• Title/Summary/Keyword: Urban climate changes

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Evaluation of Urban Effects on Trends of Hydrometeorological Variables (수문기상요소 추세에 대한 도시화 영향분석)

  • Rim, Chang-Soo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.1B
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    • pp.71-80
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    • 2010
  • This study aimed to figure out the effect of urbanization on meteorological variables (air temperature, wind speed, relative humidity, solar radiation and precipitation) and reference evapotranspiration (RET). The research area of 6 urban areas and 6 rural areas near each urban area was selected. The monthly average daily data were collected from 12 ground stations operated by Korea Meteorological Administration (KMA) and the changes in climate variables were analyzed. Results of annual analysis have shown that the reference evapotranspiration (RET) tends to increase in urban areas while decreasing in rural areas. In particular, due to rising RET in urban areas and decreasing RET in rural areas, we can infer that the urbanization has affected to the RET. Results of monthly analysis showed that the urbanization has effects on the RET of July compared to other months (January, April and October). The yearly and monthly effects of urbanization on RET were closely related to solar radiation, relative humidity and change in temperature, and related to wind speed.

Toward Net-Zero Energy Retrofitting: Building-Integrated Photovoltaic Curtainwalls

  • Kim, Kyoung Hee;Im, Ok-Kyun
    • International Journal of High-Rise Buildings
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    • v.10 no.1
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    • pp.35-43
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    • 2021
  • With the rapid urbanization and growing energy use intensity in the built environment, the glazed curtainwall has become ever more important in the architectural practice and environmental stewardship. Besides its energy efficiency roles, window has been an important transparent component for daylight penetration and a view-out for occupant satisfaction. In response to the climate crisis caused by the built environment, this research focuses on the study of net-zero energy retrofitting by using a new building integrated photovoltaic (BIPV) curtainwall as a sustainable alternative to conventional window systems. Design variables such as building orientations, climate zones, energy attributes of BIPV curtainwalls, and glazed area were studied, to minimize energy consumption and discomfort hours for three cities representing hot (Miami, FL), mixed (Charlotte, NC), and cold (Minneapolis, MN). Parametric analysis and Pareto solutions are presented to provide a comprehensive explanation of the correlation between design variables and performance objectives for net-zero energy retrofitting applications.

Change Projection of Extreme Indices using RCP Climate Change Scenario (RCP 기후변화시나리오를 이용한 극한지수 변화 전망)

  • Jeung, Se-Jin;Sung, Jang Hyun;Kim, Byung-Sik
    • Journal of Korea Water Resources Association
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    • v.46 no.11
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    • pp.1089-1101
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    • 2013
  • The study uses a regional climate model to check future changes in extreme climate, to calculate extreme indexes presented by STARDEX, and to analyze the trends to predict the continuity and changes in the spatial distribution of extreme climate in the future. An analysis of extreme climate indices showed that they are likely to increase in the Seoul metropolitan area, in Gyeonggi-do, in Yongdong in Gangwon-do, and in the southern shore region of Korea. It is, however, forecasted to diminish in the central inland region. The analysis also showed that the average temperature in Korea will increase because of climate change. On the other hand, an analysis of extreme rainfall indexes showed that the trend of heavy rainfall threshold is 0.229 in Seogwipo, the greatest five-day rainfall is 5.692 in Seogwipo, and the longest dry period is 0.099 in Sokcho. Of extreme temperature indexes, the trend of Hotdays threshold is 0.777 in Incheon and the longest heat wave is 0.162 in Uljin. The Coldnight threshold is 0.075 in Inje and -0.193 in Tongyeong, according to the analysis.

Impacts assessment of Climate changes in North Korea based on RCP climate change scenarios II. Impacts assessment of hydrologic cycle changes in Yalu River (RCP 기후변화시나리오를 이용한 미래 북한지역의 수문순환 변화 영향 평가 II. 압록강유역의 미래 수문순환 변화 영향 평가)

