• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.6
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• pp.571-581
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• 2020

Vegetation affects water level change and flow resistance in rivers and impacts waterway ecosystems as a whole. Therefore, it is important to have accurate information about the species, shape, and size of any river vegetation. However, it is not easy to collect full vegetation data on-site, so recent studies have attempted to obtain large amounts of vegetation data using terrestrial laser scanning (TLS). Also, due to the complex shape of vegetation, it is not easy to obtain accurate information about the canopy area, and there are limitations due to a complex range of variables. Therefore, the physical structure of vegetation was analyzed in this study by reconfiguring high-resolution point cloud data collected through 3-dimensional terrestrial laser scanning (3D TLS) in a voxel. Each physical structure was analyzed under three different conditions: a simple vegetation formation without leaves, a complete formation with leaves, and a patch-scale vegetation formation. In the raw data, the outlier and unnecessary data were filtered and removed by Statistical Outlier Removal (SOR), resulting in 17%, 26%, and 25% of data being removed, respectively. Also, vegetation volume by voxel size was reconfigured from post-processed point clouds and compared with vegetation volume; the analysis showed that the margin of error was 8%, 25%, and 63% for each condition, respectively. The larger the size of the target sample, the larger the error. The vegetation surface looked visually similar when resizing the voxel; however, the volume of the entire vegetation was susceptible to error.

• Proceedings of the Korea Water Resources Association Conference
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• 1991.07a
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• pp.102-113
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• 1991

한정된 수자원을 관리하기 위한 물관리시스템을 구축운영하는데 수문학적 물손실의 관점에서 증발산은 매우 중요한 요소이다. 본 연구에서는 이러한 증발산이 실제 유역에서 변화하는 것을 일별로 추정하기 위해서 유역일증발산 모형을 개발하여 실제증발산을 추정하였다. 실제증발산은 잠재증발산을 먼저 산정하고 이를 이용하여 강우차단에 의한 증발, 토양증발, 지표하 증산으로 나누어 추정하였다. 잠재증발산 추정방법은 토양-식생-대기의 관계를 정교히 모식할 수 있는 Penman-Monteith 방법을 채택하였고, 강우차단에 의한 증발은 Bultot와 Dupriez가 제안한 모형을, 토양증발은 Ritchie가 제시한 모형을 채택하였다. 증산은 토양층을 상부·하부층으로 나누어 상부층증산과 하부층 증산으로 분리 추정하였으며, 증발산과 토양수분의 관계는 Thornthwait-Mather의 관계를 이용하여 추정하였다. 이 모형의 타당성을 임업연구원에서 운영하고 있는 2개의 시험유역을 대상으로 검토하였다. 그결과 실제일증발산을 년단위로 계산한 실제증발산값은 물수지 개념에 의한 실제증발산결과와 비교할 때 약 8~30% 오차를 수반하고 있었다. 이러한 결과는 모형의 실제유역의 적용에 있어서 입력되는 여러 매개변수가 가정에 의해 결정된 것이기 때문일 것이라고 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.65-65
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• 2022

울창한 숲에도 어느 정도 햇빛은 들 듯이, 태양복사에너지는 식생의 잎과 흙에 모두 미치며, 그로 인해 증산과 증발이 각각 발생한다. 이러한 사실을 반영하는 것은 현존하는 증발산 산정 방법을 개선하여 더 나은 증발산 추정치를 구하는 데에 도움이 될 것이다. 이 연구에서는 증발 표면을 수직적으로 흙층(soil layer)과 잎층(canopy layer)으로 나눠진 다층 구조로 바라보고, 각 층에서 증발산을 계산하는 방법을 도입했다. 증발 표면을 수직 상에서 구분했기에 각 층의 환경 조건은 그 층을 대표하는 높이에서 관측된 기상자료를 활용할 수 있다. 또한, 식생 활기에 따른 각 층의 복사에너지 유입량과 기공의 여닫힘에 따른 Bowen 비를 통해 식생이 증발산에 미치는 영향을 반영하는 것이 가능하다. 본 연구에서는 Fluxnet에서 제공하는 공분산 방법(eddy covariance method)으로 측정한 자료를 참고하여 다층 구조가 실제 증발산 산정에 타당한가를 논했다. 시스템 내 변화는 주어진 조건에서 엔트로피가 최대로 생성되는 방향으로 발생한다는 Maximum Entropy Production (MEP) 이론을 기반으로 만들어진 증발산 산정법을 통해 각 층의 증발산을 계산했으며, 관측 증발산을 토대로 잎층과 흙층에 유입된 복사에너지의 크기를 비교했다. 결과적으로 잎층에 계산된 복사에너지 흡수능이 낙엽수림의 변화 주기를 잘 반영하는 것을 확인했으며 다층 구조를 도입하는 것이 증발산 산정 향상과 수문-식생 관계를 고려한 증발산 분석에 적절한 접근법임을 보였다.

