A Low-Cost Assessment Framework for Municipal Climate Adaptation: Combining UAV Thermography, Ground Monitoring, and Microscale Modeling in Aalen, Germany

Small- and mid-sized municipalities increasingly need to assess the long-term effectiveness of urban greening projects under climate change, but typically lack the resources for extensive measurement campaigns or complex simulation infrastructure. We propose and demonstrate a practical three-component assessment framework that can be deployed with limited resources: one or two UAV thermal surveys to capture the spatial baseline, a small network of fixed monitoring stations for temporal context, and a single microscale model to project future scenarios. We apply this framework to a 0.5 ha parking-to-park conversion in Aalen, Germany (pop. 68,000). A diurnal drone survey (four flights over 14 h) established surface temperature contrasts of up to 34 K between sealed and tree-shaded areas. Six fixed stations operating over six weeks confirmed that an existing mature linden reduced hot days by nearly 50%. The ASMUS_green microscale model, evaluated against the drone observations (mean absolute difference 3.4 K across surface types), was then used to project Physiologically Equivalent Temperature (PET) under EURO-CORDEX scenarios for 2035 (+1.3 K) and 2055 (+2.5 K) combined with tree growth. The results show that young trees provide limited near-term relief, but mature canopy reduces PET by 6–8 K, offsetting the projected warming. We discuss how each component compensates for the limitations of the others, making the combined framework more robust than any single method. The approach is designed to be transferable to other municipalities facing similar planning decisions with comparable resource constraints.