Application of Low-Cost Sensors for Urban Heat Island Assessment: A Case Study in Taiwan

In the urban environment, the urban heat island effect, the phenomenon of high temperature in the city relative to the suburbs, has become significant due to a large amount of artificial heat dissipation, rare green spaces, high building density, and a large surface material heat capacity. The study of the urban heat island effect has been carried out for many years. Even though many studies have evolved from the measurement and analysis stage to the improvement of the urban heat island effect, the measurement method is still the most important issue of the studies in this field. Basically, the measurement method of the urban heat island effect intensity has three types: remote sensing, mobile transect observation, and fixed station. In order to achieve the dual purpose of reducing research funding requirements and maintaining the accuracy of research results, this study proposes a way to combine mobile transect observation and fixed station. This study exploits the advantages of mobile transect observation and fixed station, and uses low-cost sensors to achieve the basic purpose of urban heat island effect research. First, in this study, low-cost sensors were mounted on mobile vehicles for more than ten mobile transect observations to identify relatively high temperature and low temperature regions in the city; meanwhile, the low-cost sensors were also placed in a simple fixed station to obtain long-term instantaneous urban temperature data. Furthermore, it is possible to analyze the 24-hour full-time variation of the urban heat island effect. Therefore, the results of this study can not only provide a reference for relevant researchers, but can also serve as an important criterion for government departments to establish an urban heat island effect monitoring system to achieve the goal of efficient use of the public budget.