A Contribution to Microclimatic Zone Classification (MCZ)

The challenge of transferring scientific knowledge on urban climate to urban planning and design practices is persistent. Even though the Local Climate Zone (LCZ) classification tries to provide useful information to urban planning and design communities, it is more focused on a scale at which design decisions are seldom made. Approaches helpful to architects, landscape architects and urban designers need a finer spatial scale classification. This led to the exploration of Microclimatic Zone Classification (MCZ), derived based on urban parameters such as building façade materials, surface materials and trees surrounding a person. This research aims to establish a nuanced empirical relationship between the human-scale urban parameters, street orientation, sky view factor, etc, and objective thermal comfort variables, such as Air Temperature (AT), Relative Humidity (RH), Mean Radiant Temperature (MRT) and Wind Speed (WS). The approach is demonstrated in a test case in Glasgow, Scotland, using a portable non-motorised weather station (developed for this research), on a ‘Stop-and-Go’ method to measure the above variables at 38 locations in Central Glasgow’s residential and commercial neighbourhoods. These 38 locations represent the full range of available combinations of human-scale urban parameters within the case study area, making each one uniquely distinct, and the observations were carried out for a year to capture the seasonal dynamics classified per atmospheric stability class for the observation days. A regression technique using a Machine learning algorithm and the SHAP (SHapley Additive exPlanations) analysis was performed to understand the influence of various human-scale urban parameters on the objective thermal comfort variables, especially MRT (calculated using AT, WS and globe temperature). Overall, this research helps to understand the influence of urban parameters surrounding a person by ranking them from the least to the most influential in terms of their impact on thermal comfort.