Exploring the Effect of Aspect Ratio (H/W) on Thermal Environment in Multiple Climate Zones with Open-Source Data

Abstract

For a country with multiple climate zones, analyzing the impacts of urban design in different climate zones is a prerequisite to climate adaptation policies. However, countries advanced in climate adaptation strategies are mostly located in a single climate zone, leading to a lack of research on climate adaptation policies for multiple climate countries. As China is launching the urban zoning management policy, this research takes China as an example to explore a technique to quickly distinguish the impact of urban design in multiple climate zones by combing the open-source data with the Envi-met tool, where the open-source data indicate the data that can be obtained from public platforms such as the internet and Envi-met is a microclimate simulation tool. First, the open street map tool, one of the open-source data, was used to abstract the typical models of each climate city. Then, open-source meteorological data were employed as the boundary conditions for Envi-met simulation. Lastly, after the Envi-met simulation, the impacts of aspect ratio (H/W) on multiple climate indicators in seven climate cities were analyzed with the meteorological interpolation method. The analytical results show that H/W has a stronger ability to regulate the thermal comfort of high latitude cities. In Guangzhou and Changsha, the maximum differences of PET caused by H/W are only 0.61 °C (Changsha) and 0.63 °C (Guangzhou). H/W has the strongest regulating effect on the thermal comfort in Harbin, with the highest value of 8.62 °C. The regulating effects of H/W on outdoor PET in other 4 cities are 4.37 °C in Urumqi, 3.29 °C in Xining, 1.29 °C in Xi’an, and 0.76 °C in Kunming. In addition, H/W mainly affects PET by modifying the radiant temperature. Compared with mean radiant temperature, the effects of H/W on air temperature, relative humidity, and wind speed are negligible. Longitude regulates the occurrence time of the coldest and hottest thermal environments. Among the seven climate zones in China, the difference in appearance time between the coldest and hottest reaches up to 2 h. For the implementation of urban zoning management policy, in China, high latitude cities are encouraged to high H/W to create a comfortable city. Cities whose latitude is less than 30° may not consider the impacts of H/W on thermal comfort. This method of combining open-source data with Envi-met can serve as a reference for other countries that span multiple climate zones. In addition, these results provide a decision-making basis for the management of H/W in different climate cities of China.