4:00 PM - 4:15 PM
[HTT14-09] Microclimate simulation of Doshisha University Kyotanabe campus with ENVI-met model
★Invited Papers
Keywords:Microclimate, Urban environment, Numerical simulation
Microclimate refers to small-scale meteorology, ranging from a few meters to a few kilometers, and directly affects our daily activities. The microclimate formed in a certain place is strongly influenced by the surrounding environment, such as topography, land-use, and type of vegetation, which are provided within standard GIS datasets. Recently, the microclimate simulations have been performed with the boundary conditions generated from GIS datasets to get the information on local climate, such as daily maximum/minimum temperature, humidity, and wind speed. One of the microclimate models used in the world is ENVI-met, which calculates mass, momentum, and energy budgets in a 3-dimensional space through the Eulerian approach, developed by Michael Bruse (Bruse 1999; see www.envi-met.com). Many researchers have studied the simulation capabilities of ENVI-met (e.g., Crank et al., 2018; Lopez-Cabeza et al., 2018), and compared ENVI-met with other models (e.g., Paas and Schneider, 2016; Liu et al., 2020; Gal and Kantor, 2020). It has been found that the ENVI-met simulations are relatively precise, while there are situations where it cannot highlight the difference of solar radiation in space and time (Liu et al., 2020; Gal and Kantor, 2020). This research focuses on the verification of the numerical stability of ENVI-met model through the microclimate simulation of Doshisha University Kyotanabe campus, and explores the capability of ENVI-met to produce the useful information on the local climate and the impact of different environment layout on the microclimate.
Microclimate simulations of Kyotanabe campus for a period from 0:00 to 24:00 on December 1, 2020 are conducted with ENVI-met model. The simulation area is 300 m×170 m×73.29 m, and grid number 300×170×28. The locations and heights of buildings come from KML data generated by Google Earth. The vegetation types are selected from the ENVI-met database, according to the actual vegetation. The soil moisture and temperature are based on the observations by Kyoto-city (2018) and Kinouchi and Yoshitani (2001). Meteorological conditions for the simulations, including surface air temperature, wind speed, and wind direction, are provided by the observations at Kyotanabe AMeDAS of Japan Meteorological Agency. We compare the meteorological observations on the lawn in Kyotanabe campus with the ENVI-met simulations, and explore the relationship between the simulated microclimate and the surrounding environment.
Simulated surface air temperature shows the daily variations similar to those of the observed temperature, although the simulated temperature is about 2 degrees lower than the observed temperature in the daytime. This may be due to the setting of excessive cloud cover, resulting in less solar radiation. Simulated relative humidity is lower than the observed relative humidity in the nighttime, and opposite in the daytime. Simulated wind speed fluctuates little and is much larger than the observed wind speed. The deviation may be caused by inappropriate model settings. The simulated air temperature and wind speed show the dependence on the degree of closed environment by buildings and trees. The enclosure degree affects the flow of air and the amount of received solar radiation and lost heat. It is found that the closed environment has better heat conservation capability. The ENVI-met is basically good at microclimate simulations, and shows a significant impact of different environments on the microclimate. The enclosure degree of environment has a negative correlation with wind speed and relative humidity, and a positive correlation with air temperature.
Microclimate simulations of Kyotanabe campus for a period from 0:00 to 24:00 on December 1, 2020 are conducted with ENVI-met model. The simulation area is 300 m×170 m×73.29 m, and grid number 300×170×28. The locations and heights of buildings come from KML data generated by Google Earth. The vegetation types are selected from the ENVI-met database, according to the actual vegetation. The soil moisture and temperature are based on the observations by Kyoto-city (2018) and Kinouchi and Yoshitani (2001). Meteorological conditions for the simulations, including surface air temperature, wind speed, and wind direction, are provided by the observations at Kyotanabe AMeDAS of Japan Meteorological Agency. We compare the meteorological observations on the lawn in Kyotanabe campus with the ENVI-met simulations, and explore the relationship between the simulated microclimate and the surrounding environment.
Simulated surface air temperature shows the daily variations similar to those of the observed temperature, although the simulated temperature is about 2 degrees lower than the observed temperature in the daytime. This may be due to the setting of excessive cloud cover, resulting in less solar radiation. Simulated relative humidity is lower than the observed relative humidity in the nighttime, and opposite in the daytime. Simulated wind speed fluctuates little and is much larger than the observed wind speed. The deviation may be caused by inappropriate model settings. The simulated air temperature and wind speed show the dependence on the degree of closed environment by buildings and trees. The enclosure degree affects the flow of air and the amount of received solar radiation and lost heat. It is found that the closed environment has better heat conservation capability. The ENVI-met is basically good at microclimate simulations, and shows a significant impact of different environments on the microclimate. The enclosure degree of environment has a negative correlation with wind speed and relative humidity, and a positive correlation with air temperature.