What is the outdoor thermal comfort (OTC) threshold in Gulangyu, China: An empirical study

Empirical outdoor thermal comfort (OTC) research combining subjective questionnaires and objective measurements is emerging in different climate classifications around the globe, with the increasing climate change. The empirical OTC research in heritage destinations has become an indispensable basic work due to the demand difference with urban residential space and the constraints of the OTC measurement scale. Taking Gulangyu, a world heritage destination, as a case study, this paper establishes an OTC benchmark research framework (OTC-BERK-GLY) based on references to previous empirical research and outdoor thermal benchmarks, and reveals a multitude of OTC thresholds for different groups of people through the mathematical-statistical analyses of questionnaire data and Universal Thermal Climatic Index (UTCI). The results show: for foreign tourists, local tourists and islanders, 1) the maximum acceptable temperatures were 29.4 °C, 29.4 °C and 30.2 °C of UTCI, respectively, 2) the neutral temperature ranges were 14.0–25.6 °C, 14.1–26.8 °C and 15.1–28.3 °C, respectively, and 3) the preferred temperatures were 22.6 °C, 22.4 °C and 21.0 °C, respectively. This study also analyzed the main influences on OTC in Gulangyu using Discrete Choice Modeling (DCM), which shows that the physical environment was the main influence affecting the thermal sensation (TSV) of the respondents. And wind environment (va), sky view factor (SVF), age, time of exposure, group errands, and the use of parasols and sun-protective clothing had different levels of influence on thermal comfort (TCV). This study is intended to provide support for the development of climate adaptive tourism management in Gulangyu, and to provide a case study for similar heritage destinations.