• Journal of Ecology and Environment
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• v.29 no.3
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• pp.227-235
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• 2006

Changes of the species diversity and development of vegetation structure during abandoned field succession after shifting cultivation were investigated in Pyoungchang, Gangwon-Do, Korea. The height of top layer tended to increase rapidly during the earlier successional stages and stabilize in the later successional stage. The heights of top layer in the 10, 20, 50 and 80 year old-field were 4, 9, 18 and 18 m, respectively. In this region, thirty five year after abandonment need for the development to the normal forest formed by 4 stratum structure, tree, sub-tree, shrub and herb layer. Among the vegetation values, Ivc showed a tendency to increase logarithmically, and Hcl a tendency to increase linearly during abandoned field succession. Species diversity showed the peak in mid-successional stages ($10{\sim}20$ year old-field) and declined slightly thereafter. Species diversity was correlated closely with the species richness than the evenness. The most woody species established in the earlier stage ($2{\sim}6$ year old-field) and turned over their dominance step by step during succession. These results support the IFC model proposed by Egler (1954).

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2007.10a
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• pp.450-452
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• 2007

• Journal of Korea Water Resources Association
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• v.48 no.11
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• pp.891-903
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• 2015

This paper presents numerical simulations of flow around a circular patch of vegetation using a depth-averaged two-dimensional numerical model which is capable of simulating flow structure in vegetated open channel. In order to account for vegetation effect, drag force terms are included in governing equations. Numerical simulations are conducted with various solid volume fractions (SVF). Flow passes through a circular patch and low velocity region, which is called wake region, is formed downstream of the patch. When SVF is larger than 0.08, a recirculation is observed. The location of the recirculation is moved further downstream as SVF decreases. Von-$K{\acute{a}}rm{\acute{a}}n$ vortex street is developed beyond the wake region due to interaction between two shear layers induced by a circular patch of vegetation. The vortex is developed as SVF is larger than 0.08, and the location of the vortex is consistent with the maximum of turbulence kinetic energy. The location of the peak of turbulence kinetic energy is moved further downstream as SVF decreases.

• Journal of Environmental Impact Assessment
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• v.24 no.5
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• pp.516-531
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• 2015

In this study, a software module to predict the effectiveness of vegetation buffer strip (VBS) has been developed for using with Chemicals, Agricultural Management and Erosion Losses (CAMEL), a distributed watershed model. Most basic functions for the VBS module are same as CAMEL except functions newly developed to implement sedimentation enhancement by vegetation and level spreaders. For verification of the VBS module, sensitivity analyses for length, roughness, soil and vegetation type of VBS were carried out using a test grid cell. The surface discharge of sediment are highly sensitive to the roughness coefficient of VBS. The removal efficiencies of VBS for the surface discharges of sediment and TP are generally high regardless of environment changes. The surface discharges of TOC and TN are highly sensitive to the length and soil of VBS. The removal efficiencies of VBS for the surface discharges of TOC and TN are generally lower than those of sediment and TP. The newly developed VBS module reasonably simulates the removal efficiencies of surface discharges that vary according to the environment changes. It is expected that this VBS module can be used for evaluating the effectiveness of VBS-based best management practices to be applied to reduce pollution discharges from various non-point sources.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.108-108
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• 2011

기후 변화로 인한 수문 환경의 변화에 따라 수문 모형을 이용한 정확한 예측이 필요하다. 수문 현상의 예측을 위하여 사용되고 있는 수문 모형인 Common Land Model(CLM)은 Soil-Vegetation-Atmosphere Transfer(SVAT) 모형 중 하나로 비교적 적은 변수를 이용하여 현실적인 결과를 도출하므로 세계적으로 널리 이용되고 있다. 이에 반해 국내에서는 모형의 구동을 위한 입력 자료의 미흡으로 인해 실질적인 연구 사례가 부족한 실정이다. 본 연구에서는 해남의 KoFlux 지점을 대상으로 Korea Flux Network(KoFlux) 자료와 Korea Land Data Assimilation System(KLDAS) 자료를 CLM에 강제시켜 국내의 모형의 적용성에 대하여 검증하였다. KoFlux는 에디 공분산 시스템을 기반으로 지표면과 대기 사이의 Flux에 대한 측정 시스템을 운영하며 SVAT 모형의 구동을 위한 수문학적 인자들을 제공하고 있으며, KLDAS는 한반도지표동화자료체계로 위성 및 현장기반 관측 자료들을 지면모형에 적용시켜 자료동화방법을 통하여 지표 변수들을 제공하고 있다. 모형의 산출 결과는 해남 지점의 관측 자료와 비교를 통하여 CLM 모형의 적용 가능성을 검증하였고 두 결과 모두 관측 데이터와의 경향성이 일치하는 것으로 나타났다. 결과 모두 신뢰할 만한 값으로 추정되며, 이를 통하여 국내의 CLM 모형 적용 가능성을 확인하였고, 국내에서의 지점 자료가 부족한 부분에 대한 KLDAS 자료의 이용 가능성 또한 확인하였다.

