• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
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• pp.21-25
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• 2009

This study is about heat island as one of the urban climate variation factors in urbanized modern society, which compared and observed the thermal characteristics both the downtown location and the outskirt site in summer. The diurnal air temperature range at each point is $12.6^{\circ}C$ in the downtown location and $14.3^{\circ}C$ in the outskirt site, so, it was found that the diurnal air temperature range in the outskirt site was $1.7^{\circ}C$ higher than in the downtown location. There was 20 minutes difference to reach the highest temperature between globe temperature and air temperature in the downtown location, however, the time spent to reach the highest temperature between globe temperature and air temperature in the outskirt site was the same. When we compared the globe temperature between the downtown location and outskirt site, we found that the temperature in the outskirt site was lower than in the downtown location after sunset due to the sudden temperature drops, although the exposed time to insolation in the outskirt site is longer. The average of globe temperature difference on the sample days was $1.1^{\circ}C$, the average of surface temperature difference on the sample days was $1.0^{\circ}C$, and the average of air temperature difference on the sample days was $2.0^{\circ}C$ Thus, it was found that the average of air temperature difference was higher than the average of globe temperature and the average of surface temperature. The result of this study is that the urban environment factors have more effect on the air temperature difference than globe temperature and surface temperature.

• 한국태양에너지학회 논문집
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• 제31권3호
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• pp.133-144
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• 2011

The objective of this study is to analyze the characteristic of radiation environment in the urban and rural through the field observation in the summer. The radiation balance was compared through the measurement of the shortwave radiation and long-wave radiation in the urban, sub-urban, and rural. The following conclusion could be obtained from this research. (1)In the results of observation including the rain-day, it was found that the short wave radiance in the urban is lower about 10% than the rural. (2)The upper part of atmosphere layers in the urban are aabsorb much short wave radiation energies compared with the rural relatively. It can increase the temperature of the upper part of atmosphere layers and the emittance of long wave radiation. (3)The ratio of the downward short wave radiation to the downward long wave radiation was 1.24 for the urban, 1.28 for sub-urban and 1.35 for rural. It can be estimated that the atmosphere condition of the rural is better than that of other areas. (4)The net radiation of the rural was lower that of the urban. It was found that the energy in and outflow of the rural is easier than that of the urban. (5)The temperature variation for the long-wave radiation change of the rural showed more sensitive than that of the urban. It was came from the radiation characteristics of the surrounding environment and can be used as the important index to evaluate the thermal environment characteristic of urban.

• 한국환경과학회지
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• 제25권11호
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• pp.1475-1484
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• 2016

To analyze the cooling effect of urban green areas, we conducted micrometeorological measurements in these areas and their surroundings in Seoul, Korea. From the average hourly temperature measurements through each month for the last two years (March 2013 to February 2015), we found that the maximum temperature difference between urban and green areas was about $2.9^{\circ}C$ at 16:00 LST in summer, and the minimum was about $1.7^{\circ}C$ at 22:00 LST in winter. In summer, the temperature difference was the largest during the day, rather than at night, due mainly to shading by the tree canopy. The specific humidity difference between the two areas was about $1.5g\;kg^{-1}$ in summer, and this decreased in the winter. The specific humidity difference between urban and green areas in summer is relatively large during the day, due to the higher evapotranspiration level of biologically active plants.

• 대한원격탐사학회지
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• 제36권4호
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• pp.609-626
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• 2020

Satellite-based land surface temperature (LST) has been used as one of the major parameters in various climate and environmental models. Especially, Moderate Resolution Imaging Spectroradiometer (MODIS) LST is the most widely used satellite-based LST product due to its spatiotemporal coverage (1 km spatial and sub-daily temporal resolutions) and longevity (> 20 years). However, there is an increasing demand for LST products with finer spatial resolution (e.g., 10-250 m) over regions such as urban areas. Therefore, various methods have been proposed to produce high-resolution MODIS-like LST less than 250 m (e.g., 100 m). The purpose of this review is to provide a comprehensive overview of recent research trends and challenges for the downscaling of MODIS LST. Based on the recent literature survey for the past decade, the downscaling techniques classified into three groups-kernel-driven, fusion-based, and the combination of kernel-driven and fusion-based methods-were reviewed with their pros and cons. Then, five open issues and challenges were discussed: uncertainty in LST retrievals, low thermal contrast, the nonlinearity of LST temporal change, cloud contamination, and model generalization. Future research directions of LST downscaling were finally provided.

