positions. To verify its applicability, the electrical conductivity breakthrough curves at different distances have been obtained with the use of five different species influent solutions (KCl, NaCl, CaCl₂, MgCl₂, and seawater). Results showed that the EC breakthrough curves and the transport parameters (the pore-water velocity, the dispersion coefficient, and the dispersivity) are very reasonable, and understand the one-dimensional steady flow exactly. The developed soil column test device proposed in this study provides a nondestructive, convenient, and inexpensive means of obtaining EC breakthrough curves.  相似文献   

Sequestration of arsenate from aqueous solution using 2-line ferrihydrite: equilibria,kinetics, and X-ray absorption spectroscopic analysis     

Woo Chun Lee  Soon-Oh Kim  James Ranville  Seong-Taek Yun  Sun Hee Choi 《Environmental Earth Sciences》2014,71(8):3307-3318

Arsenic(V), as the arsenate (AsO₄ ^3?) ion and its conjugate acids, has a strong affinity on Fe, Mn, and Al (oxyhydr)oxides and clay minerals. Removal of arsenate from aqueous solution by poorly crystalline ferrihydrite (hydrous ferric oxide) via a combination of macroscopic (equilibria and kinetics of sorption) and X-ray absorption spectroscopic studies was investigated. The removal of arsenate significantly decreased with increasing pH and sorption maxima of approximately 1.994 mmol/g (0.192 mol_As/mol_Fe) were achieved at pH 2.0. The Langmuir isotherm is most appropriate for arsenate sorption over the wide range of pH, indicating that arsenate sorption preferentially takes place at relatively homogenous and monolayer sites rather than heterogeneous and multilayer surfaces. The kinetic study demonstrated that arsenate sorption onto 2-line ferrihydrite is considerably fast, and sorption equilibrium was achieved within the reaction time of 2 h. X-ray absorption near-edge structure spectroscopy indicates no change in oxidation state of arsenate following interaction with the ferrihydrite surfaces. Extended X-ray absorption fine structure spectroscopy supports the efficient removal of arsenate by the 2-line ferrihydrite through the formation of highly stable inner-sphere surface complexes, such as bidentate binuclear corner-sharing (²C) and bidentate mononuclear edge-sharing (²E) complexes.  相似文献