• Journal of the Korean Geophysical Society
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• v.9 no.2
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• pp.135-145
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• 2006

The surface temperature and hydrological budget for the last glacial maximum (LGM) is simulatedwith an atmospheric general circulation model of NCAR CCM3 at spectral truncation of T170, corespondingto a grid cel size of roughly 75 km. LGM simulations were forced with the reconstructed CLIMAP sea surface temperatures, sea ice distribution, ice sheet topography, reduced CO2, and orbital parameters.oC in winter, 5.6oC in sumer,and 6oC annual-mean. The decrease of surface temperature leads to a weakening of the hydrologicalcycle. Global-mean precipitation decreases by about 14% in winter, 17% in summer, and 13% annually.However, some regions such as the U.S., southern Europe, northern and eastern Africa, and the SouthAmerica appear to be weter in the LGM winter and Canada and the Midle East are weter in sumer. model captures detailed climate features over land.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.2 no.4
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• pp.219-228
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• 2021

During our observations of changes in halophyte distribution in Hampyeong Bay over a period of five years, we found that the distribution area showed a maintenance for Phragmites communis community, a tendency of gradual increase for Zoysia sinica community, gradual decrease for Suaeda maritima community, and disappearance for Limonium tetragonum community during the studied period. The Phragmites communis community stably settled in areas adjacent to land and appeared not to be significantly affected by physical factors (such as tides and waves) or disturbances caused by biological factors (such as interspecific competition). Among studied species, germination time was shown to be the fastest for Suaeda maritima. In addition, this species showed certain characteristics that allowed it to settle primarily in new habitats formed by sand deposition as its growth was not halted under conditions with high amounts of sand and high organic matter content. However, in areas where Zoysia sinica and Suaeda maritima resided together, the area inhabited by Suaeda maritima gradually decreased due to interspecific competition between the two species. This was believed to be the result of a sharp decrease in the germination of Suaeda maritima since May, while the germination of Zoysia sinica was continuously maintained, indicating that the latter had an advantage in terms of seedling competition. In the case of the Limonium tetragonum community, its habitat was found to have been completely destroyed because it was covered by sand. The study area was confirmed to have undergone a large change in topography as tides and waves resulted in sand deposition onto these lands. Hampyeong Bay is considered to have experienced changes in halophyte distribution related to certain complex factors, such as changes in physical habitats and changes in biological factors such as interspecific competition.

• Journal of Soil and Groundwater Environment
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• v.26 no.6
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• pp.47-64
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• 2021

In this study, the annual and monthly groundwater recharge for the Sapgyo-cheon upstream basin in Chungnam Province was evaluated by water balance analysis utilizing WetSpass-M model. The modeling input data such as topography, climate parameters, LAI (Leaf Area Index), land use, and soil characteristics were established using ArcGIS, QGIS, and Python programs. The results showed that the annual average groundwater recharge in 2001 - 2020 was 251 mm, while the monthly groundwater recharge significantly varied over time, fluctuating between 1 and 47 mm. The variation was high in summer, and relatively low in winter. Variation in groundwater recharge was the largest in July in which precipitation was heavily concentrated, and the variation was closely associated with several factors including the total amount of precipitation, the number of days of the precipitation, and the daily average precipitation. This suggests the extent of groundwater recharge is greatly influenced not only by quantity of precipitation but also the precipitation pattern. Since climate condition has a profound effect on the monthly groundwater recharge, evaluation of monthly groundwater recharge need to be carried out by considering both seasonal and regional variability for better groundwater usage and management. In addition, the mathematical tools for groundwater recharge analysis need to be improved for more accurate prediction of groundwater recharge.

• Korean Journal of Ecology and Environment
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• v.53 no.4
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• pp.408-426
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• 2020

This study aims to establish the national strategy for biodiversity conservation by analyzing the current status of ecodiversity as the foundation of biodiversity conservation. Furthermore, this study has another purpose of preparing the measures for conservation and restoration of biodiversity. Ecodiversity was discussed as the basis for conserving biodiversity. Five climate zones and 14 climatic regions, eight plant geographic regions, three massifs and major geologic series, horizontal and vertical topographic conditions, 16 ecoregions, major ecosystems including forest, river and streams, wetlands, coast and marine, agriculture, and urban esosystems, and land use types were discussed as the element of the ecodiversity. In terms of biodiversity conservation, the actual conditions of each ecological unit were reviewed and measures were proposed to reduce biodiversity loss. Destruction and fragmentation of habitat, poor ecosystem management due to socioeconomic changes, the effects of exotic species and chemicals, and climate change were discussed as the major factors causing biodiversity loss. Systematic monitoring based on scientific principles and ecological restoration based on those monitoring results were recommended as measures for biodiversity conservation.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.25 no.3
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• pp.29-45
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• 2022

