16HEALTH Quantifying Thermal Health Hazards with High-Resolution

Thermal stress indices, like the Universal Thermal Climate Index (UTCI), play a crucial role in assessing thermal health hazards (both heat and cold-related). UTCI is the offset of air temperature, water vapour pressure, wind velocity, and Mean Radiant Temperature (MRT). MRT could be calculated from numerical weather prediction models using the cosine of the solar zenith angle (cossza) and radiation variables (longwave and shortwave, both upwards and downwards, as well as direct and diffuse components). This study aims to:
i) calculate MRT and UTCI with high-resolution (5.5 km x 5.5 km);
ii) compare methods settings for MRT calculation;
iii) contrast it with the established ERA5-HEAT dataset;
iv) validate the results against the Baseline Surface Radiation Network.
The study, based on the Copernicus European Regional ReAnalysis (CERRA) numerical weather prediction system radiation and meteorological outputs at the pan-European scale, has significant implications for diverse landscapes. The results show a previously neglected effect of cossza integration methods on MRT. However, when the direct radiation component is not available, MRT daily maximums are underestimated. High-resolution MRT and UTCI perform similarly to ERA5-HEAT for plains and show significant improvement for elevated and coastal areas. These findings underscore the relevance and applicability of robust thermal stress assessment across diverse landscapes, potentially revolutionising other thermal environment applications and indices like Physiological Equivalent Temperature or Wet Bulb Globe Temperature.