Assessing drought conditions through temporal pattern,spatial characteristic and operational accuracy indicated by SPI and SPEI: case analysis for Peninsular Malaysia     

Fung  K. F.  Huang  Y. F.  Koo  C. H. 《Natural Hazards》2020,103(2):2071-2101

Natural Hazards - A strong understanding of severe drought conditions is important for its mitigation and damage alleviation. Given the Peninsular Malaysia’s drought vulnerability and its...  相似文献   

Hydrochemistry of groundwaters in a spa area of Korea: an implication for water quality degradation by intensive pumping     

Kangjoo Kim  Min‐Ho Koo  Sang‐Ho Moon  Byoung‐Woo Yum  Kwang‐Sik Lee 《水文研究》2005,19(2):493-505

A geochemical study was carried out in a small spa area (Onyang Spa, Korea) where intensive pumping of deep thermal groundwater (1 300 000 m³ year⁻¹) is taking place. This has caused the deep fractures to lose their artesian pressure and the upper shallow fractures have been encroached by shallow, cold waters. To quantify the influence of long‐term heavy pumping on the quality of the geothermal water, groundwater sampling and chemical analysis, water‐level measurement, and well loggings were performed for the selected deep thermal wells and shallow cold wells. Chemical analysis results indicate a big contrast in water chemistry and origins between the two water types. Shallow groundwater shows a wider concentration ranges in solutes that are closely related to human activity, illustrating the water's vulnerability to contamination near the land surface. Plots of water chemistry as a function of fluoride reveal that the quality of the thermal water was greatly influenced by the shallow, cold groundwater and that intensive pumping of the deep thermal groundwater has caused the introduction of shallow groundwater into the deeper fractures. Although the deep and the shallow fractures were piezometrically separated to some extent, a mixing model based on fluoride and nitrate indicated that the cold‐water fractions in the thermal wells are up to 50%. This suggests that the thermal water is faced with water quality degradation by the downward flow of the shallow, cold water. Restriction on the total of all the pumpage permits per unit area is suggested to restore the artesian pressure of the deep thermal aquifer and to prevent cold‐water intrusion in the study area. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

The differentiated impact of emissions trading system based on company size     

Yoonmo Koo  Yoonha Lee  Yong-gun Kim 《Climate Policy》2019,19(7):923-936

Most countries implementing an emissions trading system (ETS), such as EU member states, California in the US, or South Korea, are generally targeting large sized companies, which consume energy above a specific threshold. However, previous studies using computable general equilibrium (CGE) models have analyzed climate policies without considering company size. This may have led to inaccurate results because the impacts of climate policy would differ depending on the coverage of regulated companies. Accordingly, this study examines the environmental and economic impacts of greenhouse gas emission reduction policies, assuming policy results vary by firm size, as covered by the Korean emission trading system. To this end, a CGE model with a separate social accounting matrix based on company size is used to compare three scenarios that reflect different types of carbon pricing methods. The results show that greenhouse gases will be reduced to a lower extent and utility will decrease more if mitigation policies are only imposed to large companies.

Key policy insights

• Carbon pricing policies should consider the different impacts on companies of different sizes and industry sectors.

• Without considering the different sizes of companies covered by an ETS, the expected carbon price and its economic impact will be underestimated.

• Small and medium-sized companies will face more negative impacts than large companies in some industry sectors under an ETS, even if the mitigation burden is only faced by large companies.

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The simulation of aerosol transport over East Asia region   总被引：1，自引：0，他引：1  

Youn-Seo Koo  Sung-Tae Kim  Hui-Young Yun  Jin-Seok Han  Jung-Young Lee  Ki-Hyun Kim  Eui-Chan Jeon 《Atmospheric Research》2008,90(2-4):264-ICNAA07

This study was carried out to understand the contribution of PM10 from China emission to Seoul Metropolitan Area (SMA) during high concentration period in January, 2007. The hourly PM10 concentration in Seoul Metropolitan Area had reached up to over 150 μg/m³ on 17th and 23rd of January in 2007. The aerosol transports from China along the Northwestern wind becomes the background concentrations in Korea and the assessment of the amount of contribution from China is very important in managing the air quality improvement plan in SMA.The U.S. EPA's Models-3/CMAQ (Community Multiscale Air Quality) was used to simulate PM10 concentration. The CMAQ performance was evaluated by comparing with the measurements in SMA for the episode period. The predictions were relatively in a good agreement with the measurements.The results show that the PM10 transport from China to Korea is significant and its contribution reaches up to 80% in the episode period. In order to assess more extensively the aerosol transport in East Asia region, the study to run the model in full year with speciated PM component measurements in super site is underway.  相似文献   