For biodiversity conservation, the importance of beta-diversity which is changes in the composition of species according to environmental changes has become emphasized. However, given the systematic investigation of species distribution and the accumulation of large amounts of data in the Republic of Korea(ROK), research on the spatialization of beta-diversity using them is insufficient. Accordingly, this research investigated the applicability of the Generalized Dissimilarity Modeling(GDM) to ROK, which can predict and map the similarity of compositional turnover (beta-diversity) based on environmental variables. A brief overview of the statistical description on using GDM was presented, and a model was fitted using the flora distribution data(410,621points) from the National Ecosystem Survey and various environmental spatial data including climate, soil, topography, and land cover. Procedures and appropriated spatial units required to improve the explanatory power of the model were presented. As a result, it was found that geographical distance, temperature annual range, summer temperature, winter precipitation, and soil factors affect the dissimilarity of the vegetation community composition. In addition, as a result of predicting the similarity of vegetation composition across the nation, and classifying them into 20 and 100 zones, the similarity was high mainly in the central inland area, and tends to decrease toward the mountainous areas, southern coastal regions, and island including Jeju island, which means the composition of the vegetation community is unique and beta diversity is high. In addition, it was identified that the number of common species between zones decreased as the geographic distance between zones increased. It classified the spatial distribution of plant community composition in a quantitative and objective way, but additional research and verification are needed for practical application. It is expected that research on community-level biodiversity modeling in the ROK will be conducted more actively based on this study.

• Journal of the Korean Institute of Rural Architecture
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• v.23 no.4
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• pp.1-12
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• 2021

Recently, the use of unmanned aerial vehicles (UAVs) is increasing in the field of land information acquisition and terrain exploration through high-altitude aerial photography. High-altitude aerial photography is suitable for large-scale geographic information collection, but has the disadvantage that it is difficult to accurately collect small-scale geographic information. Therefore, this study used low-altitude UAV to monitor changes in small rural spaces around rural resources, and the results are as follows. First, the low-altitude aerial imagery had a very high spatial resolution, so it was effective in reading and analyzing topographic features. Second, an area with a large number of aerial images and a complex topography had a large amount of point clouds to be extracted, and the number of point clouds affects the three-dimensional quality of rural space. Third, 3D mapping technology using point cloud is effective for monitoring rural space and rural resources because it enables observation and comparison of parts that cannot be read from general aerial images. In this study, the possibility of rural space analysis of low-altitude UAV was verified through aerial photography and analysis, and the effect of 3D mapping on rural space monitoring was visually analyzed. If data acquired by low-altitude UAV are used in various forms such as GIS analysis and topographic map production it is expected to be used as basic data for rural planning to maintain and preserve the rural environment.

• Journal of Radiation Protection and Research
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• v.48 no.1
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• pp.28-43
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• 2023

Background: High-fidelity meteorological data is a prerequisite for the realistic simulation of atmospheric dispersion of radioactive materials near nuclear power plants (NPPs). However, many meteorological models frequently overestimate near-surface wind speeds, failing to represent local meteorological conditions near NPPs. This study presents a new high-resolution (approximately 1 km) meteorological downscaling method for modeling short-range (< 100 km) atmospheric dispersion of accidental NPP plumes. Materials and Methods: Six considerations from literature reviews have been suggested for a new dynamic downscaling method. The dynamic downscaling method is developed based on the Weather Research and Forecasting (WRF) model version 3.6.1, applying high-resolution land-use and topography data. In addition, a new subgrid-scale topographic drag parameterization has been implemented for a realistic representation of the atmospheric surface-layer momentum transfer. Finally, a year-long simulation for the Kori and Wolsong NPPs, located in southeastern coastal areas, has been made for 2016 and evaluated against operational surface meteorological measurements and the NPPs' on-site weather stations. Results and Discussion: The new dynamic downscaling method can represent multiscale atmospheric motions from the synoptic to the boundary-layer scales and produce three-dimensional local meteorological fields near the NPPs with a 1.2 km grid resolution. Comparing the year-long simulation against the measurements showed a salient improvement in simulating near-surface wind fields by reducing the root mean square error of approximately 1 m/s. Furthermore, the improved wind field simulation led to a better agreement in the Eulerian estimate of the local atmospheric dispersion. The new subgrid-scale topographic drag parameterization was essential for improved performance, suggesting the importance of the subgrid-scale momentum interactions in the atmospheric surface layer. Conclusion: A new dynamic downscaling method has been developed to produce high-resolution local meteorological fields around the Kori and Wolsong NPPs, which can be used in short-range atmospheric dispersion modeling near the NPPs.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.2
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• pp.113-119
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• 1998

