• Title/Summary/Keyword: Urban atmosphere

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Influences of Ice Microphysical Processes on Urban Heat Island-Induced Convection and Precipitation (얼음 미시물리 과정이 도시 열섬이 유도하는 대류와 강수에 미치는 영향)

  • Han, Ji-Young;Baik, Jong-Jin
    • Atmosphere
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    • v.17 no.2
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    • pp.195-205
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    • 2007
  • The influences of ice microphysical processes on urban heat island-induced convection and precipitation are numerically investigated using a cloud-resolving model (ARPS). Both warm- and cold-cloud simulations show that the downwind upward motion forced by specified low-level heating, which is regarded as representing an urban heat island, initiates moist convection and results in downwind precipitation. The surface precipitation in the cold-cloud simulation is produced earlier than that in the warm-cloud simulation. The maximum updraft is stronger in the cold-cloud simulation than in the warm-cloud simulation due to the latent heat release by freezing and deposition. The outflow formed in the boundary layer is cooler and propagates faster in the cold-cloud simulation due mainly to the additional cooling by the melting of falling hail particles. The removal of the specified low-level heating after the onset of surface precipitation results in cooler and faster propagating outflow in both the warm- and cold-cloud simulations.

Characteristics of and Affecting Factors on the Concentrations of Polycyclic Aromatic Hydrocarbons Associated with PM10in the Urban Atmosphere (도시 대기 중 PM10에 함유된 다환방향족탄화수소의 농도분포특성과 주요 영향인자)

  • 최진수;백성옥
    • Journal of Korean Society for Atmospheric Environment
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    • v.19 no.1
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    • pp.33-44
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    • 2003
  • The atmospheric concentrations of particulate polycyclic aromatic hydrocarbons (PAHs) associated with PM$_{10}$ were determined in Taegu metropolitan area. Sampling was undertaken every five days throughout one year period from 1993 to 1994 at four sites, representing a residential, a commercial, an industrial, and a sub-urban area, respectively. Benzo (e) pyrene, benzo (k) fluoranthene, and chrysene were found to be the most abundant com-pounds during the study period. The concentrations of benzo (a) pyrene, one of carcinogenic PAHs, ranged 2.0~4.8 ng/㎥ in winter and 0.5~1.5 ng/㎥ in summer season, indicating a marked seasonal variation. It was found that there were very similar patterns in the relative profiles of PM$_{10}$-bound PAH concentrations among the four sampling sites, while the absolute levels of each PAH were significantly different from each site. In addition, the patterns of summer to winter concentration ratios for each PAH were almost identical between the different sites. Despite difficulties due to the lack of good markers for specific sources in the target compounds, we were able to evaluate and describe the effects of vehicle emissions and space heatings, using relative profiles of PAHs, winter to summer (W/S) ratios, PAH-to-PAH ratios, and the result of principal component analysis. As a con-sequence, it was concluded that the vehicle emissions in urban and sub -urban areas are likely to be a major contributor for PAH loadings in the ambient atmosphere during the non-heating season, while the contributions of residential heating and local industrial oil burning emissions were highly significant in heating season.son.

A Study on the Outdoor Space Design for Urban Mini Schools (도심형 소규모 초등학교의 외부공간 계획방향에 관한 연구)

  • Rieh, Sun-Young;Kwon, Min-Sung
    • Journal of the Korean Institute of Educational Facilities
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    • v.20 no.2
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    • pp.33-42
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    • 2013
  • Due to the lack of available site in urban setting outdoor space in elementary schools are getting smaller and tend to be replaced by indoor spaces. Focusing on courtyard, piloti space and roof space, this study analyzed the current condition and usage of the outdoor spaces in the urban mini-schools based on the analysis of architectural drawing, interview, survey, and observation. Following issues are found for appropriate planning for outdoor spaces in the urban mini-schools. Firstly, roof space needs to be coordinated with the physical education and outdoor class curriculum and should be planned separately for quiet activities. Secondly, the piloti space should be planned as an independent space rather than a connection between classroom and outdoor space, with appropriate surveillance from teacher's space for the lower graders. Thirdly, courtyard space, typical space in urban mini school surrounded by densely arranged buildings, should be thermally controlled for outdoor class or resting with appropriate screen from noise to keep quiet atmosphere.