Mineralogical, fluid inclusion, and stable isotope constraints on mechanisms of ore deposition at the Samgwang mine (Republic of Korea)—a mesothermal, vein-hosted gold–silver deposit     

Bong Chul Yoo  Hyun Koo Lee  Noel C. White 《Mineralium Deposita》2010,45(2):161-187

The Samgwang mine is located in the Cheongyang gold district (Cheonan Metallogenic Province) of the Republic of Korea. It consists of eight massive, gold-bearing quartz veins that filled NE- and NW-striking fractures along fault zones in Precambrian granitic gneiss of the Gyeonggi massif. Their mineralogy and paragenesis allow two separate vein-forming episodes to be recognized, temporally separated by a major faulting event. The ore minerals occur in quartz and calcite of stage I, associated with fracturing and healing of veins. Hydrothermal wall-rock alteration minerals of stage I include Fe-rich chlorite (Fe/(Fe+Mg) ratios 0.74-0.81), muscovite, illite, K-feldspar, and minor arsenopyrite, pyrite, and carbonates. Sulfide minerals deposited along with electrum during this stage include arsenopyrite, pyrite, pyrrhotite, sphalerite, marcasite, chalcopyrite, galena, argentite, pyrargyrite, and argentian tetrahedrite. Only calcite was deposited during stage II. Fluid inclusions in quartz contain three main types of C–O–H fluids: CO₂-rich, CO₂–H₂O, and aqueous inclusions. Quartz veins related to early sulfides in stage I were deposited from H₂O–NaCl–CO₂ fluids (1,500–5,000 bar, average 3,200) with T _htotal values of 200°C to 383°C and salinities less than about 7 wt.% NaCl equiv. Late sulfide deposition was related to H₂O–NaCl fluids (140–1,300 bar, average 700) with T _htotal values of 110°C to 385°C and salinities less than about 11 wt.% NaCl equiv. These fluids either evolved through immiscibility of H₂O–NaCl–CO₂ fluids as a result of a decrease in fluid pressure, or through mixing with deeply circulated meteoric waters as a result of uplift or unloading during mineralization, or both. Measured and calculated sulfur isotope compositions (δ³⁴S_H2S = 1.5 to 4.8‰) of hydrothermal fluids from the stage I quartz veins indicate that ore sulfur was derived mainly from a magmatic source. The calculated and measured oxygen and hydrogen isotope compositions (δ¹⁸O_H2O = −5.9‰ to 10.9‰, δD = −102‰ to −87‰) of the ore-forming fluids indicate that the fluids were derived from magmatic sources and evolved by mixing with local meteoric water by limited water–rock exchange and by partly degassing in uplift zones during mineralization. While most features of the Samgwang mine are consistent with classification as an orogenic gold deposit, isotopic and fluid chemistry indicate that the veins were genetically related to intrusions emplaced during the Jurassic to Cretaceous Daebo orogeny.  相似文献   

Geotechnical and hydrogeological approaches towards conservation of the Muryong Royal Tomb in Korea   总被引：2，自引：0，他引：2  

Min-Ho Koo  Man-Cheol Suh 《Environmental Geology》2001,41(3-4):470-479

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Instability of an underground ancient tomb due to excavation and its relationship to the temperature and ground water     

Mancheol Suh  Min-Ho Koo  Suck-Won Choi  Insun Song 《Geotechnical and Geological Engineering》2004,22(2):269-283

In order to consider a counterplan to preserve an ancient royal tomb in Kongju, Korea, the deformation of the wall structure, the atmospheric temperature in the tomb, and the groundwater level have been monitored. The long-term measurement of biaxial tilting of the tomb walls revealed that the brick-built subsurface opening had been subjected to severe structural instability. The measured deformation of the tomb was consistent with the displacement of soil around the tomb calculated using a numerical analysis. The instability of the tomb structure is closely related to the rainy season as the deformations measured are several times that in the dry season. A sudden change of temperature inside the tomb exerted an influence on the deformation of the tomb structure as well. It is suggested that the excavation be restored for tourists, the quicklime layer for preventing groundwater infiltration is reinforced, and a constant temperature is kept inside the tomb. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Genetic environment of germanium-bearing gold-silver vein ores from the Wolyu mine,Republic of Korea   总被引：1，自引：0，他引：1  

Seong-Taek Yun  Chil-Sup So  Sang-Hoon Choi  Kevin L. Shelton  Ja-Hak Koo 《Mineralium Deposita》1993,28(2):107-121