Spatial patterns of soil temperature on sloping lands are related to the amount of solar irradiance at the surface. Since soil temperature is a critical determinant of many biological processes occurring in the soil, an accurate prediction of soil temperature distribution could be beneficial to agricultural and environmental management. However, at least two problems are identified in soil temperature prediction over natural sloped surfaces. One is the complexity of converting solar irradiances to corresponding soil temperatures, and the other, if the first problem could be solved, is the difficulty in handling large volumes of geo-spatial data. Recent developments in geographic information systems (GIS) provide the opportunity and tools to spatially organize and effectively manage data for modeling. In this paper, a simple model for conversion of solar irradiance to soil temperature is developed within a GIS environment. The irradiance-temperature conversion model is based on a geophysical variable consisting of daily short- and long-wave radiation components calculated for any slope. The short-wave component is scaled to accommodate a simplified surface energy balance expression. Linear regression equations are derived for 10 and 50 cm soil temperatures by using this variable as a single determinant and based on a long term observation data set from a horizontal location. Extendability of these equations to sloped surfaces is tested by comparing the calculated data with the monthly mean soil temperature data observed in Iowa and at 12 locations near the Tennessee - Kentucky border with various slope and aspect factors. Calculated soil temperature variations agreed well with the observed data. Finally, this method is applied to a simulation study of daily mean soil temperatures over sloped corn fields on a 30 m by 30 m resolution. The outputs reveal potential effects of topography including shading by neighboring terrain as well as the slope and aspect of the land itself on the soil temperature.

• Journal of the Korean Geographical Society
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• v.49 no.5
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• pp.656-674
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• 2014

The objective of this study was to examine the distinctiveness and generality of landforms of the Korean peninsula, and further discover geomorphological principle that can be applied to land and environmental management in Korea. The research targeted East Asia and Korea, with terrain analysis conducted at a continental scale, national scale, and regional scale sequentially. East Asia displays complicated characteristics and evolutionary history of geotectonics, but exhibits distinct northeast-southwest geomorphological structure and connectivity at the continental level. While the Korean peninsula follows this pattern on a continental scale, it also features NNW-SSE direction (Nangrim and Taebaek Mountains) geomorphological connectivity that intersects at a right angle. From a national perspective, the Korean peninsula hosts the most diverse geomorphological features within East Asia. It does not have a high average altitude, but has relatively high slope angle and intricate topographical distribution in comparison to neighboring areas. While the mountains and plains of the Korean peninsula display a smooth connection, geomorphologically similar areas such as Shikhote-Alin, Huanan in China, and Japan have clear characteristics that divide the mountains and plains. Despite the distinctiveness and diversity that appear in East Asian topography on the regional scale, the connectivity that links the top of mountain (hill) to stream is identical among all areas as a general rule. It is collectively considering the connectivity and the geomorphological and ecological processes that arise within this connectivity that will serve as the focal point for sustainable landscape management.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.3
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• pp.13-26
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• 2015

Many urban areas in Korea suffer from repeated flood damage during intensive rainfall due to an increase in impervious areas caused by rapid urbanization and deteriorating sewage systems. A centralized stormwater management system has caused severe flood damage in an area that has proven unable to accommodate recent climate change and a rise in precipitation. Most flooding prevention projects that have been recently implemented focus on increasing drainage system capacity by expanding the size of sewer pipes and adding pumping stations in downstream areas. However, such measures fail to provide sustainable solutions since they cannot solve fundamental problems to reduce surface runoff caused by urbanization across the watershed. A decentralized stormwater management system is needed that can minimize surface runoff and maximize localized retention capacity, while maintaining the existing drainage systems. This study proposes a stormwater management corridor for the flood-prone watershed in the city of Dongducheon. The corridor would connect the upstream, midstream, and downstream zones using various methods for reducing stormwater runoff. The research analyzed surface runoff patterns generated across the watershed using the Modified Rational Method considering the natural topography, land cover, and soil characteristics of each sub-watershed, as well as the urban fabric and land use. The expected effects of the design were verified by the retainable volume of stormwater runoff as based on the design application. The results suggest that an open space network serve as an urban green infrastructure, potentially expanding the functional and scenic values of the landscape. This method is more sustainable and effective than an engineering-based one, and can be applied to sustainable planning and management in flood-prone urban areas.