• 한국조경학회지
• /
• 제27권4호
• /
• pp.23-28
• /
• 1999

This study measured transpiration rate of urban trees and albedos of urban surfaces, and examined the function of microclimate amelioration by urban greenspace. Transpiration rates of trees were highest in July and August of growing months. Transpiration per unit leaf area for the two months was 300-350 g/$m^2$/h for Platanus occidentalis, 210-270 g/$m^2$/h for Ginkgo biloba and Zelkova serrata, and 130-140 g/$m^2$/h for Acer palmatum. Surface albedos were 0.09 for asphalt paving and 0.68 for white wall, which reveals that light-colored surfaces are better than dark-colored ones to lower the heat build-up. Due to lack of evapotranspiration, concrete surfaces were, at t midafternoon maximum, 8$^{\circ}C$ hotter than grass ones, though the albedo of concrete paving was higher thant that of grass and trees. Summer air temperatures at places with 12% and 22% cover of woody plants were, respectively, 0.6$^{\circ}C$ and 1.4$^{\circ}C$ cooler than a place with no vegetation. To mitigate the impacts of urban heat islands, required are minimization of hard surfaces, light-coloring for building surfaces, and greenspace enlargement including more plantings.

• 한국환경과학회지
• /
• 제24권6호
• /
• pp.819-826
• /
• 2015

This study measured temperatures and albedos of urban surfaces for different colors and materials during summer, and calculated the energy budget over different urban surfaces to find out the thermal performance affecting the heat built-up. The study selected six surface colors and 13 materials common in urban landscape. Their surface temperatures (Ts) and albedos were measured at a given time interval in the daytime from June to August. Average Ts over summer season for asphalt-colored brick was $4.0^{\circ}C$ higher than that for light red-colored one and $9.7^{\circ}C$ higher than that for white-colored one. The Ts for artificial surface materials of asphalt paving, brown brick wall, and green concrete wall was $6.0^{\circ}C$ higher than that for natural and semi-natural ones of grass, grassy block, and planted concrete wall. There was the greatest difference of $16.3^{\circ}C$ at midafternoon in the Ts between asphalt paving and planted concrete wall. Average albedo over summer season of surface materials ranged from 0.08 for asphalt paving to 0.67 for white concrete wall. This difference in the albedo was associated with a maximum of $15.7^{\circ}C$ difference at midafternoon in the Ts. Increasing the albedo by 0.1 (from 0.22 to 0.32) reduced the Ts by about $1.3^{\circ}C$. Average storage heat at midday by natural and semi-natural surfaces of grass and grassy block was about 10% lower than that by artificial ones of asphalt, light-red brick, and concrete. Reflected radiation, which ultimately contributes to heating the urban atmosphere, was 3.7 times greater for light-red brick and concrete surfaces than for asphalt surface. Thus, surfaces with in-between tone and color are more effective than dark- or white-colored ones, and natural or semi-natural surfaces are much greater than artificial ones in improving the urban thermal environment. This study provides new information on correlation between Ts and air temperature, relationship between albedo and Ts, and the energy budget.

• 대한원격탐사학회지
• /
• 제30권3호
• /
• pp.399-415
• /
• 2014

The intensity of stormwater runoff is particularly acute across cities located in arid climates. During flash floods loose sediment and pollutants are typically transported across sun-hardened surfaces contributing to widespread degradation of water quality. Rapid, dense urbanization exacerbates the problem by creating continuous areas of impervious surfaces, perforated only by a few green patches. Our work demonstrates how the latest techniques in remote sensing can be used to routinely measure urban land cover types, impervious cover, and vegetated areas. In addition, multiple regression models can then infer relationships between urban land use and land cover types with stormwater quality data, initially sampled at discrete monitoring sites, and then extrapolated annually across an arid city; in our case, the city of Phoenix in Arizona, USA. Results reveal that from 30 storm event samples, solids and heavy metal pollutants were found to be highly related with general impervious surfaces; in particular, with industrial and commercial land use types. Repercussions stemming from this work include support for public policies that advocate environmental sustainability and the more recent focus on urban livability. Also, advocacy for new urban construction and re-development that both steer away from vast unbroken impervious surfaces, in place of more fragmented landscapes that harmonize built and green spaces.

• International Journal of Advanced Culture Technology
• /
• 제4권2호
• /
• pp.1-6
• /
• 2016

Impervious surfaces are important indicators for urban development monitoring. Accurate mapping of urban impervious surfaces with observational satellites, such as VNREDSat-1, remains challenging due to the spectral diversity not captured by an individual PAN image. In this article, five multi-resolution image fusion techniques were compared for the task of classifting urban impervious surfaces. The result shows that for VNREDSat-1 dataset, UNB and Wavelet tranformation methods are the best techniques in reserving spatial and spectral information of original MS image, respectively. However, the UNB technique gives the best results when it comes to impervious surface classification, especially in the case of shadow areas included in non-impervious surface group.

