14:10 〜 14:30
[HCG22-02] An experimental study of the microclimate and thermal comfort of temple gardens in Kyoto, both in summer and winter.
★Invited Papers
キーワード：microclimate, thermal comfort, temple garden
This study was conducted aiming to understand meteorological conditions of Japanese temple gardens in Kyoto. The study site, Kyoto is not the hottest city in Japan, but ranks top for number of extremely hot days among the cities in Japan. The Geographical feature of Kyoto, being surrounded on three sides by mountains, contributes to its characteristic climate - highly humid climate. The high humidity does not only exacerbate people’s thermal comfort in summer, but also in winter, even though the average temperature in winter is relatively mild.
Temple gardens in Kyoto are important cultural property, therefore many researchers have studied and written about the history of Japanese gardens, gardening techniques, scenic and cultural value, and etc. However, very few is known regarding how the design of temple gardens developed in the context of the local climate. The popularity of temple gardens in Kyoto owes to the good experiences of people in gardens, including the comfortable thermal environment, such as a gentle breeze in summer and warm sunlight in winter. Hence, this study seeks to explore the hypothesis that temple gardens were developed in their long history, to adapt to and modify harsh local climate.
Three temple gardens, Shoren-in garden, Chion-in garden, and Joju-in garden were chosen as study gardens. The study sites were chosen carefully while considering their construction time, garden scale, location and characters. All of the three study gardens were located in the eastern side of Kyoto, were constructed in the Edo period and have a pond in the gardens. In the study gardens, observation points were mainly set at Engawa of halls where people come and have a seat and watch the gardens. At each observation point, thermometers were placed to measure meteorological data, such as air temperature, relative humidity, globe temperature and wind speed. Meteorological data collection was done for 3 days at each garden from 9am to 16pm, both in August 2017 and February 2018.
Thermal comfort of the gardens was evaluated by calculating PET (Physiological equivalent temperature) with the meteorological data collected at the study gardens. Spatial configuration of the gardens was analyzed by measuring garden elements such as canopy area, pond area, and etc. Finally, statistical analysis was carried on to test the relationship between the garden thermal environment and the garden design.
Results show that, thermal comfort of all the observation points were cooler and more comfortable than surrounding urban areas in summer, though to different degrees in different points. In winter, not all but most of the points are warmer and more comfortable compared to surrounding urban areas. Regarding the relationship between garden spatial configuration and thermal condition, we found that the interactions between the garden elements and garden microclimate change dramatically in a day. The interactions change with distance to study points, time of a day, area of garden elements, and season.
Firstly, study results indicate that ponds and pavement are the most outstanding influencers in summer. The ponds in the study gardens improve thermal comfort significantly during noon, but the cooling effects decrease greatly with the distance to the study points increases. Pavement, however, negatively affects thermal comfort in the morning and noon, regardless of the distance to the study points. There is no strong correlation between garden element area and thermal comfort is found in the morning and afternoon. Microclimate modification in winter was also mainly observed during noon. However, unlike the occasions in summer, more garden elements influence thermal comfort of the gardens and to a stronger degree. In winter, the larger areas of halls and pavement are related to higher thermal comfort. Oppositely, the area of ponds affects thermal comfort negatively.
Temple gardens in Kyoto are important cultural property, therefore many researchers have studied and written about the history of Japanese gardens, gardening techniques, scenic and cultural value, and etc. However, very few is known regarding how the design of temple gardens developed in the context of the local climate. The popularity of temple gardens in Kyoto owes to the good experiences of people in gardens, including the comfortable thermal environment, such as a gentle breeze in summer and warm sunlight in winter. Hence, this study seeks to explore the hypothesis that temple gardens were developed in their long history, to adapt to and modify harsh local climate.
Three temple gardens, Shoren-in garden, Chion-in garden, and Joju-in garden were chosen as study gardens. The study sites were chosen carefully while considering their construction time, garden scale, location and characters. All of the three study gardens were located in the eastern side of Kyoto, were constructed in the Edo period and have a pond in the gardens. In the study gardens, observation points were mainly set at Engawa of halls where people come and have a seat and watch the gardens. At each observation point, thermometers were placed to measure meteorological data, such as air temperature, relative humidity, globe temperature and wind speed. Meteorological data collection was done for 3 days at each garden from 9am to 16pm, both in August 2017 and February 2018.
Thermal comfort of the gardens was evaluated by calculating PET (Physiological equivalent temperature) with the meteorological data collected at the study gardens. Spatial configuration of the gardens was analyzed by measuring garden elements such as canopy area, pond area, and etc. Finally, statistical analysis was carried on to test the relationship between the garden thermal environment and the garden design.
Results show that, thermal comfort of all the observation points were cooler and more comfortable than surrounding urban areas in summer, though to different degrees in different points. In winter, not all but most of the points are warmer and more comfortable compared to surrounding urban areas. Regarding the relationship between garden spatial configuration and thermal condition, we found that the interactions between the garden elements and garden microclimate change dramatically in a day. The interactions change with distance to study points, time of a day, area of garden elements, and season.
Firstly, study results indicate that ponds and pavement are the most outstanding influencers in summer. The ponds in the study gardens improve thermal comfort significantly during noon, but the cooling effects decrease greatly with the distance to the study points increases. Pavement, however, negatively affects thermal comfort in the morning and noon, regardless of the distance to the study points. There is no strong correlation between garden element area and thermal comfort is found in the morning and afternoon. Microclimate modification in winter was also mainly observed during noon. However, unlike the occasions in summer, more garden elements influence thermal comfort of the gardens and to a stronger degree. In winter, the larger areas of halls and pavement are related to higher thermal comfort. Oppositely, the area of ponds affects thermal comfort negatively.