Urban microscale simulations based on a Local Climate Zone wizard: Concept and validation using the PALM model system

Local Climate Zones (LCZs) constitute a classification system for urban and rural sites, linking physical properties and urban morphology with characteristic near-surface temperature regimes. We developed a new python-based tool, called LCZ-wizard, that allows for creating and customizing physical surface characteristics of entire cities based on small units consistent with the LCZ definitions. Therewith, we are able to generate and facilitate microscale meteorological modeling of cities based on a LCZ classification only, providing an addition to traditional remote sensing-based mapping and in-situ measurement methods to study the urban microclimate. In this paper, we evaluate the performance of the building-resolving PALM model system under heatwave conditions, with surface properties provided by the LCZ-wizard. One simulation was performed for each standard LCZ, and results show that characteristic air temperature and human thermal comfort patterns were reproduced by PALM for each LCZ. Furthermore, we performed additional simulations for an existing city quarter in Berlin, Germany, one with realistic surface characteristics and two with semi-idealized LCZ surface information using the LCZ-wizard. The comparison reveals only small variations and differences (0.17 K and 0.34 K) in the diurnal cycle of air temperatures—when averaged over a typical LCZ-scale. Therewith we can verify the functionality and applicability of the LCZ-wizard for systematic investigations of urban environments in microscale simulations. We hence believe that the LCZ-wizard will be an valuable tool for urban climate research, e.g. by allowing high-fidelity microclimate simulations based on a LCZ mapping only, when detailed information on three-dimensional surface characteristics are absent.