Improving Outdoor Thermal Comfort in a Steppe Climate: Effect of Water and Trees in an Urban Park

Abstract

Excess heat in urban environments is an increasing threat to human health and well-being. Furthermore, the increasingly important phenomenon of the Urban Heat Island (UHI) is exacerbating problems of livability in urban centers. Hence, there should be an increasing effort to assess the impact of heat mitigation strategies (HMSs) on outdoor thermal comfort in cities. This research has investigated how urban areas in steppe climate zones can be more thermally comfortable due to the effects of water bodies and trees, and how this might help to mitigate heat waves. Numerical simulations using the ENVI-met microclimate model have been performed for an urban park in Tabriz, Iran. In-situ measurements of air temperature (Ta) and mean radiant temperature (MRT) have been carried out in the study site and the collected data was used to validate the model (RMSE value 0.98 °C for Ta and 5.85 °C for MRT). Results show that water body evaporation without trees may decrease the air temperature, but on the other hand also increases the humidity, which reduces the positive impact on thermal comfort. However, the combination of water body with trees represents a better performance in the regulation of urban microclimate and thermal comfort.

Nature-Based Solutions for Cooling in High-Density Neighbourhoods in Shenzhen: A Case Study of Baishizhou

“…To reduce the influence of boundaries, the Z-axis height within the simulation range was set to be more than twice as high as the top-height building within the simulation range [43]. Consequently, 44 grids were set along the Z-axis.…”

“…To ensure data ity, the simulation period was set from 01:00 a.m. to 24:00 p.m. on the case stud for a duration of 24 h. Based on the actual site size, the X, Y, and Z axes of the m were set at 85, 85, and 44 grids with a two-meter resolution, respectively. A mes of 2 × 2 × 2 was set to provide a sufficient resolution for the analysis within a re able timeframe, given the computing resources and the required level of detai To reduce the influence of boundaries, the Z-axis height within the simulation was set to be more than twice as high as the top-height building within the simu range [43]. Consequently, 44 grids were set along the Z-axis.…”

“…To ensure data stability, the simulation period was set from 01:00 a.m. to 24:00 p.m. on the case study day, for a duration of 24 h. Based on the actual site size, the X, Y, and Z axes of the model were set at 85, 85, and 44 grids with a two-meter resolution, respectively. A mesh size of 2 × 2 × 2 was set to provide a sufficient resolution for the analysis within a reasonable timeframe, given the computing resources and the required level of detail [43]. To reduce the influence of boundaries, the Z-axis height within the simulation range was set to be more than twice as high as the top-height building within the simulation range [43].…”

“…A mesh size of 2 × 2 × 2 was set to provide a sufficient resolution for the analysis within a reasonable timeframe, given the computing resources and the required level of detail [43]. To reduce the influence of boundaries, the Z-axis height within the simulation range was set to be more than twice as high as the top-height building within the simulation range [43]. Consequently, 44 grids were set along the Z-axis.…”

Comparative Analysis of Urban Greening Design Scenarios on Microclimate and Thermal Comfort

“…Therefore, tree crown trans ection should be primarily towards sky on the sunlit side of trees. In addition, the quanti cation of tree shading bene ts, in terms of PET, provides an accurate measure of the real cooling effects for thermal comfort (De Abreu-Harbich et al, 2015;Teshnehdel, Gatto, Li, & Brown, 2022). The shape and size of trees can modify the effect in different climate regions (Shashua-Bar, Potchter, Bitan, Boltansky, & Yaakov, 2010).…”