A daily time-step hydrological-energy-biomass model to estimate green roof performances across Europe to support planning and policies

Nature-based solutions (NBSs) and urban greening are well-established strategies used in various planning and policy instruments to promote the sustainability of cities and mitigate the effects of climate changes. Within this context, green roofs are emerging as an effective NBS in urban areas where space is often limited. The estimation of green roofs' benefits is essential for their effective implementation and engineering design. In this contribution, we present a daily time-step model to estimate the surface temperature, the growth of vegetation cover and the hydrological behaviour of a green roof. The model is tested using twenty time series of real and independent European green roofs. Results show that, in the absence of calibration, the model can reproduce the daily surface temperature with high accuracy. The vegetation growing period is also reproduced. The hydrological variables can be estimated with moderate accuracy, and higher accuracy can be achieved when the model is calibrated. Therefore, the model proves a useful tool to support the appraisal of green roofs and the planning of green infrastructures in European cities.