• Title/Summary/Keyword: Landsat Satellite Images

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Determination of Fire Severity and Deduction of Influence Factors Through Landsat-8 Satellite Image Analysis - A Case Study of Gangneung and Donghae Forest Fires - (Landsat-8 위성영상 분석을 통한 산불피해 심각도 판정 및 영향 인자 도출 - 강릉, 동해 산불을 사례로 -)

  • Soo-Dong Lee;Gyoung-Sik Park;Chung-Hyeon Oh;Bong-Gyo Cho;Byeong-Hyeok Yu
    • Korean Journal of Environment and Ecology
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    • v.38 no.3
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    • pp.277-292
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    • 2024
  • In order to manage large-scale forest fires concentrated in Gangwon-do and Gyeongsangbuk-do with severe topographical heterogeneity, a decision-making process through efficient and rapid damage assessment using satellite images is essential. Accordingly, this study targets a large-scale forest fire that ignited in Gangneung and the Donghae, Gangwon-do on March 5, 2022, and was extinguished around 19:00 on March 8, to estimate the fire severity using dNBR and derive environmental factors that affect the grade. As environmental factors, we quantified the regular vegetation index representing vegetation or fuel type, the forest index that classifies tree species, the regular moisture index representing moisture content, and DEM in relation to topography, and then analyzed the correlation with the fire severity. In terms of fire severity, the widest range was 'Unbured' at 52.4%, followed by low severity at 42.9%, medium-low severity at 4.3%, and medium-high severity at 0.4%. Environmental factors showed a negative correlation with dNDVI and dNDWI, and a positive correlation with slope. Regarding vegetation, the differences between coniferous, broad-leaved, and other groups in dNDVI, dNIWI, and slope, which were analyzed to affect the fire severity, were analyzed to be significant with p-value < 2.2e-16. In particular, the difference between coniferous and broad-leaved forests was clear, and it was confirmed that coniferous forest suffered more damage than broad-leaved forest due to the higher fire severity in the Gangwon-do region, including Pinus densiflora, which are dominant species, as well as P. koraiensis, P. rigida and P. thunbergii.

Geographical Study on the Location of Nokdun-do in Lower Tuman River (두만강 하구 녹둔도의 위치 비정에 관한 연구)

  • 이옥희
    • Journal of the Korean Geographical Society
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    • v.39 no.3
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    • pp.344-359
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    • 2004
  • This geographical study is to identify the reality of Nokdun island which was once settled and farmed by our ancestor, but currently the island is do facto under Russia's control. Various historical documents including old maps, current large scale maps and satellite images besides field work were used for full analysis. According to historical records, up until Chosun Dynasty, Nokdun island in the lower Tuman river was one of the frontier fortified base crossed the river for the northern defense as well as seasonal farming for the farmer of Kyounghung border area. Even though the island was unjustly lost to Russia by the Beijing Treaty in the late Chosun period, the whole area of Nokdun was occupied and farmed by sole Koreans until the deportation by Stalin was forcibly measured. In these days due to the change of Tumn river channel and new deposition by river it became very difficult to find the original shape of Nokdun island. However, through intensive field works based on historical records, the research team found out the existence of the old wet-dry fields, old rural farmhouse remnants, and small and medium size of millstones that are supporting the reality of the island. Especially, the team traced a mud fortress presumedly built in the early Chosun period. We believe it might allow to allocate the exact location of Nokdun island in near future.

A Study on the Movement of Street-based Urban Morphology Using Analysis of Integrated Land Use-Transportation (토지이용-교통 통합적 분석을 통한 도로 기반 도시 형태학적 변화에 관한 연구)

