• Journal of the Korean Institute of Landscape Architecture
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• v.50 no.1
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• pp.68-77
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• 2022

The human thermal environment in an apartment complex located in Seoul was quantitatively analyzed to devise methods to modify human heat-related stresses in landscape and urban planning. Microclimatic data (air temperature, relative humidity, wind speed, and short- and long-wave radiation) were collected at 6 locations [Apt-center, roof (cement), roof (grass), ground, playground, and a tree-lined road] in the late spring and summer, and the data were used to estimate the human thermal sensation, physiological equivalent temperature (PET) and universal thermal climate index (UTCI). As a result, the playground location had the highest thermal environment, and the roof (grass) location had the lowest. The mean difference between the two locations was 0.8-1.1℃ in air temperature, 1.8-4.0% in relative humidity, and 7.5-8.0℃ in mean radiant temperature. In open space locations, the wind speed was 0.4-0.5 ms-1 higher than others. Also, a wind tunnel effect happened at the Apt-center location during the afternoon. For the human thermal sensation, PET and UTCI, the mean differences between the playground and roof (grass) locations were: 5.2℃ (Max. 11.7℃) in late spring and 5.4℃ (Max. 18.1℃) in summer in PET; and 3.0℃ (Max. 6.1℃) in late spring and 2.6℃ (Max. 9.8℃) in summer in UTCI. The mean differences indicated a level change in PET and 1/2 level in UTCI, and the maximum differences showed greater changes, 2-3 levels in PET, and 1-1.5 levels in UTCI. Moreover, the roof (grass) location gave 4.6℃ PET reduction and a 2.5℃ UTCI reduction in late spring, and a 4.4℃ PET reduction and a 2.0℃ UTCI reduction in the summer when compared with the roof (cement) location, which results in a 2/3 level change in PET and a 1/3 level in UTCI. Green infrastructure locations [roof (grass), ground, and a tree-lined road] were not statistically significant in the reduction of PET and UTCI in thermal environment modifying effects. The implementation of green infrastructure, such as rooftop gardens, grass pavement, and street tree planting, should be adopted in landscape planning and be employed for human thermal environment modification.

• Journal of the Korean Institute of Landscape Architecture
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• v.50 no.2
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• pp.1-22
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• 2022

The modification effects of street trees on outdoor thermal comfort in summertime according to tree planting types and road direction were analyzed using a computer simulation program, ENVI-met. With trees, the air temperature and wind speed decreased, and the relative humidity increased. In the case of mean radiant temperature (T_mrt) and human thermal sensation, physiological equivalent temperature (PET) and universal thermal climate index (UTCI), there was a decrease during the daytime. The greatest change among the meteorological factors by trees happened in Tmrt, and PET and UTCI showed similar patterns with T_mrt·The most effective tree planting type on thermal comfort modification was low tree height, wide tree crown, high leaf area index, and narrow planting interval (LWDN). T_mrt, PET and UTCI showed a large difference depending on shadow patterns of buildings and trees according to solar altitude and azimuth angles, and building locations. When the building shade areas increased, the thermal modification effect by trees decreased. In particular, results on the east and west sidewalks showed a large deviation over time. When applying the LWDN, the northwest, west and southwest sidewalks showed a significant reduction of 8.6-12.3℃ PET and 4.2-4.5℃ UTCI at 10:00, and the northeast, east and southeast sidewalks showed 8.1-11.8℃ PET and 4.4-5.0℃ UTCI at 16:00. On the other hand, when the least effective type (high tree height, narrow tree crown, low leaf area index, and wide planting interval) was applied, the maximum reduction was up to 1.8℃ PET and 0.9℃ UTCI on the eastern sidewalks, and up to 3.0℃ PET and 0.9℃ UTCI on the western ones. In addition, the difference in modification effects on T_mrt, PET and UTCI between the tree planting types was not significant when the tree effects were reduced by the effects of buildings. These results can be used as basic data to make the most appropriate street tree planting model for thermal comfort improvement in urban areas in summer.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.6
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• pp.115-125
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• 2017