• 한국도시철도학회논문집
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• 제6권4호
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• pp.243-248
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• 2018

전동차 하부전장품의 이상 고온은 열차 사고와 직결되며, 이에 대한 모니터링은 전동차의 안전운행을 위해 매우 중요하다. KTX 경우 차축의 이상 유무를 감지하고, 도시철도에서는 하부전장품의 온도를 스캔하는 이상검지장치가 선로변에 설치되어 이상발열이 발생할 경우 이를 검지하여 관제센터에 자동으로 알려주는 시스템이 설치되어 운영되고 있다. 시스템 구성은 비접촉식인 적외선 방사온도계가 필수적으로 사용되고 있다. 이 시스템에 사용되는 적외선 방사온도계는 빠른 응답성과 정확도가 생명이다. 본 논문에서는 온도계의 고속 응답성 검증방법에 대한 연구를 수행하였고, 실험 설비 제작을 통해서 데이터를 수집하여 응답성 검증 방법을 연구하였다.

• Ecology and Resilient Infrastructure
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• 제3권4호
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• pp.315-321
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• 2016

본 연구에서는 도시 토지이용과 열 환경의 관계를 파악하기 위하여, 인천시에서 토지이용이 다른 곳에서 기온을 측정하였고, 지난 40년간 토지이용과 기온의 변화를 파악하였으며, 위성영상 자료를 이용하여 토지이용과 온도의 관계에 대하여 연구하였다. 2014년 8월 19일부터 21일까지 산림지, 경작지 (논), 나지 (운동장), 시가화지 (아스팔트 도로)에서 온도를 측정한 결과에서 시가화지역이 가장 기온이 높았고 산림지가 가장 낮았다. 인천시에서 1975년부터 2014년까지 40년간 기온은 약 $1.4^{\circ}C$ ($0.035^{\circ}C$/년)이 상승하였다. 지난 40년간 인천시의 토지이용 유형에서 시가화건조지, 나지, 초지가 증가하였고 경작지, 습지, 산림지가 감소하였다. Landsat 위성영상을 이용하여 추출한 지표면 온도 (LST)와 정규식생지수 (NDVI), 정규시가지화지수 (NDBI) 간에 상관관계를 보였다. 지표면 온도는 NDVI가 높은 곳에서 지면온도가 낮았고, NDBI가 높은 곳에서 지면 온도가 높았다. 따라서 도시의 열섬효과를 완화하고 열 환경을 개선하기 위해서는 녹지, 습지, 농경지의 토지이용을 보전하고 복원하는 것이 중요하다고 판단된다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.1943-1947
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• 2007

The objective of this research was to find a direct and indirect method to estimate land surface temperature (LST) efficiently, using Landsat images and in-situ measurement. Agricultural fields including paddy fields have long been known to have multi-functions beneficial to the environment and ecology of the urban surrounding areas. Among these functions, the ambient temperature cooling (ATC) effect are widely acknowledged. However, quantitative and regional assessment of such effect has not had many investigations. Thermal remote sensing has been used over urban areas to assess ATC effect, to perform land cover classifications and as input for models of urban surface atmosphere exchange. Here, we review the use of thermal remote sensing in the study of paddy fields and urban climates, focusing primarily on the ATC effect. Landsat satellite images were used to determine the surface temperatures of different land cover types of a $441km^2$ study area in Cheongju, Korea. The results show that the ATC are a function of paddy area percentage in Landsat pixels. Pixels with higher paddy area percentage have more significant cooling effect.

• 한국주거학회논문집
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• 제22권3호
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• pp.25-33
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• 2011

Recently, concerns about conserving proper size of urban green spaces and accessibility are increasing, regarding it as a solution to diverse urban environmental problems including pollution, ecosystem deterioration, urban climate change. Artificial ground greening such as green roofs is regarded as the only alternative that can conserve green spaces which are impossible to be secured on the ground. However, green roofs are not popularized yet and levels are very low in provincial cities despite of related technology development and support systems of related agencies. Based on the background, this study tries to present a theoretical basis of methods for green roofs, conducting green roof simulations Finally, it aims to offer base data which help establish policy direction for activation of green roof technology. As a result of a simulation for verifying temperature reduction effect, it was possible to affirm effect of a plot that green roofs applied. Especially, it was revealed that a green roof method using ground covers such as mixed planting was the most effective way to reduce temperature. Based on precise analysis of the users, actual study for activation of green roofs should be developed in the future, by presenting a standard model for experiments and obtaining information about examples of green roofs on private houses.

