Sensitivity study of WRF and RegCM models to different physics schemes during two extreme weather events over Europe

Urban environments not only affect the warming rate over cities but also induce changes in other relevant meteorological variables. One of the main goals of the FPS URB-RCC Project and the Horizont research project Impetus4Change (I4C) is to improve our understanding of the impact of urban areas on the regional climate and vice versa, as well as to identify how urban parameterizations impact the regional-to-local scale processes, and, in general to improve the quality, accessibility and usability of near-term climate information. To evaluate these impacts in the long term, first we need to find the “best” configuration possible for our models and then validate them against high-quality observations.  

 

In this study, we present preliminary results from a series of sensitivity tests focusing on two extreme events occurred in 2020 over Paris, with the aim of finding the “best” model configuration. Simulations were performed using two models (WRF and RegCM5) with a double-nested domain at 12 and 3 km resolution, respectively, centered over Paris. Urban schemes of different complexity are used in WRF (in particular, we use the bulk, SLUCM and BEP+BEM urban schemes) as well as different physics options in both models. In the case of the RegCM5 model, different cores were tested too. The results show that relevant meteorological variables, such as temperature and precipitation, depend on the urban canopy scheme used as well as on the microphysics and planetary boundary layer schemes. Moreover, the effects of dynamical core in RegCM5 are more prominent than explicit moisture schemes for simulation of heat wave events.