This study was to investigate the user's thermal environments under the pergola($L\;7,200{\times}W\;4,200{\times}H\;2,700mn$) covered with Wisteria floribunda(Willd.) DC. according to the variation of leaf area index(LAI). We carried out detailed measurements with two human-biometeorological stations on a popular square Jinju, Korea($N35^{\circ}10^{\prime}59.8^{{\prime}{\prime}}$, $E\;128^{\circ}05^{\prime}32.0^{{\prime}{\prime}}$, elevation: 38m). One of the stations stood under a pergola, while the other in the sun. The measurement spots were instrumented with microclimate monitoring stations to continuously measure air temperature and relative humidity, wind speed, shortwave and longwave radiation from the six cardinal directions at the height of 0.6m so as to calculate the Universal Thermal Climate Index(UTCI) from $9^{th}$ April to $27^{th}$ September 2017. The LAI was measured using the LAI-2200C Plant Canopy Analyzer. The analysis results of 18 day's 1 minute term human-biometeorological data absorbed by a man in sitting position from 10am to 4pm showed the following. During the whole observation period, daily average air temperatures under the pergola were respectively $0.7{\sim}2.3^{\circ}C$ lower compared with those in the sun, daily average wind speed and relative humidity under the pergola were respectively 0.17~0.38m/s and 0.4~3.1% higher compared with those in the sun. There was significant relationship in LAI, Julian day number and were expressed in the equation $y=-0.0004x^2+0.1719x-11.765(R^2=0.9897)$. The average $T_{mrt}$ under the pergola were $11.9{\sim}25.4^{\circ}C$ lower and maximum ${\Delta}T_{mrt}$ under the pergola were $24.1{\sim}30.2^{\circ}C$ when compared with those in the sun. There was significant relationship in LAI, reduction ratio(%) of daily average $T_{mrt}$ compared with those in the sun and was expressed in the equation $y=0.0678{\ln}(x)+0.3036(R^2=0.9454)$. The average UTCI under the pergola were $4.1{\sim}8.3^{\circ}C$ lower and maximum ${\Delta}UTCI$ under the pergola were $7.8{\sim}10.2^{\circ}C$ when compared with those in the sun. There was significant relationship in LAI, reduction ratio(%) of daily average UTCI compared with those in the sun and were expressed in the equation $y=0.0322{\ln}(x)+0.1538(R^2=0.8946)$. The shading by the pergola covered with vines was very effective for reducing daytime UTCI absorbed by a man in sitting position at summer largely through a reduction in mean radiant temperature from sun protection, lowering thermal stress from very strong(UTCI >$38^{\circ}C$) and strong(UTCI >$32^{\circ}C$) down to strong(UTCI >$32^{\circ}C$) and moderate(UTCI >$26^{\circ}C$). Therefore the pergola covered with vines used for shading outdoor spaces is essential to mitigate heat stress and can create better human thermal comfort especially in cities during summer. But the thermal environments under the pergola covered with vines during the heat wave supposed to user "very strong heat stress(UTCI>$38^{\circ}C$)". Therefore users must restrain themselves from outdoor activities during the heat waves.

• Journal of the Korean Association of Geographic Information Studies
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• v.27 no.2
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• pp.61-77
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• 2024

The purpose of this study was to develop a method for rapidly diagnosing urban thermal comfort using Unmanned Aerial Vehicle (UAV) based data. The research was conducted at Changwon National University's College of Engineering site and Yongji Park, both located in Changwon, Gyeongsangnam-do. Baseline data were collected using field measurements and UAVs. Specifically, the study calculated field measurement-based thermal comfort indices PET and UTCI, and used UAVs to create and analyze vegetation index (NDVI), sky view factor (SVF), and land surface temperature (LST) images. The results showed that UAV-predicted PET and UTCI had high correlations of 0.662 and 0.721, respectively, within a 1% significance level. The explanatory power of the prediction model was 43.8% for PET and 52.6% for UTCI, with RMSE values of 6.32℃ for PET and 3.16℃ for UTCI, indicating that UTCI is more suitable for UAV-based thermal comfort evaluation. The developed method offers significant time-saving advantages over traditional approaches and can be utilized for real-time urban thermal comfort assessment and mitigation planning

• Korean Journal of Environment and Ecology
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• v.28 no.1
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• pp.80-89
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• 2014