• 한국물환경학회지
• /
• 제31권2호
• /
• pp.120-133
• /
• 2015

Due to increasing impervious surfaces resulting from urbanization and industrialization which are directly linked to urban inundation and non-point pollutants runoff, there is a need to manage them systematically. A management over urban impervious surfaces calls for pervious/impervious maps, which enable viewing the distribution of impervious surfaces. Nevertheless, relevant data are absent as now. In this respect, despite the diversity of proposed methods, pilot implementation and accuracy verification have never been conducted. Therefore, this study is aimed to produce a pilot pervious/impervious map based on previously proposed methods and to elucidate its pros and cons with a view to proposing a method for producing a GIS-based optimal pervious/impervious map. Following previously proposed methods, a pervious/impervious map of Bupyeong-gu, Incheon was produced. Then, a method of producing optimal pervious/impervious maps applicable to urban areas was proposed through the comparison of pros and cons of relevant spatial data. As a result, the map had been confirmed 99.2% of classification accuracy. Based on the present findings, future studies should establish a standardized method for producing. Also, this method should be used to produce pervious/impervious maps of other regions so that it can be applied to managing impervious surfaces in major urban areas nationwide.

• 대한원격탐사학회지
• /
• 제38권1호
• /
• pp.127-137
• /
• 2022

Urban Heat Island (UHI) effect has been widely studied as a global concern of the 21st century. Heat generation from urban built-up structures and anthropogenic heat sources are the main factors to create UHIs. Unfortunately, both factors are expanding rapidly in Lahore and accelerating UHI effects. The effects of UHI are expanding with the expansion of impermeable surfaces towards urban green areas. Therefore, this study was arranged to analyze the role of urban cooling intensity in reducing urban heat island effects. For this purpose, 15 parks were selected to analyze their effects on the land surface temperature (LST) of Lahore. The study obtained two images of Landsat-8 based on seasons: the first of June-2018 for summer and the second of November-2018 for winter. The LST of the study area was calculated using the radiative transfer equation (RTE) method. The results show that the theme parks have the largest cooling effect while the linear parks have the lowest. The mean park LST and PCI of the samples are also positively correlated with the fractional vegetation cover (FVC) and normalized difference water index (NDWI). So, it is concluded that urban parks play a positive role in reducing and mitigating LST and UHI effects. Therefore, it is suggested that the increase of vegetation cover should be used to develop impervious surfaces and sustainable landscape planning.

• 한국조경학회지
• /
• 제38권2호
• /
• pp.109-118
• /
• 2010

본 연구는 랜드스케이프 어바니즘을 적용한 도시재생적 실천전략을 모색하기 위해 연구되었다. 특히, 랜드스케이프 어바니즘을 산업사회를 넘어 지식정보산업사회의 도래와 함께 나타나는 도시화의 새로운 특성과 양상, 또 산업화시대의 신도시 이상을 넘어 도시재생이라는 새로운 도시 이상과의 상관성 맥락에서 도시재생에 어떻게 적용할 것인가의 관점에서 수행되었다. 본 연구의 결과, 랜드스케이프 어바니즘에서의 랜드스케이프의 의미가 도시를 대상으로 시각적, 장식적 차원의 정태적 풍경이 아니라, 변화, 진화 등의 맥락에서 동태적 과정을 대상으로 하고 있고, 지식정보산업사회가 지식 정보의 흐름 등 가속적 변화와 과정적 특징을 보이며, 이러한 사회적 특징에 따라 도시화도 형태와 기능 중심에서 흐름, 네트워킹, 중심성과 결절성, 지표면 등의 개념으로 구성되는 가치지향의 과정적, 동태적 특성을 보인다는 점에서 이들 3자간에는 그 본질적 개념에 있어 상호 관통되고 소통되고 있는 것으로 나타났다. 특히, 산업화시대의 도시화에 대한 반성으로서 21세기 새로운 도시이상으로서 대두되고 있는 도시재생은 본질적으로 아스팔트와 콘크리트로 점유된 도시 경관판을 그린 인프라 구축과 디자인이라는 맥락에서 생태판에 문화를 도입한 문화판으로 구축해야 한다는 당위성에서 랜드스케이프 어바니즘과 일정의 괘를 같이 하고 있었다. 본 연구에서 제시된 랜드스케이프 어바니즘을 적용한 8개의 도시재생전략으로는 도시가 자연과 역동적으로 소통하고 진화할 수 있는 생태판의 구축, 생태와 도시민과의 소통을 위한 생태판의 문화판으로의 전환, 주택 및 상업지역에서의 그린 인프라 구축 등의 관점에서, 건폐율 규제, 높이 규제 완화 등의 필요성이 제시 되었다. 또한, 도시이전적지의 공원화, 하천 등 도시워터프론트의 공원화 등의 전략에서 공원의 도시적 관입 및 확산과 더불어 공원혼합용도에 대한 도입이 논의되었다. 이러한 새로운 경관판을 형성하기 위한 실행전략으로 사회의 변화에 역동적으로 부응할 수 있는 전략계획제의 도입이 논의되었고, 특히, 이미지니어링을 통한 가치계획을 추구함으로써 기능중심의 도시화에서 가치창출과 브랜드형성 차원의 도시화로 진화시켜 나아가야 할 것을 제시하였다. 이 모든 전략을 위해 기존의 경관, 토지이용 등 건축 및 도시개발 관련 각종 제도가 개선되어야 할 것으로 제안되었다.