The Wolyu mine is one of the largest vein-type gold-silver-bearing epithermal systems in the Youngdong district and is the first gold-silver deposit in Korea found to contain significant germanium, in the form of argyrodite (Ag₈GeS₆). Mineralized veins (78.9 ± 1.2 Ma) crosscutting Late Cretaceous hostrock tuff and quartz porphyry (81.5 ± 1.8 Ma) consist of three stages of quartz and carbonates, the first of which contains pyrite, basemetal sulfides and Au-Ag-minerals. Stage I Au-Ag-Ge-mineralized veins show a systematic variation of mineral assemblage with time: (1) quartz + pyrite; (2) quartz + pyrite + sphalerite + electrum + argentite; (3) carbonate + quartz + sphalerite + electrum + argentite; (4) carbonate + native silver + argentite + Ag-sulfosalts + argyrodite + sphalerite. Calculated values of temperature and sulfur activity are: assemblage (1), 360-280°C and 10^–7-10^–10; (2), 280-210°C and 10^–10-10^–14; (3), 210-180°C and 10^–14-10^–16; (4), 180-155°C and 10^–17-10^–18. These data, the frequent association of gold with sulfides, and the abundance of pyrite in alteration zones indicate that decreasing sulfur activity and cooling were important in triggering gold deposition. Hydrogen and oxygen isotope compositions of ore fluids display a systematic variation with increasing time. Within the main Ag-Au-Ge mineralization, D and ¹⁸O values decrease with the transition from quartz to carbonate deposition (from -78 and –2.8% to –90 and –8.7%., respectively), indicating increasing involvement (mixing) of less evolved meteoric water which resulted in progressive cooling and dilution of ore fluids in the shallow ( 370–600 m) Wolyu epithermal system.  相似文献   

The DEEP2 galaxy redshift survey: evolution of the colour–density relation at  0.4 < z < 1.35      

Michael C. Cooper  Jeffrey A. Newman †  Alison L. Coil †  Darren J. Croton  Brian F. Gerke  Renbin Yan  Marc Davis  S. M. Faber  Puragra Guhathakurta  David C. Koo  Benjamin J. Weiner  Christopher N. A. Willmer ‡ 《Monthly notices of the Royal Astronomical Society》2007,376(4):1445-1459

Using a sample of 19 464 galaxies drawn from the DEEP2 Galaxy Redshift Survey, we study the relationship between galaxy colour and environment at  0.4 < z < 1.35  . We find that the fraction of galaxies on the red sequence depends strongly on local environment out to   z > 1  , being larger in regions of greater galaxy density. At all epochs probed, we also find a small population of red, morphologically early-type galaxies residing in regions of low measured overdensity. The observed correlations between the red fraction and local overdensity are highly significant, with the trend at   z > 1  detected at a greater than 5σ level. Over the entire redshift regime studied, we find that the colour–density relation evolves continuously, with red galaxies more strongly favouring overdense regions at low z relative to their red-sequence counterparts at high redshift. At   z ≳ 1.3  , the red fraction only weakly correlates with overdensity, implying that any colour dependence to the clustering of  ∼ L *  galaxies at that epoch must be small. Our findings add weight to existing evidence that the build-up of galaxies on the red sequence has occurred preferentially in overdense environments (i.e. galaxy groups) at   z ≲ 1.5  . Furthermore, we identify the epoch  ( z ∼ 2)  at which typical  ∼ L *  galaxies began quenching and moved on to the red sequence in significant number. The strength of the observed evolutionary trends at  0 < z < 1.35  suggests that the correlations observed locally, such as the morphology–density and colour–density relations, are the result of environment-driven mechanisms (i.e. 'nurture') and do not appear to have been imprinted (by 'nature') upon the galaxy population during their epoch of formation.  相似文献   

Multisite campaign on the open cluster M67 – III. δ Scuti pulsations in the blue stragglers     

H. Bruntt  D. Stello  J. C. Suárez  T. Arentoft  T. R. Bedding  M. Y. Bouzid  Z. Csubry  T. H. Dall  Z. E. Dind  S. Frandsen  R. L. Gilliland  A. P. Jacob  H. R. Jensen  Y. B. Kang  S.-L. Kim  L. L. Kiss  H. Kjeldsen  J.-R. Koo  J.-A. Lee  C.-U. Lee  J. Nuspl  C. Sterken  R. Szabó 《Monthly notices of the Royal Astronomical Society》2007,378(4):1371-1384

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