Arsenic contamination in agricultural soils surrounding mining sites in relation to geology and mineralization types     

Ji Cheol Kwon  Jin-Soo Lee  Myung Chae Jung 《Applied Geochemistry》2012

A national-scale survey of the environment in and around mines was conducted to evaluate the status of total As contamination in agricultural soils surrounding numerous abandoned metal mines in Korea. This survey aimed to compare As concentrations in soils in relation to geology and mineralization types of mines. A total of 16,386 surface soil (0–15 cm in depth) samples were taken from agricultural lands near 343 abandoned mines (within 2 km of each mine). These samples were decomposed by aqua regia and analyzed for As by AAS with a hydride-generation (HG) device. To compare As levels in soils meaningfully with geology and mineralization types, three sub-classification criteria were adapted: (1) five mineralization types, (2) four valuable ore mineral types, and (3) four parent rock types. The average concentration of As in all the soils was 11.6 mg kg⁻¹ with a range of 0.01–4230 mg kg⁻¹. Based on the mineralization types, average As concentrations (mg kg⁻¹) in the soils decreased in the order of pegmatite (18.2) > hydrothermal replacement (14.5) > sedimentary deposits (12.4) > hydrothermal vein (10.7) > skarn (4.08). In terms of the valuable ore mineral types, the concentrations decreased in the order of Sn, W, Mo, Fe and Mn mines > Au, Ag, and base metal mines > Au and Ag mines ≈ base metal mines. For parent rock types, soils from metamorphic rocks and heterogeneous rocks exhibited enhanced As levels related to both igneous and sedimentary rocks. Therefore, it can be concluded that soils from highly altered rocks subject to metamorphic and igneous activities contained relatively high concentrations of As in the surface environment.  相似文献   

Closure to Discussion of paper ‘Evaluation of building period formulas for seismic design’ by Oh‐Sung Kwon and Eung Soo Kim,Earthquake Engineering and Structural Dynamics 2010; 39(14):1569–1583     

Oh‐Sung Kwon  Eung Soo Kim 《地震工程与结构动力学》2012,41(6):1133-1135

  相似文献   

Simulation of daily rainfall scenarios with interannual and multidecadal climate cycles for South Florida   总被引：4，自引：3，他引：1  

Hyun-Han Kwon  Upmanu Lall  Jayantha Obeysekera 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(7):879-896

Concerns about the potential effects of anthropogenic climate change have led to a closer examination of how climate varies in the long run, and how such variations may impact rainfall variations at daily to seasonal time scales. For South Florida in particular, the influences of the low-frequency climate phenomena, such as the El Nino Southern Oscillation (ENSO) and the Atlantic Multi-decadal Oscillation (AMO), have been identified with aggregate annual or seasonal rainfall variations. Since the combined effect of these variations is manifest as persistent multi-year variations in rainfall, the question of modeling these variations at the time and space scales relevant for use with the daily time step-driven hydrologic models in use by the South Florida Water Management District (SFWMD) has arisen. To address this problem, a general methodology for the hierarchical modeling of low- and high-frequency phenomenon at multiple rain gauge locations is developed and illustrated. The essential strategy is to use long-term proxies for regional climate to first develop stochastic scenarios for regional climate that include the low-frequency variations driving the regional rainfall process, and then to use these indicators to condition the concurrent simulation of daily rainfall at all rain gauges under consideration. A newly developed methodology, called Wavelet Autoregressive Modeling (WARM), is used in the first step after suitable climate proxies for regional rainfall are identified. These proxies typically have data available for a century to four centuries so that long-term quasi-periodic climate modes of interest can be identified more reliably. Correlation analyses with seasonal rainfall in the region are used to identify the specific proxies considered as candidates for subsequent conditioning of daily rainfall attributes using a Non-homogeneous hidden Markov model (NHMM). The combined strategy is illustrated for the May–June–July (MJJ) season. The details of the modeling methods and results for the MJJ season are presented in this study.  相似文献   

Deformation in and Around Southeast Korea in Relation to the Opening of the East Sea (Sea of Japan)     

Pom-yong Choi  Jae-ha Hwang  Kwan-soon Park  Seok-ki Kwon 《Gondwana Research》1999,2(4):537-540

  相似文献   

Application of hybrid‐simulation to fragility assessment of the telescoping self‐centering energy dissipative bracing system          下载免费PDF全文

Viswanath Kammula  Jeffrey Erochko  Oh‐Sung Kwon  Constantin Christopoulos 《地震工程与结构动力学》2014,43(6):811-830

Substructure hybrid simulation has been the subject of numerous investigations in recent years. The simulation method allows for the assessment of the seismic performance of structures by representing critical components with physical specimens and the rest of the structure with numerical models. In this study the system level performance of a six‐storey structure with telescoping self‐centering energy dissipative (T‐SCED) braces is validated through pseudo‐dynamic (PsD) hybrid simulation. Fragility curves are derived for the T‐SCED system. This paper presents the configuration of the hybrid simulation, the newly developed control software for PsD hybrid simulation, which can integrate generic hydraulic actuators into PsD hybrid simulation, and the seismic performance of a structure equipped with T‐SCED braces. The experimental results show that the six‐storey structure with T‐SCED braces satisfies performance limits specified in ASCE 41. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Potential increase of flood hazards in Korea due to global warming from a high-resolution regional climate simulation   总被引：1，自引：0，他引：1  

Eun-Soon Im  Byong-Ju Lee  Ji-Hye Kwon  So-Ra In  Sang-Ok Han 《Asia-Pacific Journal of Atmospheric Sciences》2012,48(1):107-113

