Salinization properties of a shallow groundwater in a coastal reclaimed area,Yeonggwang, Korea     

Rak-Hyeon Kim  Ji-Hoon Kim  Jong-Sik Ryu  Ho-Wan Chang 《Environmental Geology》2006,49(8):1180-1194

The need for more agricultural or residential land has encouraged reclamation at the coastal areas of Korea since 1200 ad (approximately). The groundwaters of these reclaimed areas could be expected to reveal hydrogeochemical properties different from those of areas directly affected by seawater intrusion. The purpose of this study, therefore, was to examine the salinization of shallow groundwater in a coastal reclaimed area and to identify the effect of land reclamation on groundwater quality. Major cations and anions, iodide, total organic carbon, δD, δ ¹⁸O and δ ¹³C were measured to assist the hydrogeochemical analysis. Chloride, δD and δ ¹⁸O data clearly show that the Na–Cl type water results from mixing of groundwater with seawater. In particular, the δD and δ ¹⁸O of Ca+Mg–Cl+NO₃ type groundwaters are close to the meteoric water line, but Na–Cl type waters enriched in chloride are ¹⁸O-enriched with respect to the meteoric water line. Meanwhile, carbon isotopic data and I/Cl ratios strongly suggest that there are various sources of salinity. The δ ¹³C values of Na–Cl type groundwaters are generally similar to those of Ca+Mg–Cl+NO₃ type waters, which are depleted in ¹³C with respect to seawater. I/Cl ratios of Na–Cl type groundwater are 10–100 times higher than that of seawater. Because the reclamation has incorporated a large amount of organic matter, it provides optimum conditions for the occurrence of redox processes in the groundwater system. Therefore, the salinization of groundwater in the study area seems to be controlled not only by saltwater intrusion but also by other effects, such as those caused by residual salts and organic matter in the reclaimed sediments.  相似文献   

Tephrostratigraphy and paleoenvironmental variation in late Quaternary core sediments of the southwestern Ulleung Basin, East Sea (Sea of Japan)     

Il-Soo  Kim  Myong-Ho  Park  Byong-Jae  Ryu Kang-Min  Yu 《Island Arc》2006,15(1):178-186

Abstract   Data on the late Quaternary tephra layers, tephrostratigraphy, geochemistry and environment were determined in two sediment cores from the southwestern part of Ulleung Basin (East Sea/Sea of Japan), representing marine-oxygen isotope stages 1–3. The cores consist mainly of muddy sediments that are partly interbedded with silty sands, lapilli tephra and ash layers. The lapilli tephra layers (Ulleung-Oki tephra, 9.3 ka) originating from Ulleung Island consist mainly of massive-type glass shards, whereas the ash layers (Aira-Tanzawa ash, 22.0–24.7 ka) derived from southern Kyushu Island are mainly composed of typical plane-type and bubble-wall glasses that are higher in SiO₂ and lower in Na₂O + K₂O than the lapilli tephra layers. Except for the tephra layers, fine-grained sediments throughout the core sections are mostly of marine origin based on geochemical data (C/N ratios, hydrogen index, S2 peak) and Tmax. In particular, organic carbon contents increased during Termination I, probably as a result of an influx of the deglacial Tsushima Current through the Korea Strait.  相似文献   

Seasonally Varying Reference Atmospheres for East Asia     

Byung-Ju SOHN  Geun-Hyeok RYU 《大气科学进展》2007,24(2):181-190

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Removal of lead(II) from aqueous stream by hydrophilic modified kapok fiber using the Fenton reaction     

Dongfang Wang  Daeik Kim  Chul-Ho Shin  Yufeng Zhao  Joon-Seok Park  Moonhee Ryu 《Environmental Earth Sciences》2018,77(18):653

A hydrophilic kapok fiber was prepared by a chemical process of the Fenton reaction and used as an adsorbent to remove Pb(II) from aqueous solution. The effects of experimental parameters including pH, contact time, Pb(II) concentration, and coexisting heavy metals were estimated as well as evaluated. The optimum concentrations of FeSO₄ and H₂O₂ for the Fenton reaction-modified kapok fiber (FRKF) were 0.5 mol L^?1 and 1 mol L^?1, respectively. The adsorption kinetic models and isotherm equations of Langmuir and Freundlich were conducted to identify the most optimum adsorption rate and adsorption capacity of Pb(II) on FRKF. The FRKF displayed an excellent adsorption rate for Pb(II) in single metal solution with the maximum adsorption capacity of 94.41?±?7.56 mg g^?1 at pH 6.0. Moreover, the FRKE still maintained its adsorption advantage of Pb(II) in the mixed metal solution. The FRKF exhibited a considerable potential in removal of metal content in wastewater streams.  相似文献   

A numerical study of the interactions of urban breeze circulation with mountain slope winds     

Gantuya Ganbat  Jong-Jin Baik  Young-Hee Ryu 《Theoretical and Applied Climatology》2015,120(1-2):123-135

