• Journal of Korean Society of Forest Science
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• v.83 no.4
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• pp.460-472
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• 1994

This study has been conducted to give some ideas for reasonable ecological management of Taejon city and its adjacent forest ecosystem against the effect of acid rain. Rain monitoring points to analyse its components represented 1 point in industrial area, 4 points in commercial area, 4 points in residential area, and 5 points in suburban area and forest survey was done in 7 forest sites adjacent to rain monitoring points. Transformed vegetation index(TVI) based on Landsat TM data was analysed for forest area. Taejon area was seriously contaminated by air pollutants and average concentration of anions in precipitation were 20.16mg/l for $SO_4{^{2-}}$, 3.65mg/l for $NO_3{^-}$, and 3.09mg/l for $Cl^-$. Anion in precipitation were $1.09mg/m^2/month$ for $SO_4{^{2-}}$, $0.23mg/m^2/month$ for $NO_3{^-}$, and $0.20mg/m^2/month$ for $Cl^-$. Cation in precipitation were $0.14mg/m^2/month$ for $Ca^{2+}$, $0.10mg/m^2/month$ for $NH_4{^+}$, $0.08mg/m^2/month$ for $Na^+$, $0.07mg/m^2/month$ for $K^+$, and $0.08mg/m^2/month$ for $Mg^{2+}$. The region with the highest concentration of $SO_4{^{2-}}$, $NO_3{^-}$, and $Cl^-$ in rain was industrial area. $SO_4{^{2-}}$, $NO_3{^-}$, and $Cl^-$ concentrations in industrial area were 43.08, 3.88, and 3.64ppm, respectively. Forest soil showed strongly acidic ranging pH4.16-4.94. Transformed vegetation index(TVI) were 3.11 in Dangsan, 4.00 in Kyechoksan, 4.13 in Bomunsan, 4.18 in Kabhasan, 3.34 in Bongsan, 4.13 in Sikchangsan, and 4.20 in Seongchisan. Dangsan forest located near in industrial area showed the lowest TVI.

• Journal of the Korean Wood Science and Technology
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• v.42 no.6
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• pp.732-739
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• 2014

This research was performed to investigate the effect of recent climate changes on wood decay hazard index (Scheffer index) in Korea. The index was determined using a climate data of 58 different locations obtained from the website of Korea Meteorological Administration (KMA), and the wood decay hazard index was determined at the intervals of 10 years. Most of regions in Korea except Juju island showed wood decay hazard index values between 35 and 65, considered to be moderate decay hazard zones. But in recent 10 years (2003~2012), the wood decay hazard index was rapidly increased, resulting in showing many high decay hazard regions. The trend may be explained by the in crease of temperature and precipitation. The recent climate change of Korea turning into the weather of subtropical region may explain the increase of wood decay hazard index.

• Journal of Environmental Science International
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• v.25 no.4
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• pp.459-472
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• 2016

We assessed the distribution of benthic macroinvertebrate at four surveying sites in Upo Wetland, a Ramsar site and the largest wetland in Korea, from February 2006 to November 2013. A long-term ecological monitoring was done monthly by using quantitative sampling method with dip net for analyzing the community change and correlation between the biodiversity and the environmental factors because environmental factors have a decisive effect on the community structure of the benthic macroinvertebrates. Total samples from the Upo Wetland area were classified into 3 phyla, 6 classes, 17 orders, 68 families, 176 species, and 25,720 individuals. Among the 176 species, 62 of the species had not been previously reported in this area. Asellus sp., Diplonychus esakii, and Gyraulus chinensis were the most common species in Upo Wetland. The change patterns of annual species diversity and species richness were calculated by using the average number of monthly occurring species and individuals. Diversity index increased from March to May and decreased after that showing lower diversity indices in July and August. It increased again in September and in October. Richness index showed similar tendency and fell around February and July, followed by a rising tendency around May and October. Correlation and regression analyses were performed with the change of biodiversity and each environmental factor. We found that water temperature have very significant positive correlation with species diversity in spring, and have significant indices in autumn and winter. On the other hand, precipitation showed a significantly negative correlation value in summer and autumn suggesting it has an effect on the community structure of benthic macroinvertebrates.