  • Jeung, Se Jin;Kang, Dong Ho;Kim, Byung Sik
    • Journal of Wetlands Research
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    • v.21 no.spc
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    • pp.39-50
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    • 2019
  • This study aims to assess the influence of climate change on the hydrological cycle at a basin level in North Korea. The selected model for this study is MRI-CGCM 3, the one used for the Coupled Model Intercomparison Project Phase 5 (CMIP5). Moreover, this study adopted the Spatial Disaggregation-Quantile Delta Mapping (SDQDM), which is one of the stochastic downscaling techniques, to conduct the bias correction for climate change scenarios. The comparison between the preapplication and postapplication of the SDQDM supported the study's review on the technique's validity. In addition, as this study determined the influence of climate change on the hydrological cycle, it also observed the runoff in North Korea. In predicting such influence, parameters of a runoff model used for the analysis should be optimized. However, North Korea is classified as an ungauged region for its political characteristics, and it was difficult to collect the country's runoff observation data. Hence, the study selected 16 basins with secured high-quality runoff data, and the M-RAT model's optimized parameters were calculated. The study also analyzed the correlation among variables for basin characteristics to consider multicollinearity. Then, based on a phased regression analysis, the study developed an equation to calculate parameters for ungauged basin areas. To verify the equation, the study assumed the Osipcheon River, Namdaecheon Stream, Yongdang Reservoir, and Yonggang Stream as ungauged basin areas and conducted cross-validation. As a result, for all the four basin areas, high efficiency was confirmed with the efficiency coefficients of 0.8 or higher. The study used climate change scenarios and parameters of the estimated runoff model to assess the changes in hydrological cycle processes at a basin level from climate change in the Amnokgang River of North Korea. The results showed that climate change would lead to an increase in precipitation, and the corresponding rise in temperature is predicted to cause elevating evapotranspiration. However, it was found that the storage capacity in the basin decreased. The result of the analysis on flow duration indicated a decrease in flow on the 95th day; an increase in the drought flow during the periods of Future 1 and Future 2; and an increase in both flows for the period of Future 3.

Impacts assessment of Climate change on hydrologic cycle changes in North Korea based on RCP climate change scenarios I. Development of Long-Term Runoff Model Parameter Estimation for Ungauged Basins (RCP 기후변화시나리오를 이용한 미래 북한지역의 수문순환 변화 영향 평가 I. 미계측유역의 장기유출모형 매개변수 추정식 개발)

  • Jeung, Se Jin;Kang, Dong Ho;Kim, Byung Sik
    • Journal of Wetlands Research
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    • v.21 no.spc
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    • pp.28-38
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    • 2019
  • Climate change on the Korean peninsula is progressing faster than the global average. For example, typhoons, extreme rainfall, heavy snow, cold, and heatwave that are occurring frequently. North Korea is particularly vulnerable to climate change-related natural disasters such as flooding and flooding due to long-term food shortages, energy shortages, and reckless deforestation and development. In addition, North Korea is classified as an unmeasured area due to political and social influences, making it difficult to obtain sufficient hydrologic data for hydrological analysis. Also, as interest in climate change has increased, studies on climate change have been actively conducted on the Korean Peninsula in various repair facilities and disaster countermeasures, but there are no cases of research on North Korea. Therefore, this study selects watershed characteristic variables that are easy to acquire in order to apply localization model to North Korea where it is difficult to obtain observed hydrologic data and estimates parameters based on meteorological and topographical characteristics of 16 dam basins in South Korea. Was calculated. In addition, as a result of reviewing the applicability of the parameter estimation equations calculated for the fifty thousand, Gangneungnamdaecheon, Namgang dam, and Yeonggang basins, the applicability of the parameter estimation equations to North Korea was very high.

Future Projection of Extreme Climate over the Korean Peninsula Using Multi-RCM in CORDEX-EA Phase 2 Project (CORDEX-EA Phase 2 다중 지역기후모델을 이용한 한반도 미래 극한 기후 전망)

  • Kim, Do-Hyun;Kim, Jin-Uk;Byun, Young-Hwa;Kim, Tae-Jun;Kim, Jin-Won;Kim, Yeon-Hee;Ahn, Joong-Bae;Cha, Dong-Hyun;Min, Seung-Ki;Chang, Eun-Chul
    • Atmosphere
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    • v.31 no.5
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    • pp.607-623
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    • 2021
  • This study presents projections of future extreme climate over the Korean Peninsula (KP), using bias-corrected data from multiple regional climate model (RCM) simulations in CORDEX-EA Phase 2 project. In order to confirm difference according to degree of greenhouse gas (GHG) emission, high GHG path of SSP5-8.5 and low GHG path of SSP1-2.6 scenario are used. Under SSP5-8.5 scenario, mean temperature and precipitation over KP are projected to increase by 6.38℃ and 20.56%, respectively, in 2081~2100 years compared to 1995~2014 years. Projected changes in extreme climate suggest that intensity indices of extreme temperatures would increase by 6.41℃ to 8.18℃ and precipitation by 24.75% to 33.74%, being bigger increase than their mean values. Both of frequency indices of the extreme climate and consecutive indices of extreme precipitation are also projected to increase. But the projected changes in extreme indices vary regionally. Under SSP1-2.6 scenario, the extreme climate indices would increase less than SSP5-8.5 scenario. In other words, temperature (precipitation) intensity indices would increase 2.63℃ to 3.12℃ (14.09% to 16.07%). And there is expected to be relationship between mean precipitation and warming, which mean precipitation would increase as warming with bigger relationship in northern KP (4.08% ℃-1) than southern KP (3.53% ℃-1) under SSP5-8.5 scenario. The projected relationship, however, is not significant for extreme precipitation. It seems because of complex characteristics of extreme precipitation from summer monsoon and typhoon over KP.