This study of the school's outdoor space for relaxing and activity of the two most numerous students, high heat and low heat with a green space, playground targets of thermal comfort indicators UTCI, PMV, WBGT using the thermal comfort students feeling compare the analyzed. The destination of this study, school facilities of Nam-gu, Namdong- gu, Incheon were studied and the investigation period was conducted from July to August. List of measurement, in the case of thermal comfort indicators, UTCI, PMV, WBGT was measured in the case of green, ratio of green coverage and GVZ was measured. GVZ analysis were as follows: A school ($4.71m^3/m^2$) B school ($3.34m^3/m^2$) C school ($0.38m^3/m^2$). Comparative analysis of the results of thermal comfort indicators by schools, UTCI was Green space $26.15{\sim}31.38^{\circ}C$ and playground $40.66{\sim}42.94^{\circ}C$, PMV values were 1.76 to 2.66 as a green space. WBGT was Green space $26.15{\sim}31.38^{\circ}C$, playground $31.67{\sim}34.53^{\circ}C$. Comparative analysis of the results of thermal comfort indicators UTCI, PMV, WBGT all A school, B school, C school, on the green space was comfortable levels more than playground. The results of the school type thermal comfort and green correlation analysis of thermal comfort UTCI, PMV, WBGT all solar radiation, globe temperature, and a positive correlation shown solar radiation, globe temperature is not comfortable, the higher was considered. UTCI, PMV, WBGT of thermal comfort indicator all ratio of green coverage, GVZ and negative correlation appears ratio of green coverage, GVZ was increased due to the lowering of the value of thermal comfort indicators was considered to be comfortable.

• Ecology and Resilient Infrastructure
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• v.7 no.1
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• pp.43-52
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• 2020

For investigating restriction in the use of computer modeling results without adjusting them with measured data, this study analyzed and compared microclimatic aspects and human thermal sensation between in situ measurement and computer modeling using ENVI-met in and around a small urban park of downtown Changwon in May, 2012. In the results, ENVI-met underestimated air temperatures and wind speeds than the measured ones and overestimated relative humidities. In the radiation analysis, ENVI-met overestimated solar radiation from the sky hemisphere and terrestrial radiation from the ground hemisphere and underestimated terrestrial radiation from the sky hemisphere. Also, the differences of mean radiant temperatures with the measured ones reached up to 19.6℃ which could create an 1.2 PMV difference. ENVI-met overestimated up to 2.3 PMV and 4℃ UTCI at 12:00. The difference was shown clearly in PMV than in UTCI. Therefore, when computer modeling is used in urban microclimate and human thermal sensation (comfort) studies the modeling results should be compared with measured data and adjusted adequately to adopt the results to urban and landscape planning and design.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.6
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• pp.73-85
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• 2015

This study investigated the extent and magnitude of the woodland edge effects on users' thermal environments according to distance from woodland border. A series of experiments to measure air temperature, relative humidity, wind velocity, MRT and UTCI were conducted over six days between July 31 and August 5, 2015, which corresponded with extremely hot weather, at the south-facing edge of Hadongsongrim(pure Pinus densiflora stands, tree age: $100{\pm}33yr$, tree height: $12.8{\pm}2.7m$, canopy closure: 75%, N $35^{\circ}03^{\prime}34.7^{{\prime}{\prime}}$, E $127^{\circ}44^{\prime}43.3^{{\prime}{\prime}}$, elevation 7~10m) and east-facing edge of Hamyangsangrim (Quercus serrata-Carpinus tschonoskii community, tree age: 102~125yr/58~123yr, tree height: tree layer $18.6{\pm}2.3m/subtree$ layer $5.9{\pm}3.2m/shrub$ layer $0.5{\pm}0.5m$, herbaceous layer coverage ratio 60%, canopy closure: 96%, N $35^{\circ}31^{\prime}28.1^{{\prime}{\prime}}$, E $127^{\circ}43^{\prime}09.8^{{\prime}{\prime}}$, elevation 170~180m) in rural villages of Hadong and Hamyang, Korea. The minus result value of depth means woodland's outside. The depth of edge influence(DEI) on the maximum air temperature, minimum relative humidity and wind speed at maximum air temperature time during the daytime(10:00~17:00) were detected to be $12.7{\pm}4.9$, $15.8{\pm}9.8$ and $23.8{\pm}26.2m$, respectively, in the mature evergreen conifer woodland of Hadongsongrim. These were detected to be $3.7{\pm}2.2$, $4.9{\pm}4.4$ and $2.6{\pm}7.8m$, respectively, in the deciduous broadleaf woodland of Hamyansangrim. The DEI on the maximum 10 minutes average MRT, UTCI from the three-dimensional environment absorbed by the human-biometeorological reference person during the daytime(10:00~17:00) were detected to be $7.1{\pm}1.7$ and $4.3{\pm}4.6m$, respectively, in the relatively sparse woodland of Hadongsongrim. These were detected to be $5.8{\pm}4.9$ and $3.5{\pm}4.1m$, respectively, in the dense and closed woodland of Hadongsongrim. Edge effects on the thermal environments of air temperature, relative humidity, wind speed, MRT and UTCI in the sparse woodland of Hadongsongrim were less pronounced than those recorded in densed and closed woodland of Hamyansangrim. The gradient variation was less steep for maximum 10 minutes average UTCI with at least $4.3{\pm}4.6m$(Hadongsongrim) and $3.5{\pm}4.1m$(Hamyansangrim) being required to stabilize the UTCI at mature woodlands. Therefore it is suggested that the woodlands buffer widths based on the UTCI values should be 3.5~7.6 m(Hamyansangrim) and 4.3~8.9(Hadongsongrim) m on each side of mature woodlands for users' thermal comfort environments. The woodland edge structure should be multi-layered canopies and closed edge for the buffer effect of woodland edge on woodland users' thermal comfort.

