Convection permitting regional climate modelling with RegCM5 over the Carpathian Region

This study presents a preliminary analysis of the performance of the latest version of the RegCM regional modelling system, RegCM5, when run at a convection permitting resolution of 2 km over the Carpathian Basin. The performance of the model is evaluated by comparing various statistics of surface air temperature and precipitation against the CARPATCLIM high-resolution observational dataset and the ERA5 reanalysis, which is also utilized as the driving field for the simulations. Overall, the model performs well; however, certain biases are observed. During the warm season (JJA), a warm bias is detected over the Hungarian lowlands, while a wet (dry) bias is observed over the mountain chains (flat regions) within the basin. In addition, the model shows a significant orographic forcing effect on precipitation. An important finding is that the high-resolution of the model notably improves its ability to simulate medium to high-intensity precipitation events. This added value enhances its applicability, especially for the studies of such events. Given these promising initial results, future work will include further testing of the model with different physics configurations, longer simulations, and exploring its usability in climate change studies related to the Carpathian Basin.