• The Korean Journal of Ecology
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• v.27 no.3
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• pp.185-192
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• 2004

Vegetation established through the natural process, such as Quercus mongolica, Pinus densiflora, Q. variabilis, Q. acutissima, Carpinus laxiflora, Q. aliena and Q. serrata communities and artificially introduced vegetation, which are composed of Larix leptolepis and P. rigida plantations, are established in the mountainous land of the Mt. Songnisan National Park. On the other hand, the developed lands, which are consisted of agricultural folds, residential areas, commercial areas related to tourism, etc. appear in the lowland around streams. Based on the spatial distribution of vegetation, the southern district, which is attributed to Naesongni-myun by administrative system, showed higher natural degree and vegetation diversity. However, most of the other districts, which are attributed to Cheongcheon- and Chilseong-myuns, are covered with the Korean red pine forest, a product of artificial influence, and plantation also occupied higher percentage. Thereby both vegetation diversity and natural degree are lowering. A result of ordination by DCA showed that sands tended to be arranged by depending on the topographic condition. Species diversity of plant communities was higher in broad-leaved stands rather than in coniferous ones and in stands of the early stage than in ones of the late stage. The result of analysis on vegetation dynamics implied that vegetation of this region would be dominated by Carpinus laxiflora, Quercus mongolica and Pinus densiflora communities in the future. However, considered occurrence the of disturbance and response of vegetation on that, this estimation may different somewhat from an actual situation. Conservation strategies of the Mt. Songnisan National Park were discussed in viewpoints of landscape ecology, and conservation of major plant communities and biodiversity.

• Spatial Information Research
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• v.17 no.1
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• pp.117-129
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• 2009

South Korea has been undergoing spring drought periodically and diverse researches using vegetation index have been carried out to monitor spring droughts. The strength of the vegetation index-based drought monitoring is that the monitoring method enables efficient spatio-temporal grasp of changes in drought events. According to the development of low resolution satellite images such as MODIS, which are characterized by outstanding temporal resolution, the use of the method is expected to increase. Drought analysis using vegetation index considered only meteorological factor as a cause that affects vitality of vegetation. But many indirect and direct factors affect vegetation stress, So many uncertainties are involved in such method of analysis. To secure objectivity of drought analysis that uses vegetation index it is therefore necessary to compare the method with most representative drought analysis tools that are used for drought management. In this study, PDSI and SPI which a meteorological drought index that quantifies drought and that is used as a basic index for drought monitoring and MODIS NDVI are compared to propose correlation among them and to show usefulness of drought assessment that uses vegetation index. This study shows changing patterns of NDVI and SPI 6-month are similar and correlation between NDVI and SPI was highest in inland vegetation cover.

• Ecology and Resilient Infrastructure
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• v.7 no.2
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• pp.90-96
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• 2020

Recently, a method that applies laser scanning (LS) that acquires vegetation information such as the vegetation habitat area and the size of vegetation in a point cloud format has been proposed. When LS is used to investigate the physical shape of vegetation, it has the advantage of more accurate and rapid information acquisition. However, to examine uncertainties that may arise during measurement or post-processing, the process of adjusting the data by the actual data is necessary. Therefore, in this study, the physical structure of stems, branches, and leaves of woody vegetation in an artificially formed river channel was manually investigated. The obtained results then compared with the information acquired using the three-dimensional terrestrial laser scanning (3D TLS) method, which repeatedly scanned the target vegetation in various directions to obtain relevant information with improved precision. The analysis demonstrated a negligible difference between the measurements for the diameters of vegetation and the length of stems; however, in the case of branch length measurement, a relatively more significant difference was observed. It is because the implementation of point cloud information limits the precise differentiation between branches and leaves in the canopy area.