  • Joo, Yong-Jin
    • Spatial Information Research
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    • v.19 no.3
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    • pp.63-72
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    • 2011
  • Urban space structure tends to have a significant change in accordance with maintenance of urban infrastructure such as a traffic route. For this reason, quantitative analysis has been needed to establish spatial distribution and location patterns by considering change of both road accessibility and urban infrastructure level, which can have the most pervasive influence in urban development process. Therefore, this paper aims to analyze spatio-temporal urban morphology through considering distribution patterns of road among transportation infrastructures, population, and spatial structure of metropolitan areas, focusing on Seoul where population growth and the size of urban area have been dramatically increased. For this, we firstly developed and constructed time-series GIS database by using satellite images and topographic maps of the last 70 years to analyze variables which affect urban growth and transportation. In particular, we analyzed the transform of the system of the street by Space Syntax which is able to grasp hierarchical spatial structure through visibility of space and spatial cognition in terms of accessibility. What's more, we analyzed and visualized the relationship urban morphology and road according the regions of Seoul through IPA(Importance Performance Analysis). In terms of the integration land-use and transportation, Space Syntax approach is expected to contribute to efficient urban planning through understanding the influence which various transportation phenomena has an effect on urban development patterns.

Assessment of Future Climate and Land Use Change on Hydrology and Stream Water Quality of Anseongcheon Watershed Using SWAT Model (II) (SWAT 모형을 이용한 미래 기후변화 및 토지이용 변화에 따른 안성천 유역 수문 - 수질 변화 분석 (II))

  • Lee, Yong Jun;An, So Ra;Kang, Boosik;Kim, Seong Joon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.6B
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    • pp.665-673
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    • 2008
  • This study is to assess the future potential climate and land use change impact on streamflow and stream water quality of the study watershed using the established model parameters (I). The CCCma (Canadian Centre for Climate Modelling and Analysis) CGCM2 (Canadian Global Coupled Model) based on IPCC SRES (Special Report Emission Scenarios) A2 and B2 scenarios were adopted for future climate condition, and the data were downscaled by Stochastic Spatio-Temporal Random Cascade Model technique. The future land use condition was predicted by using modified CA-Markov (Cellular Automata-Markov chain) technique with the past time series of Landsat satellite images. The model was applied for the future extreme precipitation cases of around 2030, 2060 and 2090. The predicted results showed that the runoff ratio increased 8% based on the 2005 precipitation (1160.1 mm) and runoff ratio (65%). Accordingly the Sediment, T-N and T-P also increased 120%, 16% and 10% respectively for the case of 50% precipitation increase. This research has the meaning in providing the methodological procedures for the evaluation of future potential climate and land use changes on watershed hydrology and stream water quality. This model result are expected to plan in advance for healthy and sustainable watershed management and countermeasures of climate change.

Analysis of Hydrological Impact Using Climate Change Scenarios and the CA-Markov Technique on Soyanggang-dam Watershed (CA-Markov 기법을 이용한 기후변화에 따른 소양강댐 유역의 수문분석)

  • Lim, Hyuk-Jin;Kwon, Hyung-Joong;Bae, Deg-Hyo;Kim, Seong-Joon
    • Journal of Korea Water Resources Association
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    • v.39 no.5 s.166
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    • pp.453-466
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    • 2006
  • The objective of this study was to analyze the changes in the hydrological environment in Soyanggang-dam watershed due to climate change results (in yews 2050 and 2100) which were simulated using CCCma CGCM2 based on SRES A2 and B2. The SRES A2 and B2 were used to estimate NDVI values for selected land use using the relation of NDVI-Temperature using linear regression of observed data (in years 1998$\sim$2002). Land use change based on SRES A2 and B2 was estimated every 5- and 10-year period using the CA-Markov technique based on the 1985, 1990, 1995 and 2000 land cover map classified by Landsat TM satellite images. As a result, the trend in land use change in each land class was reflected. When land use changes in years 2050 and 2100 were simulated using the CA-Markov method, the forest class area declined while the urban, bareground and grassland classes increased. When simulation was done further for future scenarios, the transition change converged and no increasing trend was reflected. The impact assessment of evapotranspiration was conducted by comparing the observed data with the computed results based on three cases supposition scenarios of meteorological data (temperature, global radiation and wind speed) using the FAO Penman-Monteith method. The results showed that the runoff was reduced by about 50% compared with the present hydrologic condition when each SRES and periods were compared. If there was no land use change, the runoff would decline further to about 3$\sim$5%.