• 상하수도학회지
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• 제35권2호
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• pp.163-174
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• 2021

Heatwaves are one of the most common phenomena originating from changes in the urban thermal environment. They are caused mainly by the evapotranspiration decrease of surface impermeable areas from increases in temperature and reflected heat, leading to a dry urban environment that can deteriorate aspects of everyday life. This study aimed to calculate daily maximum ground surface temperature affecting heatwaves, to quantify the effects of urban thermal environment control through water cycle restoration while validating its feasibility. The maximum surface temperature regression equation according to the impermeable area ratios of urban land cover types was derived. The estimated values from daily maximum ground surface temperature regression equation were compared with actual measured values to validate the calculation method's feasibility. The land cover classification and derivation of specific parameters were conducted by classifying land cover into buildings, roads, rivers, and lands. Detailed parameters were classified by the river area ratio, land impermeable area ratio, and green area ratio of each land-cover type, with the exception of the rivers, to derive the maximum surface temperature regression equation of each land cover type. The regression equation feasibility assessment showed that the estimated maximum surface temperature values were within the level of significance. The maximum surface temperature decreased by 0.0450℃ when the green area ratio increased by 1% and increased by 0.0321℃ when the impermeable area ratio increased by 1%. It was determined that the surface reduction effect through increases in the green area ratio was 29% higher than the increasing effect of surface temperature due to the impermeable land ratio.

• 대한원격탐사학회지
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• 제28권2호
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• pp.203-214
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• 2012

콘크리트와 아스팔트가 상당 부분을 차지하는 도시의 물리적인 환경은 도시열섬효과를 일으키는 주요 원인이며, 일차적으로 토지이용 또는 토양피복에 따른 지표면온도의 상승으로 나타난다. 본 연구에서는 도시의 토지피복유형이 지표면온도에 미치는 영향을 공간해상도가 다른 MODIS, Landsat ETM+과 RapidEye 위성영상을 사용하여 비교 분석해 보았다. 연구대상지인 일산 신도시지역의 지표면온도는 토지 이용에 따라 뚜렷이 구분되는 패턴을 보여주었는데 건폐율이 높은 저층단독주택지구보다 건폐율이 낮고 녹지율이 높은 고층 아파트단지의 지표면온도가 현저히 낮게 나타났다. 토지피복유형과의 관계는 건물이나 도로 등 도시화지역의 면적이 증가할수록 기후존의 지표면온도가 증가하고, 식생과 수면, 그림자 지역의 면적이 늘어날수록 지표면온도는 떨어진다. NDVI와 지표면온도 사이에도 음의 선형상관관계가 나타나지만, 계절적 영향을 배제하기 어렵다는 단점이 있다.

• 한국지구과학회지
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• 제23권1호
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• pp.1-14
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• 2002

The land-cover of two regions of South and North Korea included in one Landsat TM scene was investigated by comparing different seasons and different band data over the multiple land-cover types. The relationships between the intensities of two bands in the 2-D plot are mainly linear in band2 versus band1 and band3 versus band1, polygonal sporadic in band5 versus band1 and band7 versus band1, and almost tri-polarized in band4 versus band3. The 2-D plot of band4/band3 shows the best capability to discriminate different main land-cover such as water, vegetation and dry soil. Some discriminations are not clear between city and dry field, or mountain and plain field in the scene of September. The digital number data of band4 from vegetated zones show stronger reflectance in September rather than April, while other band values tend to be lager in April than in September over each land-cover. NDVI presents high value in both regions in September. However the image of Wonsan area in April suggests weak vigor of vegetation in comparison with Cholwon area. Band ratios are very effective in eliminating the influence of the complex topography. The proper pairing of the band ratio improved the discrimination capability of the land-cover; band5/band2 for dry soil, band4/band3 for vegetation and band1/band7 for the water. The RGB combination of the three band ratio pairs showed the best results in the discrimination of the land-cover of Wonsan, Cholwon and even the Demilitarized Zone.

• 한국측량학회지
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• 제36권3호
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• pp.135-152
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• 2018

The purpose of this study is to propose an optimal fusion method of aerial multi - sensor data to improve the accuracy of land cover classification. Recently, in the fields of environmental impact assessment and land monitoring, high-resolution image data has been acquired for many regions for quantitative land management using aerial multi-sensor, but most of them are used only for the purpose of the project. Hyperspectral sensor data, which is mainly used for land cover classification, has the advantage of high classification accuracy, but it is difficult to classify the accurate land cover state because only the visible and near infrared wavelengths are acquired and of low spatial resolution. Therefore, there is a need for research that can improve the accuracy of land cover classification by fusing hyperspectral sensor data with multispectral sensor and aerial laser sensor data. As a fusion method of aerial multisensor, we proposed a pixel ratio adjustment method, a band accumulation method, and a spectral graph adjustment method. Fusion parameters such as fusion rate, band accumulation, spectral graph expansion ratio were selected according to the fusion method, and the fusion data generation and degree of land cover classification accuracy were calculated by applying incremental changes to the fusion variables. Optimal fusion variables for hyperspectral data, multispectral data and aerial laser data were derived by considering the correlation between land cover classification accuracy and fusion variables.

