Evaluation of different bias-corrected EURO-CORDEX databases and the expected future changes in precipitation over Hungary

The main goal of the present research is to investigate the projected changes of mean precipitation characteristics and to analyze precipitation-related climate indices over Hungary for two future time slices (2021-2050, 2070-2099) with respect to 1976-2005. In addition, our aim is to investigate how the choice of the reference dataset and different calibration periods affects the projected changes. For this purpose, results of different datasets were compared, including raw and bias-corrected EURO-CORDEX regional climate model (RCM) simulations. Namely, three bias-corrected databases were examined: RCM projections from the EURO-CORDEX initiative using MESAN as reference data, the FORESEE-HUN database, and a bias-corrected dataset newly created for this research with the use of the quality-controlled, measurement-based HuClim dataset. Each database contains the same 5 RCMs on a horizontal resolution of 0.11° following the RCP4.5 and RCP8.5 Representative Concentration Pathway scenarios. Firstly, the evaluation of the different sets of RCM simulations was carried out for the 2006-2022 period. For the future, under the RCP4.5 scenario, the change in mean annual precipitation remains below 20 % in both future time slices, and only minimal differences were found between the databases. Under RCP8.5 the expected changes are more robust, the greatest increase is projected in the mountainous areas. In the Northern Mountains, the HuClim-based bias-corrected simulations show the most pronounced (26-30 %) increase, while the raw and bias-corrected RCM simulations using MESAN indicate the smallest changes. Winter precipitation is likely to increase according to all databases under both scenarios by up to 52 %.