Vertical variability of thermal comfort in urban areas: The example of Taipei 101
Chen, Yung-Chang; Lin, Po-Hsiung; Matzarakis, Andreas
In this study, we investigate urban biometerogical conditions on the basis of two stations at different levels (150 m and 350 m above screen level) at the skyscraper Taipei 101 (Taipei, Taiwan) and a long-term ground station at the National Taiwan University (NTU). The study addresses the vertical gradients of urban bioclimatic conditions in 2011. Physiologically Equivalent Temperature (PET) varied from ?0.6 °C to 48.9 °C depending on altitudinal and seasonal changes in Taipei. A PET comparison between the ground station and the height of 150 m shows that there were similar thermal conditions at the two layers during summer. However, PET was much lower at the height of 150 m than at ground station during winter. We conducted a thermal classification of PET on a Taiwanese thermal sensation scale. At the ground station, the occurrence of hot-day conditions was found to constitute approximately 35% of the hourly data during summer. Occurrence of hot-day conditions declined by 5% to 10% from the ground station, to the higher measurement levels of 150 m and 350 m, because of the decreasing air temperature. The probability of cold days between the ground station and the height of 350 m increased by 5% to 10% during winter, while there was a chance of approximately 90% that cold days would occur at the ground station.