• 한국환경복원기술학회지
• /
• 제26권1호
• /
• pp.47-59
• /
• 2023

Due to climate change and urbanization, abnormally high temperatures and heat waves are expected to increase in urban and deteriorate thermal comfort. Planting of street trees and changing the albedo of urban surfaces are the strategies for mitigating the thermal environment of urban, and both of these strategies affect the exposure and blocking of radiative fluxes to pedestrians. After measuring the shortwave and longwave radiation according to the ground surface with different albedo and the presence of street trees using the CNR4 net radiometer, this study analyzed the relationship between this two strategies in terms of thermal environment mitigation by calculating the MRT(Mean Radiant Temperature) of each environment. As a result of comparing the difference between the downward shortwave radiation measured under the right tree and at the control, the shortwave radiation blocking effect of the tree increased as the downward shortwave radiation increased. During daytime hours (from 11 am to 3 pm), the MRT difference caused by the albedo difference(The albedo of the surfaces are 0.479 and 0.131, respectively.) on surfaces with no tree is approximately 3.58℃. When tree is present, the MRT difference caused by the albedo difference is approximately 0.49℃. In addition, in the case of the light-colored ground surface with high albedo, the surface temperature was low and the range of temperature change was lower than the surrounding surface with low albedo. This result shows that the urban thermal environment can be midigate through the planting of street trees, and that the ground surface with high albedo can be considered for short pedestrians. These results can be utilized in planning street and open space in urban by choosing surfaces with high albedo along with the shading effect of vegetation, considering the use by various users.

• 한국환경복원기술학회지
• /
• 제21권6호
• /
• pp.1-13
• /
• 2018

Mapping radiation heat flux of urban area is essential for urban design and landscape planning. Because controlling urban geometry and generating green space are important urban design strategies for reducing urban heat, urban planner and designer need to recognize the micro urban heat distribution for adequate urban planning. This study suggests a new methodology for mapping urban radiation heat flux in a micro scale considering buildings and trees' shade. For doing that, firstly, we calculate net radiation for each urban surfaces (building, road (not shaded, building shaded, tree shaded), ground (not shaded, building shaded, tree shaded), tree (not shaded, building shaded)). Then, by multiplying the area ratio of surfaces to the net radiation, we can obtain the radiation heat flux in micro-scale. The estimated net radiation results were found to be robust with a $R^2$ of 90%, which indicates a strong explanatory power of the model. The radiation heat flux map for 12h $17^{th}$ August explains that areas under the building and tree have lower net radiation heat flux, indicating that shading is a good strategy for reducing incident radiation. This method can be used for developing thermal friendly urban plan.

• 대한원격탐사학회지
• /
• 제23권6호
• /
• pp.529-536
• /
• 2007

불투수도는 도시화, 환경변화를 추정하기 위한 중요한 지수로서 도시 기후 변화, 홍수기철 도시 범람의 증가, 홍수 모델링에 영향 등 도시의 홍수 기상학과 수문학적인 변화와 매우 밀접한 관계가 있다. 본 연구에서는 안성지역 일대를 대상으로 하여 Landsat ETM+ 영상을 이용한 불투수도 작성을 시도하였다. 학습 및 검수자료는 고해상도 영상인 IKONOS 영상을 이용하였으며, Landsat ETM+ 영상에 대한 위성반사율을 이용하여 tasseled cap과 NDVI로 전환하고 다양한 변수들이 불투수도에 미치는 영향을 분석하였다. 그리고 Regression Tree 알고리즘에 따라 불투수도 추정식을 개발하여 지도화하였다.