• Title/Summary/Keyword: 수치지표면모델

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Distribution of Surface Solar Radiation by Radiative Model in South Korea (복사 모델에 의한 남한의 지표면 태양광 분포)

  • Zo, Il-Sung;Jee, Joon-Bum;Lee, Won-Hak;Lee, Kyu-Tae;Choi, Young-Jean
    • Journal of Climate Change Research
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    • v.1 no.2
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    • pp.147-161
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    • 2010
  • The temporal and spatial distributions of surface solar radiation were calculated by the one layer solar radiative transfer model(GWNU) which was corrected by multi layer Line-by-Line(LBL) model during 2009 in South Korea. The aerosol optical thickness, ozone amount, cloud fraction and total precipitable water were used as the input data for GWNU model run and they were retrieved from Moderate Resolution Imaging Spectrometer(MODIS), Ozone Monitoring Instrument(OMI), MTSAT-1R satellite data and the Regional Data Assimilation Prediction System(RDAPS) model result, respectively. The surface solar radiation was calculated with 4 km spatial resolution in South Korea region using the GWNU model and the results were compared with surface measurement(by pyranometer) data of 22 KMA solar sites. The maximum values(more than $5,400MJ/m^2$) of model calculated annual solar radiation were found in Andong, Daegu and Jinju regions and these results were corresponded with the MTSAT-1R cloud amount data. However, the spatial distribution of surface measurement data was comparatively different from the model calculation because of the insufficient correction and management problems for the sites instruments(pyranometer).

Distribution of Photovoltaic Energy Including Topography Effect (지형 효과를 고려한 지표면 태양광 분포)

  • Jee, Joon-Bum;Zo, Il-Sung;Lee, Kyu-Tae;Choi, Young-Jean
    • Journal of the Korean earth science society
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    • v.32 no.2
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    • pp.190-199
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    • 2011
  • A photovoltaic energy map that included a topography effect on the Korean peninsula was developed using the Gangneung-Wonju National University (GWNU) solar radiation model. The satellites data (MODIS, OMI and MTSAT-1R) and output data from the Regional Data Assimilation Prediction System (RDAPS) model by the Korea Meteorological Administration (KMA) were used as input data for the GWNU model. Photovoltaic energy distributions were calculated by applying high resolution Digital Elevation Model (DEM) to the topography effect. The distributions of monthly accumulated solar energy indicated that differences caused by the topography effect are more important in winter than in summer because of the dependency on the solar altitude angle. The topography effect on photovoltaic energy is two times larger with 1 km resolution than with 4 km resolution. Therefore, an accurate calculation of the solar energy on the surface requires high-resolution topological data as well as high quality input data.

A Geomorphological Classification System to Chatacterize Ecological Processes over the Landscape (생태환경 특성 파악을 위한 지형분류기법의 개발)

  • Park Soo-Jin
    • Journal of the Korean Geographical Society
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    • v.39 no.4
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    • pp.495-513
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    • 2004
  • The shape of land surface work as a cradle for various environmental processes and human activities. As spatially distributed process modelings become increasing important in current research communities, a classification system that delineates land surface into characteristic geomorphological units is a pre-requisite for sustainable land use planning and management. Existing classification systems are either morphometric or generic, which have limitations to characterize continuous ecological processes over the landscape. A new classification system was developed to delineate the land surface into different geomorphological units from Digital Elevation Models(DEMs). This model assumes that there are pedo-geomorphological units in which distinct sets of hydrological, pedological, and consequent ecological processes occur. The classification system first divides the whole landsurface into eight soil-landscape units. Possible energy and material nows over the land surface were interpreted using a continuity equation of mass flow along the hillslope, and subsequently implemented in terrain analysis procedures. The developed models were tested at a 12$\textrm{km}^2$ area in Yangpyeong-gun, Kyeongi-do, Korea. The method proposed effectively delineates land surface into distinct pedo-geomorphological units, which identify the geomorphological characteristics over a large area at a low cost. The delineated landscape units mal provide a basic information for natural resource survey and environmental modeling practices.