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Development of the Operational Oceanographic System of Korea     

Park  Kwang-Soon  Heo  Ki-Young  Jun  Kicheon  Kwon  Jae-Il  Kim  Jinah  Choi  Jin-Yong  Cho  Kyoung-Ho  Choi  Byoung-Ju  Seo  Seung-Nam  Kim  Young Ho  Kim  Sung-Dae  Yang  Chan-Su  Lee  Jong-Chan  Kim  Sang-Ik  Kim  Seonjeong  Choi  Jung-Woon  Jeong  Sang-Hun 《Ocean Science Journal》2015,50(2):353-369

Ocean Science Journal - The Korea Operational Oceanographic System (KOOS) was developed at the Korea Institute of Ocean Science and Technology (KIOST) to produce real-time forecasting and...  相似文献   

Experimental investigation of dry density effects on dielectric properties of soil–water mixtures with different specific surface areas     

Orangi  A.  Narsilio  G. A.  Wang  Y. H.  Ryu  D. 《Acta Geotechnica》2020,15(5):1153-1172

The dielectric constant of soil is used to estimate its water content in a range of applications. Unlike the widely known effect of water content on the soil dielectric constant (consistent direct proportionality), only a limited number of studies have reported the effects of soil dry density, however, with equivocal results. This paper, therefore, investigates the effects of dry density or degree of compaction on the dielectric constant of five different soil types. The results of the experimental work for the soils ranging from sand to Bentonite clay with distinct specific surface areas were evaluated based on the use of two simple mixture models (De Loor and Birchak). The effects of dry density on the soil dielectric constant were found to be soil type dependent. This is demonstrated by the experimental data and further proven by the modified De Loor model. The behavior is shown to be defined by the changes in the free water, bound water, and solid particle volume fractions, ultimately controlled by the soil specific surface area. The dielectric constant changes from being directly proportional to dry density to inversely proportional at a threshold specific surface area of between 122 and 147 m²/g. Supported by the experimental observations, parametric analysis has revealed that the range for the dielectric constant of bound water was found to be 9–37, while the geometrical parameter α in the Birchak model was found to be 0.4–0.8.

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Diversity and Assemblage Structure of Marine Fish Species Collected by Set Net in Korean Peninsula During 2009–2013     

Ryu  Jung-Hwa  Kim  Jin-Koo 《Ocean Science Journal》2020,55(4):581-591

Ocean Science Journal - Assemblage structure analysis was conducted based on seasonal fish species composition data collected four times a year during 2009–2013 from 10 stations around Korea...  相似文献   

Improved Chlorophyll-a Algorithm for the Satellite Ocean Color Data in the Northern Bering Sea and Southern Chukchi Sea     

Sang Heon Lee  Jongseong Ryu  Jung-woo Park  Dabin Lee  Jae-Il Kwon  Jingping Zhao  SeungHyun Son 《Ocean Science Journal》2018,53(3):475-485

The Bering and Chukchi seas are an important conduit to the Arctic Ocean and are reported to be one of the most productive regions in the world’s oceans in terms of high primary productivity that sustains large numbers of fishes, marine mammals, and sea birds as well as benthic animals. Climate-induced changes in primary production and production at higher trophic levels also have been observed in the northern Bering and Chukchi seas. Satellite ocean color observations could enable the monitoring of relatively long term patterns in chlorophyll-a (Chl-a) concentrations that would serve as an indicator of phytoplankton biomass. The performance of existing global and regional Chl-a algorithms for satellite ocean color data was investigated in the northeastern Bering Sea and southern Chukchi Sea using in situ optical measurements from the Healy 2007 cruise. The model-derived Chl-a data using the previous Chl-a algorithms present striking uncertainties regarding Chl-a concentrations – for example, overestimation in lower Chl-a concentrations or systematic overestimation in the northeastern Bering Sea and southern Chukchi Sea. Accordingly, a simple two band ratio (R_rs(443)/R_rs(555)) algorithm of Chl-a for the satellite ocean color data was devised for the northeastern Bering Sea and southern Chukchi Sea. The MODIS-derived Chl-a data from July 2002 to December 2014 were produced using the new Chl-a algorithm to investigate the seasonal and interannual variations of Chl-a in the northern Bering Sea and the southern Chukchi Sea. The seasonal distribution of Chl-a shows that the highest (spring bloom) Chl-a concentrations are in May and the lowest are in July in the overall area. Chl-a concentrations relatively decreased in June, particularly in the open ocean waters of the Bering Sea. The Chl-a concentrations start to increase again in August and become quite high in September. In October, Chl-a concentrations decreased in the western area of the Study area and the Alaskan coastal waters. Strong interannual variations are shown in Chl-a concentrations in all areas. There is a slightly increasing trend in Chl-a concentrations in the northern Bering Strait (SECS). This increasing trend may be related to recent increases in the extent and duration of open waters due to the early break up of sea ice and the late formation of sea ice in the Chukchi Sea.  相似文献   

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