• 한국환경생태학회지
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• 제32권1호
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• pp.97-104
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• 2018

본 연구는 산림 우점식생 변화가 지표면 온도에 미치는 영향을 파악하고자 우리나라 대표적 혹서지역인 대구광역시를 대상으로 연구를 수행하였다. 산림 우점식생 변화 유형별 온도변화는 1990년과 2007년의 Landsat TM 영상 2scene을 분석하여 확인하였다. 토지피복유형은 산림지역, 시가화지역, 경작지 및 기타지역, 수역으로 구분하였고, 산림지역의 경우 침엽수와 활엽수로 구분하였다. 산림 우점식생 변화 유형에 따른 지표면 온도 변화를 확인하기 위해 통계분석을 실시한 결과 산림이 시가화지역으로 변화될 경우 온도는 높아지며, 유형별로 살펴보면 활엽수림이 시가화지역으로 변화된 경우 약 $0.6^{\circ}C$, 침엽수림이 시가화지역으로 변화된 경우 약 $0.2^{\circ}C$ 온도가 상승하는 것을 확인할 수 있었다. 이는 단순히 17년간 유형변화에 따른 온도 차이로 현재까지 유형이 유지된 경우와 변화된 경우를 동시에 고려할 경우 온도는 더 높은 차이를 보였다. 활엽수림의 경우 활엽수림이 유지될 때 보다 시가화지역으로 변화 될 경우 온도는 $2.3^{\circ}C$ 증가하였으며, 침엽수림의 경우 침엽수림이 유지될 때 보다 시가화지역으로 변화될 경우 $1.9^{\circ}C$ 온도가 증가하였다. 산림의 경우 시가화지역으로 변화될 때 온도가 상승하며 산림식생유형 중 침엽수가 파괴되었을 경우보다 활엽수가 파괴되었을 때 $0.4^{\circ}C$ 온도가 추가적으로 상승하는 것으로 나타났다. 도시기온 완화를 위해서는 도시림 내에서 활엽수림의 보호가 더 효율적인 것으로 확인되었다.

• 한국조경학회지
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• 제30권3호
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• pp.25-34
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• 2002

The purpose of this paper is to discuss the function of microclimate amelioration of urban trees regarding the environmental benefits of street trees in summer, focusing on the heat pollution-urban heat island, tropical climate day's phenomenon and air pollution. We measured the diurnal variation of air/ground temperatures and humidity within the vegetation canopy with the meteorological tower observation system. Summertime air temperatures within the vegetation canopy layer were 1-2$^{\circ}C$ cooler than in places with no vegetation. Due to lack of evaporation, the ground surface temperatures of footpaths were, at a midafternoon maximum, 8$^{\circ}C$ hotter than those under trees. This means that heat flows from a place with no vegetation to a vegetation canopy layer during the daytime. The heat is consumed as a evaporation latent heat. These results suggest that the extension of vegetation canopy bring about a more pleasant urban climate. Diurnal variation of air/ground temperatures and humidity within the vegetation canopy were measured with the meteorological tower observation system. According to the findings, summertime air temperatures under a vegetation canopy layer were 1-2$^{\circ}C$ cooler than places with no vegetation. Due mainly to lack of evaporation the ground surface temperature of footpaths were up to 8$^{\circ}C$ hotter than under trees during mid-afternoon. This means that heat flows from a place where there is no vegetation to another place where there is a vegetation canopy layer during the daytime. Through the energy redistribution analysis, we ascertain that the major part of solar radiation reaching the vegetation cover is consumed as a evaporation latent heat. This result suggests that the expansion of vegetation cover creates a more pleasant urban climate through the cooling effect in summer. Vegetation plays an important role because of its special properties with energy balance. Depended on their evapotranspiration, vegetation cover and water surfaces diminish the peaks of temperature during the day. The skill to make the best use of the vegetation effect in urban areas is a very important planning device to optimize urban climate. Numerical simulation study to examine the vegetation effects on urban climate will be published in our next research paper.