Thermal performance of the Urban Weather Generator model as a tool for planning sustainable urban development

Abstract

The research aims at assessing the sensitivity of the Urban Weather Generator v4.1 to the application of different mitigation strategies for the urban heat island under two climatic contexts: desert climate (Mendoza city) and tropical climate (Campinas city). Twenty-four scenarios that modify their morphologic and material parameters were simulated. The results showed that the temperature of the air predicted by the UWG model is not significantly sensitive to the changes produced by the application of different strategies in urban contexts of equal H/W aspect; however, it does show sensitivity to the variation of the H/W aspect (ΔTa ≤ 1.3°C) and the climate context. The highest performance of the UWG model was recorded on the surface temperatures of the urban envelope, with a maximum difference in surface temperature was recorded on high aspect ratio with high albedo in arid climate, (Ts of roof = 28°C).

Evaluation of the Urban Weather Generator on the City of Toulouse (France)

“…When looking into details, we observe that the models tend to overestimate at night and underestimate during daytime, as particularly remarkable in Figure 11. This is in accordance with conclusions from [32,33] where in general, an overestimation of urban temperature in summer was detected.…”

“…Among existing models, Urban Weather Generator (UWG) [28] is an appealing compromise since it is open source, easy to operate, and applicable at a city scale. To our knowledge, this model has been evaluated on nine cities: Toulouse (France) and Basel (Switzerland) [29], Singapore [30], Boston (USA) [31], Rome (Italy) and Barcelona (Spain) [32], Mendoza (Argentina) and Campinas (Brazil) [33], and Abu Dhabi (United Arab Emirates) [34], with slightly different versions since UWG is still under development and continuously updated [35]. The main conclusions made in these papers are (i) that UWG performances are satisfactory with an RMSE of about 1 °C and (ii) that UWG overestimates urban air temperatures during daytime in winter and underestimates nighttime air temperatures in summer.…”