• 한국물환경학회지
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• 제39권2호
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• pp.142-152
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• 2023

Infiltration is a process by which precipitation infuses into subsurface soils. The process determines the surface flow and baseflow volume, and it is one of most important hydrological processes regarding nonpoint source pollution management. Therefore, the Ministry of Environment has developed a guideline to determine the impervious area ratio to understand the hydrological process in administrative districts and watersheds. The impervious area ratio can be determined using land use or land cover maps. Three approaches were explored to determine the impervious area ratio in 25 districts in Seoul. The impervious area ratio was determined by employing the Land registration map and Land property data in the first approach, Land property map in the second approach, and Land cover map in the third approach. The ratio ranged from 38.96% to 83.01% in the first approach, 38.98% to 83.02% in the second approach, and 37.62% to 76.63% in the third approach. Although the ranges did not provide any significant differences in the approaches, some districts displayed differences up to 9.48% by the approach. These differences resulted from the fact that the data were land use or land cover, especially in the area of airport, residential complex area, and school sites. In other words, division of the pervious and impervious areas in an individual plot was not allowed in the Land registration map, while it was allowed in the Land cover map. Therefore, it was concluded that there is a need to revise the guideline so that a reasonable impervious area ratio can be determined in the districts.

• 환경영향평가
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• 제22권5호
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• pp.397-408
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• 2013

The purpose of this study is to analyze water cycle area ratio and spatial evaluation of water cycle in urban area of Changwon-si, Gyeongsangnam-do. Water cycle area ratio are analyzed by using spatial data of land-cover and land-use, and Hot spot analysis of GIS program was used for spatial evaluation of water cycle. The results are as below. Firstly, the high water cycle area ratio areas were forests, parks, and rivers, but urban areas covered asphalt and concrete were low under 40%. Public institutions and co-residential of urban areas were higher than others because of high area ratio of pervious land-cover. Spatial evaluation of water cycle was analyzed to vulnerable areas there are dense residential and commercial area. These areas are really occurring frequently flooding and immersion, therefore, is required water management facilities and improvement of land-cover from impervious to pervious. In the future, it will require additionally analysis of water cycle area ratio supplemented data of water management facility and ground water.

• 환경정책연구
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• 제7권3호
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• pp.121-140
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• 2008

불투수면 비율은 유역의 건전성 정도를 나타내는 중요한 척도로 활용되고 있으며 특히 유역의 수환경 특성을 파악하는 모델에서 이용되어 왔다. 불투수면은 총불투수면과 유효불투수면의 두 가지 있으며, 이들은 각 유역의 토지이용 특성에 따라 그 구성이 다양하다. 이중 총 불투수면은 기존의 토지이용도나 토지피복도를 사용하여 손쉽게 구할 수 있는 반면 유효불투수면은 물 흐름을 필지별로 파악하여야 하기 때문에 산정에 많은 노력과 비용이 소요된다. 본 연구에서는 우리나라 사례지역에 대해 총불투수면과 유효불투수면을 산정하여 그 특성을 상호 비교해 보고 유역관리에 있어 유효 및 총 불투수면 비율의 적용방안을 모색하고자 하였다. 사례지역 분석결과 유효불투수면 면적은 39.7%로 총 불투수면 면적 43%에 비해 약 3%적었다. 불투수면이 수환경에 미치는 영향을 분석하기 위한 기초 자료로 활용하기 위함임을 고려할 때 비용과 시간적 측면에서 볼 때 총불투수면을 유역의 대표적인 불투수면 비율로 사용할 수 있을 것으로 판단된다.