• Korean Journal of Environmental Biology
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• v.40 no.1
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• pp.99-111
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• 2022

Vegetation is the basis for biodiversity conservation and sustainable development. In the Environmental Impact Assessment (EIA), which is the most direct and efficient policy measure to prevent degradation of nature, vegetation-related assessment has limitations as it is not based on quantitative and scientific methods. In addition, it focuses on the presence of protected species; hence, it does not take into account the role of vegetation as a habitat on a wide-area scale. As a way to overcome these limitations, this study aims to contribute to the quantification and advancement of future EIA on vegetation. Through the review of previous studies, core areas, connectivity, and vegetation condition were derived as the items to be dealt within the macroscopic aspect of vegetation impact assessment. Each item was spatially constructed using land cover maps and satellite imageries, and time series change analysis was performed. As a result, it was found that vegetation has been continuously deteriorating due to development in all aspects, and in particular, development adversely affects not only the inside of the project site but also the surrounding area. Although this study suggested the direction for improvement of the EIA in the vegetation sector based on data analysis, a more specific methodology needs to be established in order to apply it to the actual EIA process. By actively utilizing various environmental spatial data, the impact of the development on the natural ecosystem can be minimized.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.14 no.1
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• pp.81-88
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• 1996

Remote sensing technique is a probable means to estimate distribution of actual evapotranspiration over wide area in connection with regional characteristics of vegetation and landuse. Factors controlling evapotranspiration from ground are air temperature, humidity, wind, radiation, soil moisture and so on. Not only the vegetation influences directly the evapotranspiration, but also these factors strongly influnce the vegetation at the area. Therefore we can expect high correlation between the evapotranspiration and the vegetation. To grasp the state of vegetation at any point, NDVI calculated from NOAA/AVHRR data is utilized. It can be considered that evapotranspiration at a forest region is linearly proportional to the NDVI. Here, a model which adopts a direct method to estimate actual evapotranspiration is developed by using the relationship between NDVI and evapotranspiration. This method makes possible to estimate evapotranspiration of Korean Peninsula including North Korea where enough meteorological and hydrological data are unavailable.

• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.3
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• pp.79-89
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• 2004

Remote sensing technique is a probable means to estimate distribution of actual evapotranspiration in connection with regional characteristics of vegetation and landuse. The factors controlling evapotranspiration from ground surface are air temperature, humidity, wind, radiation, soil moisture and so on. Not only the vegetation influences directly the evapotranspiration, but also these factors strongly influences the vegetation growth at the area. Therefore, it can be expected that evapotranspiration is highly correlated to vegetation condition. The normalized difference vegetation index (NDVI) showed excellent ability to get the vegetation information. The NDVI is obtained using NOAA/AVHRR have been studied as a tool for vegetation monitoring. In this paper, a simple method to estimate actual avapotranspiration is proposed based on vegetation and meteorological data.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.550-550
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• 2015

습지는 다양한 생물종의 서식지를 제공하고 있다. 습지는 물과 영양분이 충분하기 때문에 식물이 서식하기 좋을 것 같지만 실제적으로 습지에서는 잦은 수위변동이 발생하므로 습지에서 식물은 생리적으로 가혹한 환경에 처해 있다고 할 수 있다. 따라서 습지 식물은 서식하는데 있어 수위의 영향을 많이 받는다고 할 수 있으며 습지 조성 및 관리에 있어 습지 식물의 서식환경을 분석하는 것이 필요하다. 이에 본 연구에서는 습지 식물종의 특징과 최적의 생육환경과의 관계를 규명하기 위해 식생서식환경을 침수심과 연계하여 분석하였다. 이를 위해 식물 군락이 잘 발달되어 있는 남한강의 비내섬 습지에 대해 유황분석을 수행하였고, 유황에 따른 유량을 모의하였다. 모의된 유량과 HEC-RAS 모형을 이용하여 유황별 홍수위를 산정하였다. 또한 RAS Mapper를 이용하여 침수심과 침수구역을 모의하고, 이를 통해 여러 생물군 중 침수심에 영향을 많이 받는 식물의 서식환경을 분석하였다. 분석 결과, 버드나무군락은 침수가 발생하지 않는 지역 및 0~0.8m의 침수심, 물억새군락은 침수가 발생하지 않는 지역 및 0~0.4m의 침수심, 쑥-망초군락과 달뿌리풀군락은 0~0.4m의 침수심, 그리고 환삼덩굴군락은 0~0.8m의 침수심이 발생하는 지역에서 서식하는 것으로 분석되었다. 본 연구는 유황에 따른 침수심에 대한 식생서식환경을 분석한 것으로 식생을 고려한 인공습지 조성이나 하천설계에 있어 기초적인 자료가 될 것으로 기대되며 보다 더 정확한 연구를 위해서는 장기모니터링을 통한 식생 자료의 축적 및 더 효과적인 수위-식생 연계분석 방법론에 대한 연구가 필요할 것으로 판단된다.