• Journal of Soil and Groundwater Environment
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• v.23 no.3
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• pp.1-9
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• 2018

This study is aimed to quantitatively evaluate the effects of drought on groundwater system in rural areas. For this purpose, the standardized groundwater level index (SGI) was used for 68 groundwater monitoring wells. To determine accumulation period (AP) which represents the month with the highest correlation coefficient between SGI and SPI, correlation analysis between the two for 68 wells were peformed. The results indicated the AP values ranged in 1~3 months for most of the well, but it was 7~10 months in some wells. These results can be interpreted such that the total amount of groundwater will not decrease significantly in long-term drought situations unlikely the reservoirs with the high AP values. The nationwide maximum AP values were 4.1 and 4.0 in Chungbuk-do and Gyeongnam-do, while the minimum AP values were 1.8 and 2.0 in Gangwon-do and Chungnam-do, respectively. The maximum and minimum values of correlation coefficient were 0.623 and 0.459 in Gyeongnam-do and Chungnam-do/Chungbuk-do, respectively. Consequently, it could be concluded that the wells with low AP value tend to respond to short-term drought, but it has little effect on groundwater system when the long drought occurs.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.6
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• pp.509-519
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• 2017

Crop simulation models are valuable tools for estimating crop yield, environmental factors and management practices. The objective of this study was to evaluate the effect of soil types on barley productivity using CERES (Crop Environment REsource Synthesis)-barley, cropping system model. So the behavior of the model under various soil types and climatic conditions was evaluated. The results of the sensitivity analysis in temperature, $CO_2$, and precipitation showed that soil types had a direct impact on the simulated yield of CERES-barley model. We found that barley yield in clay soils would be more sensitive to precipitation and $CO_2$ in comparison with temperature. And the model showed limited accuracy in simulating water and nitrogen stress index for soil types. In general, the barley grown on clay soils were less sensitive to water stress than those grown on sandy soils. Especially it was found that the CERES model underestimated the effect of water stress in high precipitation which led to overprediction of crop yield in clay soils. In order to solve these problems and successfully forecast grain yield, further studies on the modification of the water stress response of crops should be considered prior to use of the CERES-barley model for yield forecasting.

• Korean Journal of Environment and Ecology
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• v.29 no.6
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• pp.917-922
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• 2015

This study was carried out to investigate solutes concentration change with respect to discharge change in coniferous forest experiment watershed in Gyeonggi-do, Korea. From 2005 to 2008. Precipitation, discharge, solutes has been analyzed from 23 precipitation events. The results showed that low API induced low discharge. $NH_4{^+}$, $K^+$, and $Ca^{2+}$ were indicated by clockwise and $Cl^-$ and $NO_3{^-}$ were represented by counterclockwise hysteresis loop. ${SO_4}^{2-}$, $Na^+$, $Mg^{2+}$ showed no hysteresis loop pattern. $Cl^-$, $Na^+$, $NH_4{^+}$ was relatively constant due to groundwater during precipitation, $NO_3{^-}$ was increased due to soil water compared to early precipitation. $Cl^-$, ${SO_4}^{2-}$, $Na^+$, $Mg^{2+}$, $Ca^{2+}$ was diluted with respect to increased discharge and $NO_3{^-}$ was diluted in early precipitation and then increased in the end. $NO_3{^-}$ and $Ca^{2+}$ eluviated in early precipitation. This characteristics was presumed by the effect of API, discharge and ground water.

• Journal of Korean Society of Forest Science
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• v.77 no.2
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• pp.216-222
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• 1988

This study was conducted to investigate the effect of meteorological factors on the diameter growth and Key-year in Pinus koraiensis and Pinus densiflora trees grown in Chuncheon and Hongcheon. The results obtained were summarized as follows : 1. The diameter growth of Pinus koraiensis was better than that of Pinus densiflora grown in the same meteorological condition and site environment. 2. The influence of meteorological factors on the diameter growth of Pinus koraiensis was the highest in the descending order fog, hours of sunshine, precipitation, relative humidity, warm index, and evaporation. 3. The influence of meteorological factors on the diameter growth of Pinus densiflora was the highest in the descending order fog, hours of sunshine, relative humidity, precipitation, and warm index. But evaporation was not significant. 4. The Key-years for Pinus koraiensis and Pinus densiflora trees appeared in 1964 and 1913 when the diameter growth was influenced by the specific climate change.

