The Role of Blue and Green Infrastructure in Thermal Sensation in Public Urban Areas: A Case Study of Summer Days in four Czech Cities

Abstract

Thermal comfort in public spaces, as an important factor in the quality of life, has been strongly affected by manifestations of climate change. City authorities are under pressure to adapt their approaches to the urban environment. This study investigates thermal sensation in public spaces in four Czech cities. Biometeorological measurements were taken and biometeorological indices (UTCI, PET, HUMIDEX) established, then contrasted with questionnaire surveys (thermal sensation vote – TSV). Regression models were subsequently constructed to explore the influences of elements of blue and green infrastructure beyond their microclimatic functions. The results suggest a highly complex relationship between biometeorological indices and TSV in urban environments, significantly influenced by specificity of place and time. Open grassy areas exhibit a lower probability of higher TSV related to heat stress. Despite measured microclimatic effects that might indicate the opposite, the probability of TSV-related heat stress is higher under trees and near sprayed water-mist. The findings herein thus indicate that simple predicted mean vote models are of little or no use in urban planning, and that sensitive and sustainable planning of heat mitigation measures should reflect the behavioural patterns of citizens alongside the microclimatic effects in actual place.