Which Environmental Factors Caused Lammas Shoot Growth of Korean Red Pine?

  • Lee, Chang-Seok;Song, Hye-Gyung;Kim, Hye-Soo;Lee, Bit-Na-Ra;Pi, Jeong-Hoon;Cho, Yong-Chan;Seol, Eun-Sil;Oh, Woo-Seok;Park, Sung-Ae;Lee, Seon-Mi
    • Journal of Ecology and Environment
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    • v.30 no.1
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    • pp.101-105
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    • 2007
  • Lammas growth, a rare phenomenon for Korean red pine (Pinus densiflora), occurred in 2006. Lammas shoots showed higher frequency and longer length in Seoul's hotter urban center than in urban boundary or suburban forest sites. Frequency and length showed a close correlation with urbanization density and vegetation cover expressed in NDVI. Air temperature in the late summer of 2006 was more than $1^{\circ}C$ higher than an average year. Of the predominant environmental signals that modulate bud flush, only temperature changed significantly during the year. Differences in temperature between the urban centers, urban boundaries and suburban forests correlated with varying land-use density. The rise in temperature likely spurred lammas growth of the Korean red pine. Symptoms of climate change are being detected throughout the world, and its consequences will be clearer in the future. Considerate interest in the responses of ecological systems to the variable changes is required to prepare for unforeseeable crises. Monitoring of diverse ecological phenomena at Long Term Ecological Research sites could offer harbingers of change.

The Numerical Prediction of the Micro Climate Change by a Residential Development Region

  • Oh, Eun-Joo;Lee, Hwa Woon;Kondo, Akira;Kaga, Akikazu;Yamaguchi, Katsuhito
    • Journal of Environmental Science International
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    • v.12 no.5
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    • pp.529-539
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    • 2003
  • We developed a numerical model that considered the influences on the thermal environment of vegetation, water surfaces and buildings to predict micro climatic changes in a few $\textrm{km}^2$ scales; and applied this model to the Mino residential development region in Osaka Prefecture by using a nested technique. The calculated temperatures and winds in the residential development region reasonably agreed with the observed ones. We then investigated the influences on the thermal environment of the construction of a dam, the change of the green coverage rate. The results obtained from the numerical simulations were qualitatively reasonable.

Analyzing Change of Discomfort Index for Transpiration of Street Tree (도시 가로수의 증산 작용으로 인한 불쾌지수 변화 분석)

  • Yun, Seok-Hwan;Lee, Dong-Kun;Park, Chae-Yeon
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.23 no.5
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    • pp.29-43
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    • 2020
  • Thermal environment of city is getting worse due to severe urban heat island caused by climate change and urbanization. The cooling effect of street tree is regarded as a effective way to ameliorate the urban heat environment. The effect is largely made up of shadow formation and transpiration. This study aims to identify how the transpiration affects the discomfort index by analyzing comprehensive impact of the transpiration on the air temperature and relative humidity. The changes in the amount of transpiration, air temperature, and relative humidity were estimated for Seogyo-dong area which has a lot of floating population in Seoul, at 2 p.m. in dry day in July and August. On average, the transpiration of the street tree decreased the temperature 0.3℃ and increased the relative humidity 2.6% in an hour. As a result of these changes in temperature and humidity, the discomfort index rose mostly(0.036 on average). It was always get rise especially on the day when the discomfort index was above 80(0.05 on average). However, compared with the significant change in temperature and humidity, the variation of the discomfort index itself was very slight(up to 0.107). Therefore, the effect of transpiration by the street trees might not be effective in the planning to improve the thermal environment(especially on the day when the discomfort index is high). It is necessary to select the species of trees and planting location considering the cooling effect of shade formation synthetically.