Projected mean and extreme temperatures over Hungary: a multi-dataset assessment using bias-corrected EURO-CORDEX simulations

The most characteristic feature of contemporary climate change is the increase of global mean temperature on Earth. The latest report of IPCC points out that weather and climate events associated with extremely high temperatures are expected to become more frequent and more severe in the future compared to present conditions. One of the greatest threats to humans is heat waves , which pose serious health risks and are a major challenge for agriculture and energy production sector, too. On the other hand, not only records of extremely high maximum, but extremely high minimum temperatures occur more often, such as tropical nights. In order to build appropriate mitigation and adaptation strategies at global and regional levels, it is essential to analyse how the temperature is likely to change in the future.

The aim of our research is to investigate the projected changes of mean annual temperature over Hungary during the 21st century with a special focus on exceeding specific temperature thresholds (e.g. 1.5 °C or 2 °C) according to regional climate model simulations and how the frequency of temperature extremes will change under such conditions. The study also focuses on how the choice of the reference dataset and the calibration period affects the changes. For this purpose, the results of raw and bias-corrected EURO-CORDEX simulations are compared. In total, three sets of bias-corrected projections are included in the present study: publicly available EURO-CORDEX simulations using the MESAN database for the bias-correction, the FORESEE-HUN database and a newly created bias-corrected database, using the quality-controlled, measurement-based HuClim dataset  as a reference for the region of Hungary. Each database consists of the simulations of 5 RCMs (CCLM, HIRHAM, RACMO, RCA, REMO) from the EURO-CORDEX initiative at a horizontal resolution of 0.11°. The results of two Representative Concentration Pathway (RCP) scenarios are compared: the intermediate RCP4.5 and the business-as-usual RCP8.5.