• Journal of the Korean Institute of Landscape Architecture
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• v.50 no.5
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• pp.80-89
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• 2022

In order to solve the limitations of horizontal thermal environment improvement, this study compared the thermal environment of the indoor and outdoor of a building in summer according to the presence or absence of a green curtain, a vertical greening method. In the summer of 2021, the air temperature, relative humidity, wind speed, and shortwave and longwave radiation were measured at a central point inside a building and the grass field outside of the building to determine the human thermal sensation index, PET and UTCI. As a result, the green curtain showed an average 1.6℃ cooler air temperature during the daytime, but it did not have an effect at night. For relative humidity, it showed higher humidity indoors by an average of 5.6% and 1.0% during the daytime and at night, respectively. Wind speed was 1.4-1.8 ms^-1 and 1.4-1.5 ms^-1 higher outdoors on average during the daytime and at night, respectively, showing a high value outdoors regardless of whether a green curtain was installed. The green curtain showed an average indoor mean radiant temperature reduction effect of 4.7℃ during the daytime, but it did not have an effect at night. In PET and UTCI, the green curtain reduced the indoor PET by about a 1/3 level, an average of 2.1℃, and the indoor UTCI by about a 1/6 level, an average of 1.1℃, during the daytime. However, no effects appeared in PET and UTCI at night. For landscape planning, a green curtain can effectively modify the thermal environment during the daytime in summer.

• Proceedings of the Korean Institute of Landscape Architecture Conference
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• 2020.10a
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• pp.48-49
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• 2020

• Journal of Environmental Science International
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• v.25 no.9
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• pp.1269-1281
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• 2016

This study evaporative cooling system a heat wave climate change and reduction of the inside and outside thermal environment change research. Measurement items included micro meteorological phenomena and measured comfort indices. A micro meteorograph of temperature, relative humidity, surface temperature, and the comfort indices of WBGT, UTCI, and PMV were measured. The difference in inside and outside temperatures were compared for different land types, with the largest difference found in Type A ($4.81^{\circ}C$), followed by Type B ($4.40^{\circ}C$) and Type C ($3.12^{\circ}C$). Relative humidity was about 10.43% higher inside due to water injection by the evaporative cooling system. Surface temperature was inside about $6.60^{\circ}C$ higher than the outside all types. WBGT were Type A ($3.50^{\circ}C$) > Type B ($2.71^{\circ}C$) > Type C ($1.88^{\circ}C$). UTCI was low heat stress inside than outside all types. PMV was analysed Type C for inside predicted percentage of dissatisfied 75%, other types was percentage of dissatisfied 100% by inside and outside. Correlation analysis between land cover type and temperature, surface temperature, pmv, utci. T-test analysed inside and outside temperature difference was significant in all types of land.