ENVI-Met 시뮬레이션을 통한 도로 방향별 가로수 식재 형태에 따른 여름철 열환경 개선 효과 분석

Abstract

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 (<italic>T_mrt</italic>) 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 <italic>T_mrt</italic>, and PET and UTCI showed similar patterns with <italic>T_mrt·</italic>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). <italic>T_mrt</italic>, 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°C PET and 4.2-4.5°C UTCI at 10:00, and the northeast, east and southeast sidewalks showed 8.1-11.8°C PET and 4.4-5.0°C 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°C PET and 0.9°C UTCI on the eastern sidewalks, and up to 3.0°C PET and 0.9°C UTCI on the western ones. In addition, the difference in modification effects on <italic>T_mrt</italic>, 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.