Beyond Net Zero - SOM's Urban Sequoia Building Concept and Technologies for Future, Regenerative Cities

  • Mina Hasman;Jiejing Zhou;Alice Guarisco;Nicholas Chan;Alessandro Beghini;Zhaofan Li;Michael Cascio;Yasemin Kologlu
    • International Journal of High-Rise Buildings
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    • v.12 no.2
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    • pp.121-128
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    • 2023
  • Cities cover only 3% of the planet's surface, yet they are responsible for more than 75% of the global emissions. Given the projected urban built area will double by 2060, the carbon emitted from cities will further increase. SOM proposes the Urban Sequoia concept, for buildings that go beyond 'net zero' and absorb carbon from the atmosphere. This concept combines multiple strategies, including the use of an optimised building form with a highly efficient structural system, modularized prefabrication techniques, holistic integration of facade, MEP and interiors' components, bio-based materials, and Direct Air Capture (DAC) technology, to reduce a 40-storey building's whole life cycle carbon emissions by more than 300% over a 100-year lifespan. Calculations of embodied carbon emissions are performed with SOM's in-house Environmental Analysis (EA) Tool to demonstrate the effectiveness of employing Urban Sequoia's design strategies in the design of new buildings using current technologies.

Effect of Tropical Atmosphere on Corrosion of Different Metals

  • Wijesinghe, Sudesh;Zixi, Tan
    • Corrosion Science and Technology
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    • v.16 no.6
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    • pp.273-277
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    • 2017
  • Atmospheric corrosion is clearly the most noticeable of all corrosion processes. A tremendous amount of economic losses are caused by atmospheric corrosion. Thus, it is imperative to know the level of atmosphere's aggressiveness or in other words "corrosivity", before designing or planning any corrosion prevention strategy. In Singapore, corrosivity values were not recorded earlier though the process of measurement and recording was prevalent in other countries. With an aim of filling this gap, three test sites were setup at three locations in Singapore to represent marine, industrial and urban atmospheres or their mixtures. Subsequently, corrosivity readings were measured and recorded according to ISO 9223:2012 for the first time in Singapore. Salient atmospheric constituents or parameters like time of wetness (TOW), $Cl^-$, $SO_2$, $NO_2$, $O_3$, and $HNO_3$ were measured at all sites over a period of time to categorize corrosivity of particular atmosphere. The effect of the atmosphere on corrosion of steel, Cu, Al, and Zn has also been investigated and quantified. "Estimated" and "determined" corrosivities were quantified and compared according to ISO 9223 standard. The study data along with final corrosivity measurements will be presented and discussed in the present work.

The Effect of Cafe Atmosphere on Purchase Decision: Empirical Evidence from Generation Z in Indonesia

  • BUDIMAN, Santi;DANANJOYO, Radyan
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.4
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    • pp.483-490
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    • 2021
  • In Indonesia, coffee shops, commonly called warung or kedai shops, have begun to appear amid society from remote villages to urban centers. Therefore, the purpose of this study is to examine the effect of cafe atmosphere (i.e., exterior, interior, interior point-of-purchase displays and store layout) on the purchase decision of Generation Z. This study is conducted because of cafe competition is currently overgrowing. This study model consisted of five variables: exterior, interior, interior point-of-purchase displays, store layout, and purchase decision. Sampling in this study used non-probability, with a purposive sampling technique. According to predetermined criteria, the data collection technique employed a questionnaire distributed online to consumers had visited a cafe at least once in the last three months. This study's sample was 137 cafe visitors in Yogyakarta, representing one of the big cities in Indonesia. Therefore, the data was analyzed by using multiple regression. The results of the study indicated that the exterior and interior had a positive and significant effect on purchasing decision. Likewise, interior point-of-purchase displays and store layout positively and significantly affected purchase decision. In addition, this study's findings generally concluded that the cafe atmosphere had a positive and significant effect on purchase decision.

Detection of Individual Trees in Human Settlement Using Airborne LiDAR Data and Deep Learning-Based Urban Green Space Map (항공 라이다와 딥러닝 기반 도시 수목 면적 지도를 이용한 개별 도시 수목 탐지)

  • Yeonsu Lee ;Bokyung Son ;Jungho Im
    • Korean Journal of Remote Sensing
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    • v.39 no.5_4
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    • pp.1145-1153
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    • 2023
  • Urban trees play an important role in absorbing carbon dioxide from the atmosphere, improving air quality, mitigating the urban heat island effect, and providing ecosystem services. To effectively manage and conserve urban trees, accurate spatial information on their location, condition, species, and population is needed. In this study, we propose an algorithm that uses a high-resolution urban tree cover map constructed from deep learning approach to separate trees from the urban land surface and accurately detect tree locations through local maximum filtering. Instead of using a uniform filter size, we improved the tree detection performance by selecting the appropriate filter size according to the tree height in consideration of various urban growth environments. The research output, the location and height of individual trees in human settlement over Suwon, will serve as a basis for sustainable management of urban ecosystems and carbon reduction measures.

