Temporal evolution of extreme weather in Romania (1940-2024)

Romania is a country situated in Southeast Europe, and due to its geographical position, it is exposed to different climatic hazards (heatwaves, floods, droughts). In the context of climate change, extreme weather phenomena are becoming increasingly frequent and intense, including in Romania. Compound events (CEs) are a combination of different hazards/climate drivers that can pose a significant risk to society and the environment. One type of CEs is multivariate events, when multiple hazards/climate drivers are co-occurring in the same geographical region. In this study, we analyzed multivariate events in Romania from 1940 to 2024 using CETD (Compound Events Toolbox and Dataset). This tool can generate the duration, frequency, and severity of compound events. Daily maximum temperature (tasmax), daily minimum temperature (tasmin), total precipitation (pr), mean surface wind speed (sfcWind), and mean wind speed at 500 hPa (preWind500) were extracted from ERA5 reanalysis dataset obtained from the Copernicus Climate Change Service (C3S) Climate Data Store (CDS), with a spatial resolution of 0.25°x0.25°. We selected three hazard pairs related to extreme hot temperature: hot-dry, hot-stagnation, and hotday-hot night. Each hazard was defined as follows: hot (tasmax ≥95th percentile), dry (pr<5th percentile), windy (sfcWind ≥ 95th percentile), and stagnation (sfcWind<3.2 m/s and preWind500 < 13 m/s). The results indicate that specific areas in Romania are vulnerable to these three compound events, with a significant trend over recent decades, pointing to the need for effective risk mitigation implementation.

 

This study was carried out within Nucleu Program, contract number 24N/03.01.2023 (SOL4RISC), project no. PN23360202 and Catalina – Roxana Bratu’s PhD project at the Faculty of Physics, University of Bucharest.  Contact: Drd. Catalina-Roxana BRATU, catalina.bratu@infp.ro. This work was supported by a grant of the Ministry of Education and Research, CCCDI - UEFISCDI, project number PN-IV-P6-6.1-CoEx-2024-0042, within PNCDI IV.