NDVI 시계열 시리즈에 의한 한반도 지표면 변화 추적

  • Lee, Sang-Hun
    • Proceedings of the KSRS Conference
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    • 2009.03a
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    • pp.97-100
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    • 2009
  • The surface parameters associated with the land are usually dependent on the climate, and many physical processes that are displayed in the image sensed from the land then exhibit temporal variation with seasonal periodicity. An adaptive feedback system proposed in this study reconstructs a sequence of images remotely sensed from the land surface having the physical processes with seasonal periodicity. The harmonic model is used to track seasonal variation through time, and a Gibbs random field (GRF) is used to represent the spatial dependency of digital image processes. In this study, the Normalized Difference Vegetation Index (NDVI) was computed for one week composites of the Advanced Very High Resolution Radiometer (AVHRR) imagery over the Korean peninsula for 1996 and 2000 using a dynamic technique, and the adaptive reconstruction of harmonic model was then applied to the NDVI time series for tracking changes on the ground surface. The results show that the adaptive approach is potentially very effective for continuously monitoring changes on near-real time.

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A Study of Three Dimensional DSM Development using Self-Developed Drone (드론을 활용한 3차원 DSM추출을 위한 연구)

  • Lee, Byung-Gul
    • Journal of the Korean earth science society
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    • v.39 no.1
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    • pp.46-52
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    • 2018
  • This paper is to study the development of three dimensional Digital Surface Model (DSM) using photogrammetry technique based on self-developed Drone (Unmanned Aerial Vehicle (UAV)). To develop DSM, we selected a study area in Jeju island and took 24 pictures from the drone. The three dimensional coordinates of the photos were made by Differential Global Positioning System (DGPS) surveying with 10 ground control points (GCP). From the calculated three dimensional coordinates, we produced orthographic image and DSM. The accuracy of DSM was calculated using three GCPs. The average accuracy of X and Y was from 8.8 to 14.7 cm, and the accuracy of Z was 0.8 to 12.4 cm. The accuracy was less than the reference accuracy of 1/1,000 digital map provided by National Geographic Information Institute (NGII). From the results, we found that the self-developed drone and the photogrammetry technique are a useful tool to make DSM and digital map of Jeju.

Numerical Analysis of Wind Driven Current and Mesoscale Air Flow in Coastal Region with Land Topography (육상지형을 고려한 연안해역에서의 취송류에 관한 수치해석)

  • Lee, Seong-Dae;Kim, In-Ho;Hong, Chang-Bae
    • Proceedings of the Korea Water Resources Association Conference
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    • 2006.05a
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    • pp.1925-1930
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    • 2006
  • A quasi depth-varying mathematical model for wind-generated circulation in coastal areas, expressed in terms of the depth-averaged horizontal velocity components and free surface elevation was validated and used to understand the diurnal circulation process. The wind velocity is considered as a dominant factor for driving the wind generated current. In this paper, three dimensional numerical experiments that included the land topography were used to investigate the mesoscale air flow over the coastal regions. The surface temperature of the inland was determined through the surface heat budget consideration with inclusion of a layer of vegetation. A series of numerical experiments were then carried out to investigate the diurnal response of the air flow and wind-generated circulation to various types of surface inhomogeneities.

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A Comparison of Blast Load in a Simplified Analytical Model of Rigid Column (강체 기둥의 단순 해석 모델에서의 폭발 하중 비교)

  • Park, Hoon
    • Explosives and Blasting
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    • v.37 no.3
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    • pp.1-12
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    • 2019
  • The analysis methods of blast analysis models are classified into direct analysis and indirect analysis, and the latter is divided into semi-empirical and numerical analysis methods. In order to evaluate the applicability of the ELS blast analysis program, which is a program for analyzing the semi-empirical models, this study selected a simplified analytical model and examined the blast load characteristics of free-air burst explosion and surface burst explosion by using AT-Blast, RC-Blast, and Kinney and Graham's empirical equations, which are the semi-empirical analysis programs. As a result of analyzing the explosion pressure for the scaled distance and the incidence angle for the simplified analytical model, an appropriate analysis can be performed when the range of the scaled distance in the free-air burst explosion analysis was 0.3~0.461 and when the range of the scaled distance in the surface burst explosion analysis was 0.378~0.581. In terms of the incidence angle, the results analyzed within $45^{\circ}$ were considered to be appropriate.