• Korean Journal of Hydrosciences
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• v.8
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• pp.97-110
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• 1997

Quantifying water balance components is crucial to understanding the basic hydrology and hydrochemistry. An importance of water balace studies has been emphasized from the need to grasp the actual condition of water resources and environmental changes including climatic changes. This paper proposes a method for evaluating water balance components based on the vegetation monitor using remote sensing data. Here, the evapotranspiration model adopts a direct method by using NDVI(Normalized Difference Vegetation Index) calculated from NOAA/AVHRR data and a detailed descriptionof water balance by using the evapotranspiration over the Korean Peninsula. In the study, areal distribution data sets of water balance components are produced using NDVI and a simplified water balance model. This method enables one to discuss the hydrological problems for North Korea where insufficient meteorological and hydrological data exist. The results obtained indicate the specific regional features on water inventory and fluctuation in water balance.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.195-197
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• 2003

Soil moisture is a crucial variable in research works of hydrology, meteorology and plant sciences. Adequate soil moisture is essential for plant growth; excesses and deficits of soil moisture must be considered in agricultural practices. There are already several remote sensing methods used for monitoring soil moisture, such as thermal inertia, vegetation water-supplying index, crop water stress index and multi-factor regression. In this paper, an improved method has been discussed which is based on the thermal inertia. We analyzed the problems of monitoring soil moisture using satellites at first, and then put forward an simplified method which directly uses land surface temperature differences to measure soil moisture. Also we have taken the influence of vegetation into account, and import NDVI into the model. The method was used in the study of soil moisture in Heilongjiang Province, China, and we draw the conclusion by the experiments that the model can evidently increase the precision of monitoring soil moisture.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.3 no.2
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• pp.40-45
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• 1992

A simple emission model applicable for low scattering (scattering << absorption) anisotropic layer is developed and applied to the interpretation of measurements of microwave emission from row crops. The vegetation layer of row crops is modeled as a random slab embedded with small spheroid with major axis aligend paralel to the crop-row direction. The total emission is given in a simple algebraic form based on the zero-order radiative transfer theory. The single scattering albedo for spheroid and its polarimetric phase function are presented. The effects of layer azimuthal dependence on emission are accounted for by using an anisotropic albedo in the zero-order transfer theory. The developed emission theory favorably compares with the brightness temperature measured over soybeans canopy.

• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.1
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• pp.25-34
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• 2020

Land use in watersheds has been shown to be a major driving factor in determining the status of the water quality of streams. In this light, scientists have been investigating the roles of riparian vegetation on the relationships between land use in watersheds and the associated stream water quality. Numerous studies reported that riparian vegetation could alleviate the adverse effects caused by land use in watersheds and on stream water quality through various hydrological, biochemical and ecological mechanisms. However, this concept has been criticized as the true effects of riparian vegetation must be assessed by comprehensive models that mimic real environmental settings. This study aimed to estimate a comprehensive structural equation model integrating topography, land use, and characteristics of riparian vegetation. We used water quality data from the Nakdong River system monitored under the National Aquatic Ecosystem Monitoring Program (NAEMP) of the Korean Ministry of Environment (MOE). Also, riparian vegetation data and land use data were extracted from the Land Use/Land Cover map (LULC) produced by the MOE. The number of structural equation models (SEMs) were estimated in Amos of IBM SPSS. Study results revealed that land use was determined by elevation, and developed areas within a watershed significantly increased the concentration of Total Nitrogen (TN) in streams and LDI in riparian vegetation. On the contrary, developed areas significantly reduced LPI and PLAND. At the same time, PLAND and LDI significantly reduced the concentration of TN in streams. Thus, it was clear that developed areas in watersheds had both a direct and an indirect impact on the concentration of TN in streams, and spatial pattern and the amount of vegetation of riparian vegetation could significantly alleviate the negative impacts of developed areas on TN concentration in streams. To enhance stream water quality, reducing developed areas in a watershed is critical for long-term watershed management plans, restoration patterns for riparian vegetation could be immediately implemented since riparian areas were less developed than most other watersheds.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.4
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• pp.158-174
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• 2018

The leaf area index (LAI) is a major factor explaining the photosynthesis of vegetation, evapotranspiration, and energy exchange between the earth surface and atmosphere, and there have been studies on accurate and applicable LAI estimation methods. This study aimed to investigate the relationship between the actual LAI data, UAV image-based vegetation index, canopy height and satellite image (Sentinel-2) LAI and to present an effective LAI estimation method using UAV. As a result, among the six vegetation indices in this study, NDRE ($R^2=0.496$) and CIRE ($R^2=0.443$), which contained red-edge band, showed a high correlation. The application of the canopy height model data to the vegetation index improved the explanatory power of the LAI. In addition, in the case of NDVI, the saturation problem caused by the linear relationship with LAI was addressed. In this study, it was possible to estimate high resolution LAI using UAV images. It is expected that the applicability of such data will be improved if calibration and correction steps are carried out for various vegetation and seasonal images.