Convection Permitting Regional Climate Modelling Over the Carpathian Region

Abstract A preliminary analysis of the performance of the latest version of the RegCM regional modelling system, RegCM5, run at a convection permitting resolution (2 km) over the Carpathian Basin is presented for the following years: 1980, 2006, 2008 and 2010. The performance of the model is assessed using various statistics of surface air temperature and precipitation against the CARPATCLIM high-resolution observational dataset and the ERA5 reanalysis, which also provides the driving field for the simulations. While the model performs generally well, it exhibits a warm bias over the Hungarian lowlands during the warm season and a wet (dry) bias over the mountain chains (flat regions) within the basin. The model also shows a strong orographic forcing of precipitation. In general, RegCM5 has a systematic positive precipitation bias over mountainous regions, which can also be attributed to the relatively low station density of the observation network. The high-resolution model adds value especially for simulating medium to high-intensity precipitation events. Our preliminary experiments provide encouraging indications towards the applicability of RegCM5 to the Carpathian region. Future work will include testing the model with different physics configurations and longer simulations and applying the model to climate change studies over the Carpathian Basin.