Atmospheric Environment Prediction to Consider SST and Vegetation Effect in Coastal Urban Region (해수면온도와 식생효과를 고려한 연안도시지역의 대기환경예측)

  • Ji, Hyo-Eun;Lee, Hwa-Woon;Won, Gyeong-Mee
    • Journal of Environmental Science International
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    • v.18 no.4
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    • pp.375-388
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    • 2009
  • Numerical simulation is essential to indicate the flow of the atmosphere in the region with a complicated topography which consists of many mountains in the inland while it is neighboring the seashore. Such complicated topography produces land and sea breeze as the mesoscale phenomenon of meteorology which results from the effect of the sea and inland. In the mesoscale simulation examines, the change of the temperature in relation to the one of the sea surface for the boundary condition and, in the inland, the interaction between the atmosphere and land surface reflecting the characteristic of the land surface. This research developed and simulated PNULSM to reflect both the SST and vegetation effect as a bottom boundary for detailed meteorological numerical simulation in coastal urban area. The result from four experiments performed according to this protocol revealed the change of temperature field and wind field depending on each effect. Therefore, the lower level of establishment of bottom boundary suitable for the characteristic of the region is necessary to figure out the atmospheric flow more precisely, and if the characteristic of the surface is improved to more realistic conditions, it will facilitate the simulation of regional environment.

Sensitivity Analysis of Near Surface Air Temperature to Land Cover Change and Urban Parameterization Scheme Using Unified Model (통합모델을 이용한 토지피복변화와 도시 모수화 방안에 따른 지상 기온 모의성능 민감도 분석)

  • Hong, Seon-Ok;Byon, Jae-Young;Park, HyangSuk;Lee, Young-Gon;Kim, Baek-Jo;Ha, Jong-Chul
    • Atmosphere
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    • v.28 no.4
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    • pp.427-441
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    • 2018
  • This study examines the impact of the urban parameterization scheme and the land cover change on simulated near surface temperature using Unified Model (UM) over the Seoul metropolitan area. We perform four simulations by varying the land cover and the urban parameterization scheme, and then compare the model results with 46 AWS observation data from 2 to 9 August 2016. Four simulations were performed with different combination of two urban parameterization schemes and two land cover data. Two schemes are Best scheme and MORUSES (Met Office Reading Urban Surface Exchange Scheme) and two land cover data are IGBP (International Geosphere and Biosphere Programme) and EGIS (Environmental Geographic information service) land cover data. When land use data change from IGBP to EGIS, urban ratio over the study area increased by 15.9%. The results of the study showed that the higher change in urban fraction between IGBP and EGIS, the higher the improvement in temperature performance, and the higher the urban fraction, the higher the effect of improving temperature performance of the urban parameterization scheme. 1.5-m temperature increased rapidly during the early morning due to increase of sensible heat flux in EXP2 compared to CTL. The MORUSES with EGIS (EXP3) provided best agreement with observations and represents a reasonable option for simulating the near surface temperature of urban area.

Spectral Classification of Man-made Materials in Urban Area Using Hyperspectral Data

  • Kim S. H.;Kook M. J.;Lee K. S.
    • Proceedings of the KSRS Conference
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    • 2004.10a
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    • pp.10-13
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    • 2004
  • Hyperspectral data has a great advantage to classify various surface materials that are spectrally similar. In this study, we attempted to classify man-made materials in urban area using Hyperion data. Hyperion imagery of Seoul was initially processed to minimize radiometric distortions caused by sensor and atmosphere. Using color aerial photographs. we defined seven man-made surfaces (concrete, asphalt road. railroad, buildings, roof, soil, shadow) for the classification in Seoul. The hyperspectral data showed the potential to identify those manmade materials that were difficult to be classified by multispectral data. However. the classification of road and buildings was not quite satisfactory due to the relatively low spatial resolution of Hyperion image. Further, the low radiometric quality of Hyperion sensor was another limitation for the application in urban area.

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