On-site measurement and numerical simulation study on characteristic of urban heat island in a multi-block region in Beijing, China

Abstract

The urban heat island (UHI) effect can lead to an increase in winter temperatures in cold regions, which in turn increases energy consumption and air pollution within urban areas. Field measurements of UHI effects can provide high-precision and high-resolution data, making them suitable for investigating the spatial-temporal distribution of UHI. However, there have been relatively few studies on the field testing of UHI effects in multiple blocks, especially those that involve continuous monitoring. Additionally, while many studies have demonstrated the impact factors of UHI intensity, there is a scarcity of research on quantitative and weight analyses of these factors. In this study, on-site measurements of UHI characteristics were carried out in a typical multi-block region in Beijing. The on-site sampling was conducted in both summer and winter seasons for 29 consecutive sampling days with 20 sampling points. The average urban heat island intensity (UHII) during the sampling period was 1.7 ± 1.2 °C in summer and 3.7 ± 1.8 °C in winter. Temperatures measured at different sampling locations varied significantly, with a maximum spatial difference of 7.5 °C in summer and 4.1 °C in winter. Simulation results showed that, in summer, each ±10% change in wind speed, albedo, or solar radiation intensity would cause the UHII to change by ∓0.16 °C, ∓0.21 °C, or ± 0.17 °C, respectively. In winter, the effects of these factors were very limited. The effect weights of wind speed, albedo, and solar radiation intensity on UHII in summer were 31.3%, 36.6%, and 32.1%, respectively. The position of green space in relation to the dominant wind direction of the city would have a greater effect on UHI mitigation in summer than in winter. This study provides a theoretical basis for mitigating UHI effects and is of great significance for sustainable urban design.