How does a model capture human thermal sensation?

Abstrakt

ZÁKLADNÍ ÚDAJE: PMC26 Book of Abstracts. Hannover: Leibniz University Hannover, German Weather Service, 2026. s. 27-28. [PMC 26: PALM Model Conference. 23.02.2026-26.02.2026, Hannover]. ABSTRAKT: Urban heat exposure threatens billions worldwide, yet effective mitigation remains challenging—cities struggle to pinpoint intervention priorities at the pedestrian scale where thermal stress is most acutely experienced. Traditional urban climate research focuses on measuring or modelling the physical thermal environment, yet how people cope with and perceive heat is far more complex. Beyond thermal exposure as the primary environmental component, human thermal experience is shaped by psychological and behavioural factors largely overlooked in current approaches. While high-resolution models like PALM can precisely simulate thermal exposure at microscales, comparison to actual human thermal perception remains limited. We address this gap by integrating PALM simulations with a citizen science thermal walk campaign, collecting 3,666 georeferenced real-time thermal sensation reports on a hot summer day across the Prague-Holešovice district. This integrated approach revealed substantial microscale thermal heterogeneity that was invisible to conventional measurements, with statistical analyses confirming that mean radiant temperature (MRT) was the dominant predictor of thermal sensation. The northern sides of east-west-oriented streets without trees emerged as systematic thermal hotspots, whereas mature street trees provided relief comparable to building shade, reducing reported severe discomfort by more than half. Open impervious surfaces amplified heat stress to levels matching the worst street conditions, yet accessible vegetated spaces just dozens of metres away provided substantial thermal refuges. This approach demonstrates that effective heat adaptation requires microscale interventions targeting radiation exposure.