• Economic and Environmental Geology
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• v.33 no.1
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• pp.31-40
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• 2000

Sorption characteristics of Pb, Cu, Cd, and Zn onto Ca- and Na-bentonites were investigated by the batch experiments in the condition of various pHs and concentrations of groundwater major anions (${So_4}^{2-}$ and ($HCO_3$), which can form a complex with heavy metals. The sorption removal of heavy metals steadily increases as pH increases. The sorption capability about heavy metals of both Ca-bentonite and Na-bentonite is in the order of Pb>Cu>Zn>Cd. The effect of pH and selectivity of heavy metals of bentonites were explained by the change of surface charge of bentonite and the speciation of heavy metals. Na-bentonite has a little higher sorption ability about heavy metals than that of Ca-bentonite. A high sorption removal of Pb in 0.1M sulfate solution may be attributed to the precipitation of $PbSo_4$(anglesite). However, sulfate has a slight effect on the sorption of CU, Cd and Zn. More than 99% of heavy metals were removed from the 0.1 M bicarbonate solution. However, the efficiency of sorption removal of heavy metals highly decreases in the bicarbonate solution of $10^{-2}$M to $10^{-4}$M. The speciation and saturation index calculated by the WATEQ4F program indicate that the sorption of anionic complexes such as ${Pb(CO_3)_2}^{2-}$, ${Cd(CO_3)_2}^{2-}$, ${Zn(CO_3)_2}^{2-}$, ${Cu(CO_3)_2}^{2-}$ and the precipitation of the solid phases such as $PbCO_3$(cerrusite), $ZnCO_3$(smithsonite), $CdCO_3$(obtavite) are involved in sorption removal of heavy metals in bicarbonate solution. The sorption capability about heavy metals of bentonites in the presence of anions shows the following order: Pb>Cu Cd>Zn.

• Journal of Korea Water Resources Association
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• v.49 no.4
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• pp.293-303
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• 2016

This study implemented a comparison of SPI characteristics in terms of quantitative and spatial analysis depending on four RCP scenarios. For this purpose, we compared quantitative characteristics of drought using standard precipitation index resulted from daily precipitation data reflecting future green gas concentration scenarios, and spatial distribution field of seasonal drought occurrence frequency and its duration, was analyzed to compare drought trends depending on the RCP scenarios. As a result, we found that SPI time series was quite different from each other and correlation coefficients were lower than 0.08. Depending on the RCP scenarios, spatial distribution results showed different trends in drought severity, frequency, and duration. The biggest reason of the difference is daily precipitation data based on the different greenhouse gas concentrations, but we could not find the effect of the concentration extent on drought occurrence projection. In addition, according to the results from this study, drought analysis results using single RCP scenario may have considerable uncertainty.

• Korean Journal of Remote Sensing
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• v.34 no.1
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• pp.25-43
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• 2018

The effects of hydro-meteorological and surface variables on the frequency of Asian dust events (FAE) were investigated using ground station and satellite-based data. Present weather codes 7, 8, and 9 derived from surface synoptic observations (SYNOP)were used for counting FAE. Surface wind speed (SWS), air temperature (Ta), relative humidity (RH), and precipitation were analyzed as hydro-meteorological variables for FAE. The Normalized Difference Vegetation Index (NDVI), land surface temperature (LST), and snow cover fraction (SCF) were used to consider the effects of surface variables on FAE. The relationships between FAE and hydro-meteorological variables were analyzed using Z-score and empirical orthogonal function (EOF) analysis. Although all variables expressed the change of FAE, the degrees of expression were different. SWS, LST, and Ta (indices applicable when Z-score was < 0) explained about 63.01, 58.00, and 56.17% of the FAE,respectively. For NDVI, precipitation, and RH, Asian dust events occurred with a frequency of about 55.38, 67.37, and 62.87% when the Z-scores were > 0. EOF analysis for the FAE showed the seasonal cycle, change pattern, and surface influences related to dryness condition for the FAE. The intensity of SWS was the main cause for change of FAE, but surface variables such as LST, SCF, and NDVI also were expressed because wet surface conditions suppress FAE. These results demonstrate that not only SWS and precipitation, but also surface variables, are important and useful precursors for monitoring Asian dust events.