Because of the importance of the changes in the hydrologic cycle, accurate assessment of precipitation characteristics is essential to understand the impact of climate change due to global warming. This study investigates the changes in extreme precipitation with sub-daily and daily temporal scales. For a fine-scale climate change projection focusing on the Korean peninsula (20 km), we performed the dynamical downscaling of the global climate scenario covering the period 1971?C2100 (130-year) simulated by the Max-Planck-Institute global climate model, ECHAM5, using the latest version of the International Centre for Theoretical Physics (ICTP) regional climate model, RegCM3. While annual mean precipitation exhibits a pronounced interannual and interdecadal variability, with the increasing or decreasing trend repeated during a certain period, extreme precipitation with sub-daily and daily temporal scales estimated from the generalized extreme value distribution shows consistently increasing pattern. The return period of extreme precipitation is significantly reduced despite the decreased annual mean precipitation at the end of 21^st century. The decreased relatively weak precipitation is responsible for the decreased total precipitation, so that the decreased total precipitation does not necessarily mean less heavy precipitation. Climate change projection based on the ECHAM5-RegCM3 model chain clearly shows the effect of global warming in increasing the intensity and frequency of extreme precipitation, even without significantly increased total precipitation, which implies an increased risk for flood hazards.  相似文献   

Effects of freshwater runoff on a tropical pacific climate in the HadGEM2     

Suryun Ham  Song-You Hong  Yign Noh  Soon-Il An  Young-Hwa Byun  Hyun-Suk Kang  Johan Lee  Won-Tae Kwon 《Asia-Pacific Journal of Atmospheric Sciences》2012,48(4):457-463

This paper investigates the effects of river discharge on simulated climatology from 1979 to 1988 using the Hadley Centre Global Environmental Model version 2. Two experiments are performed with and without the inclusion of Total Runoff Integrating Pathways. The results show that the inclusion of flow routing can lead to the decrease of salinity over the coastal region due to freshwater. This reduction results in a shallower mixed layer depth, which in turn leads to the weakening of trade winds and a decrease in vertical mixing in the ocean. The enhanced sensible and latent heat fluxes over warmed SST improve the simulated precipitation and thermodynamic circulation. As a result, the experiment with flow routing is capable of improving the large-scale climate feature with an increase in precipitation over the eastern tropical equatorial Pacific region.  相似文献   

A land data assimilation system using the MODIS-derived land data and its application to numerical weather prediction in East Asia   总被引：1，自引：0，他引：1  

Yoon-Jin Lim  Kun-Young Byun  Tae-Young Lee  Hyojung Kwon  Jinkyu Hong  Joon Kim 《Asia-Pacific Journal of Atmospheric Sciences》2012,48(1):83-95

Land Data Assimilation Systems have been developed to generate the surface initial conditions such as soil moisture and temperature for better prediction of weather and climate. We have constructed Korea Land Data Assimilation System (KLDAS) based on an uncoupled land surface modeling framework that integrates high-resolution in-situ observation, satellite data, land surface information from the WRF Preprocessing System (WPS) and the MODIS land products over the East Asia. To present better surface conditions, the KLDAS is driven by atmospheric forcing data from the in-situ rainfall gauges and satellite. In this study, we 1) briefly introduce the KLDAS, 2) evaluate the meteorological states near the surface and the surface fluxes reproduced by the KLDAS against the in-situ observation, and then 3) examine the performance of the mesoscale model initialized by the KLDAS. We have generated a 5-year, 10 km, hourly atmospheric forcing dataset for use in KLDAS operating across East Asia. The KLDAS has effectively reproduced the observed patterns of soil moisture, soil temperature, and surface fluxes. Further scrutiny reveals that the numerical simulations incorporating the KLDAS outputs show better agreement in both the simulated near-surface conditions and rainfall distribution over the Korean Peninsula, compared to those without the KLDAS.  相似文献   

Static pullout resistance of anchor chains in cohesionless soil—laboratory testing     

Byeongwan Kim  Osoon Kwon  BooHyun Nam 《Marine Georesources & Geotechnology》2017,35(6):780-787

This paper investigates the static pullout resistance of anchor chains embedded into cohesionless soil. The anchor chains, which are made of steel, were buried into Jumunjin sand whose relative density was set to approximately 60%. The anchor chains were horizontally pulled out through a displacement of 70?mm in laboratory model tests. Three different embedment depths and seven different numbers of chain links were adopted. The pullout resistance of the anchor chains was found to increase with increasing embedment depth and the number of anchor chain links. The measured resistance was significantly higher than the calculated frictional resistance, implying that the passive resistance at the front of the anchor chain significantly contributes to the pullout resistance. The contribution of the passive resistance tends to decrease with increasing number of chain links.  相似文献   

A time‐domain seismic SSI analysis method for inelastic bridge structures through the use of a frequency‐dependent lumped parameter model          下载免费PDF全文

Nikolaos Lesgidis  Oh‐Sung Kwon  Anastasios Sextos 《地震工程与结构动力学》2015,44(13):2137-2156

It is highlighted in the past that the soil–structure interaction phenomenon can produce a significant alteration on the response of a bridge structure. A variety of approaches has been developed in the past, which is capable of tackling the soil–structure interaction problem from different perspectives. The popular approach of a discretized truncated finite element model of the soil domain is not always a numerically viable solution, especially for computationally demanding simulations such as the probabilistic fragility analysis of a bridge structure or the real time hybrid simulation. This paper aims to develop a complete modeling procedure that is capable of coping with the soil–structure interaction problem of inelastic bridge structures through the use of a frequency dependent lumped parameter assembly. The proposed procedure encounters accuracy and global stability issues observed on past methods while maintaining the broad applicability of the method by any commercial FEM software. A case study of an overpass bridge structure under earthquake excitations is illustrated in order to verify the proposed method. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献