[AAS15-05] Observational and numerical studies on thermal environment in high-density residential areas and urban renewal sites in Tokyo
Keywords:Summertime thermal environment, High-density residential areas, Urban renewal areas, In-situ measurements, Airborne remote sensing, CFD simulations
This study was performed as part of considerations of adaptation and mitigation measures that can improve micro-scale summertime thermal comfort in downtown Tokyo.
First, spatiotemporal changes in amounts of thermal infrared (TIR) energy emitted from urban surfaces in downtown Tokyo were analyzed using 2 m spatial resolution data obtained from airborne TIR measurements performed at midday on the four different hot summer days: Aug. 19, 2013, Aug. 19, 2014, and Aug. 19, 2015. Detailed land use data were also used to analyze the relationship between amounts of TIR energy and land use variations. The results showed significantly large amounts of TIR energy in high-density residential areas, although amounts of TIR energy in areas with office and commercial buildings including urban renewal sites were relatively small. This indicate that some governmental measures are required to improve thermal comfort in high-density residential areas. In downtown Tokyo, the maximum occurrence frequency of heat strokes tends to be recorded in residential areas and at midday.
Secondly, this study therefore investigated characteristics of thermal environment in some high-density residential areas located in Tokyo, using data from computational fluid dynamics (CFD) and in-situ meteorological measurements performed by smart weather sensors installed in about 30 single-family wooden detached houses in periods of July-Sep. in 2016, 2017, and 2018. The results indicate that 1) decreases of air temperatures and water vapor amounts in indoor spaces in the afternoon, 2) improvement of radiative environment on houses, and 3) increases of outdoor wind velocities would be effective measures for improvement of thermal environment in the high-density residential areas.
Thirdly, we have started a research project for investigating thermal comfort influenced by creation of green spaces in urban renewal sites. In this research project, we have performed in-situ measurements and airborne remote sensing in the period from Jul. 30 to Sep. 30, 2019 in the Kita-Aoyama San-chome renewal site prior to creation of green spaces in the renewal site. Numerical simulations using a CFD model have also been conducted. We will show results of the measurements and simulations in our presentation.
First, spatiotemporal changes in amounts of thermal infrared (TIR) energy emitted from urban surfaces in downtown Tokyo were analyzed using 2 m spatial resolution data obtained from airborne TIR measurements performed at midday on the four different hot summer days: Aug. 19, 2013, Aug. 19, 2014, and Aug. 19, 2015. Detailed land use data were also used to analyze the relationship between amounts of TIR energy and land use variations. The results showed significantly large amounts of TIR energy in high-density residential areas, although amounts of TIR energy in areas with office and commercial buildings including urban renewal sites were relatively small. This indicate that some governmental measures are required to improve thermal comfort in high-density residential areas. In downtown Tokyo, the maximum occurrence frequency of heat strokes tends to be recorded in residential areas and at midday.
Secondly, this study therefore investigated characteristics of thermal environment in some high-density residential areas located in Tokyo, using data from computational fluid dynamics (CFD) and in-situ meteorological measurements performed by smart weather sensors installed in about 30 single-family wooden detached houses in periods of July-Sep. in 2016, 2017, and 2018. The results indicate that 1) decreases of air temperatures and water vapor amounts in indoor spaces in the afternoon, 2) improvement of radiative environment on houses, and 3) increases of outdoor wind velocities would be effective measures for improvement of thermal environment in the high-density residential areas.
Thirdly, we have started a research project for investigating thermal comfort influenced by creation of green spaces in urban renewal sites. In this research project, we have performed in-situ measurements and airborne remote sensing in the period from Jul. 30 to Sep. 30, 2019 in the Kita-Aoyama San-chome renewal site prior to creation of green spaces in the renewal site. Numerical simulations using a CFD model have also been conducted. We will show results of the measurements and simulations in our presentation.