• 대기
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• 제21권4호
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• pp.405-414
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• 2011

In this study, the influence of a change in land use on the local weather fields is investigated around the Lake Shihwa area using synthetic land cover data and a high-resolution mesoscale model - the Weather Research and Forecasting (WRF). The default land cover data generally used in the WRF is based on the land use category of the United States Geological Survey (USGS), which erroneously presents most land areas of the Korean Peninsula as savannas. To revise such a fault, a multi-temporal land cover data, provided by the Ministry of Environment of Korea, was employed to generate a land cover map of 2005 subject to the land use in Korea at that time. A new land cover map of 1989, before the construction of the Lake Shihwa, was made based on the 2005 map and the Landsat 4-5 TM satellite images of two years. Over the areas where the land use had been changed (e.g., from sea to wetlands, towns, etc.) due to the Lake Shihwa development project, the skin temperature decreased by up to $8^{\circ}C$ in the winter case while increased by as much as $14^{\circ}C$ in the summer case. Changes in the water vapor mixing ratio were mostly affected by advection and topography in both seasons, with considerable increase in the summer case due to continuous sea breeze. Local decrease in water vapor occurred over high land use change areas and/or over downstream of such areas where alteration in wind fields were induced by changes in skin temperature and surface roughness at the areas of land use changes. The albedo increased by about 0.1% in the regions where sea was converted into wetland. In the regions where urban areas were developed, such as Songdo New Town and Incheon International Airport, the albedo increased by up to 0.16%.

• 대기
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• 제17권2호
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• pp.159-169
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• 2007

A comparison of the three land cover data sets (United States Geological Survey: USGS, International Geosphere Biosphere Programme: IGBP, and University of Maryland: UMd), derived from 1992-1993 Advanced Very High Resolution Radiometer(AVHRR) data sets, was performed over the Asian continent. Preprocesses such as the unification of map projection and land cover definition, were applied for the comparison of the three different land cover data sets. Overall, the agreement among the three land cover data sets was relatively high for the land covers which have a distinct phenology, such as urban, open shrubland, mixed forest, and bare ground (>45%). The ratios of triple agreement (TA), couple agreement (CA) and total disagreement (TD) among the three land cover data sets are 30.99%, 57.89% and 8.91%, respectively. The agreement ratio between USGS and IGBP is much greater (about 80%) than that (about 32%) between USGS and UMd (or IGBP and UMd). The main reasons for the relatively low agreement among the three land cover data sets are differences in 1) the number of land cover categories, 2) the basic input data sets used for the classification, 3) classification (or clustering) methodologies, and 4) level of preprocessing. The number of categories for the USGS, IGBP and UMd are 24, 17 and 14, respectively. USGS and IGBP used only the 12 monthly normalized difference vegetation index (NDVI), whereas UMd used the 12 monthly NDVI and other 29 auxiliary data derived from AVHRR 5 channels. USGS and IGBP used unsupervised clustering method, whereas UMd used the supervised technique, decision tree using the ground truth data derived from the high resolution Landsat data. The insufficient preprocessing in USGS and IGBP compared to the UMd resulted in the spatial discontinuity and misclassification.

• 대한지리학회지
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• 제39권5호
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• pp.786-803
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• 2004

최근, 다중 센서 영상과 GIS 주제도 정보를 이용한 토지 피복 분류에 대해 관심이 증가하고 있는 추세이다. 그러나. 분류에 필요한 효과적인 GIS 정보를 충분히 보유하고 있음에도 불구하고, 최대우도법(MLE) 같은 전통적인 방법은 기존의 컴퓨터 프로그램들이 GTS 자료를 제대로 다룰 수 없다는 이유로 유용한 정보의 이용에 제한을 받아 왔다. 본 연구에서는 다중 파장대 및 다중 시기 영상을 이용하여 새로운 영상 분류기법을 제안하고자 한다. 특히 MLE기법을 확대하여 다중 스펙트럼 영상 자료 및 토지 피복 분류 자료 등을 함께 사용할 수 있도록 하였다. 또한 파라미터가 데이터에서 추정되는 경우 우도비(LRE) 추정법이 오히려 더 적합할 수 있어서 LRE기법도 함께 사용하였다. 연구 지역은 서해안 안면도 지역이며, 자료는 Landsat ETM+ 영상과 Landsat TM 영상을 이용하여 만든 토지 피복도이다. 연구 결과. 제안된 방법은 단일 스펙트럼 자료를 사용하는 것보다 현저히 개선된 분류 정확도를 나타낸다. 즉, 개선된 분류 영상들은. MLE를 사용했을 때는 $6.2\%$, LRE를 사용했을 때는 $9.2\%$의 분류 정확도 개선을 보였다. 또한 본 연구는 제시된 알고리즘이 토지 피복 변화에 따른 그 지역의 변화 지역 추출도 가능할 것으로 판단된다. 향후 토지피복 분류 결과는 실 세계에서 보다 정확한 의사결정을 위한 보완적인 자료로써 유용하게 사용될 수 있을 것이라는 판단된다.