Calibration and Validation of SWAT for the Neponset River Watershed in Boston (보스턴 넷폰셋강의 수질체계에 대한 스왓모델의 교정과 유효성 검증)

  • Lee, Ja-Won
    • Journal of the Korean association of regional geographers
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    • v.14 no.1
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    • pp.19-26
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    • 2008
  • A validation study has been performed using the Soil and Water Assessment Tool(SWAT) model with data collected for the Neponset River watershed, which includes roughly 130 square miles of land located southwest of Boston. All of this land drains into the Neponset River, and ultimately into Boston Harbor. This paper presents the methodology of a SWAT model. The calculated contribution of the baseflow to the streamflow is far too high whereas the interflow is strongly underestimated. Alternatively, the modified and calibrated model yields far better results for the catchment. The modification allows hydrological processes to be modeled while not restraining the applicability of the model to catchments with other characteristics. For this study, the SWAT 2005 model is used with ArcGIS 9.1 as an interlace, and sensitivity analysis is performed to provide rough estimated values before adjusting sensitive input parameters during calibration period.

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Accuracy Evaluation of Floodplain Topography Survey Using Small-scale UAV (소형 UAV를 이용한 홍수터 지형측량 정확도 평가)

  • Kwak, Sunghyun;Seo, Yong Jae;Song, Jin Hun;Lyu, Siwan
    • Proceedings of the Korea Water Resources Association Conference
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    • 2016.05a
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    • pp.449-453
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    • 2016
  • 하천 구역에 존재하는 인력 및 장비의 접근이 물리적으로 불가능한 공간에 대한 지형정보 취득의 한계를 극복하기 위한 대안으로 소형 UAV(Unmanned Aerial Vehicle)의 활용성을 살펴보고자, 낙동강 달성보와 강정고령보 사이에 위치하는 습지구간에 대한 영상촬영 및 분석을 통한 지형측량을 실시하였다. 홍수터 지형측량에 있어 소형 UAV를 이용한 사진측량의 신뢰성과 정확성을 평가하기 위하여, Network RTK를 이용한 육상측량결과와 정사영상 분석결과를 비교하여 '항공레이저측량 작업규정'의 '수치표고모델 규격 및 정확도'에 제시된 기준에 의거하여 수직위치 정확도를 검토하였다. 검토 결과 과대오차를 배제할 경우 지표면 상태에 따라 1/1,000~1/5,000의 정사영상 및 수치표고모델 제작이 가능함을 확인할 수 있었다.

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Deformation Analysis of Shallow Tunnel Using Tunnel Model Test and Computational Analysis (모형시험과 수치해석을 이용한 저토피 터널의 변형거동에 관한 연구)

  • Lee, Jae-Ho;Kim, Young-Su;Moon, Hong-Duk
    • Journal of the Korean Geotechnical Society
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    • v.24 no.1
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    • pp.61-70
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    • 2008
  • The control and prediction of surface settlement, gradient and ground displacement are the main factors in shallow tunnel design and construction in urban area. For deformation analysis of shallow tunnel due to excavation it is important to identify possible deformation mechanism of shear bands developing from tunnel shoulder to the ground surface. This paper investigaties quantitatively the deformation behavior of shallow tunneling by model tunnel test and strain softening analysis Incorporating the reduction of shear stiffness and strength parameters. The comparison of model tunnel test result and numerical simulation using strain softening analysis showed good agreement in crown settlement, normalized subsidence settlement and developing shear bands above tunnel shoulder. In this study, it is blown that the strain softening modeling is applicable to the nonlinear deformation analysis of shallow tunnel.