Thermal assessments at local and micro scales during hot summer days: a case study of Belgrade (Serbia)

Abstract

Increasing thermal risk in cities is endangering the health and well-being of urban population and is driven by climate change and intensive urbanization. Therefore, if we plan to enlarge the capacities of cities to be more climate resilient in the 21st century, more detailed monitoring of urban climate on local and micro scales is needed. For this research we performed two microclimate measurement campaigns in urban area of Belgrade, during hot summer days in 2021. In total, five measurement sites were chosen in different urban designs and different local climate zones (LCZs). For thermal monitoring (air temperature – Ta and globe temperature – Tg) the Kestrel heat stress tracker sensor with 1-min measurement resolution was used, but we used 10-min average values. Obtained results showed distinct thermal differences (up to 7 °C on average) between densely built-up areas and green areas. Differences between built-up LCZs are lower with values from 2 to 4 °C. Important part of this research was microclimate monitoring on sites within the same LCZ (intra-LCZ variability). Results showed that shadows and short- and longwave radiation play a paramount role in thermal variability. Direct and reflected radiations on one measurement site increased Ta up to 6 °C and Tg up to 12 °C when compared to other measurement site (in a similar urban design), which was in the shadow.