• High-resolutiosn microclimate modelling for two urban study areas with ENVI-met • 54 scenarios were designed implementing technical- and nature-based solutions • Intercomparison of climate change adaptation potentials between India and Germany • Significant mean cooling effects of -1.6 K (India) and -2.9 K (Germany) were found • Technical solutions perform better in India, nature-based ones better in Germany Many cities around the world are affected by the urban heat island effect which is expected to intensify in the upcoming decades. The heat mitigation potentials vary largely between cities, depending on the overall climatic and hydrological conditions, urban geometry and structure, as well as societal and cultural differences. Thus, climate change adaptation measures to mitigate the increasing heat exposition of urban dwellers must be implemented specifically to the given local physical and societal conditions. This paper comparatively assesses the cooling potentials of different adaptation pathways for two urban areas with vastly different climate and societal conditions, namely the humid mid-latitude city of Cologne in Germany and the semiarid tropical city of Pune in India, by using the physically-based 3D-gridded high-resolution microclimate model ENVI-met. The model was parameterized based on field measurements and remote sensing data, and validated using quality-controlled, densely-distributed, participatory citizen science microclimate sensor networks within the two study areas. A mean Nash-Sutcliffe model efficiency coefficient of 0.9 and up to 0.98 for simulated air temperature indicates a high statistical goodness-of-fit of the model to measurements. 54 different climate change adaptation scenarios were investigated by implementing various technical- and nature-based solutions as well as combinations of these. While significant cooling effects for air temperature and physiological equivalent temperature of up to -1.6 K (-2.9 K) were identified for Cologne, cooling effects are smaller in Pune with up to -1.2 K (-1.6 K). For air temperature, technical solutions mostly perform better in Pune, while in Cologne, nature-based solutions usually show a better heat mitigation performance. This can be attributed to limited water availability in India during the hot pre-monsoon period. PET cooling effects are smaller in Pune for nearly all scenarios.
Eingrüber et al. (Sun,) studied this question.