Projection of Compound Events for Central/Eastern Europe

Regional climate models project a clear temperature increase as well as substantial changes in the annual distribution of precipitation for the Carpathian Basin (located in Central/Eastern Europe. The change of either of these climatic elements alone can result in negative effects on many sectors, e.g., agriculture, water management, human health, etc. However, if the simultaneous inter-linked changes of temperature and precipitation are considered, the overall impact can be even more severe. Therefore, we focus on the analysis of compound events in the Carpathian region based on observed and modelled climate data with multivariate statistics, including probability distribution functions, and the analysis of return time of compound events based on their observed occurrences. For this purpose, gridded data with a horizontal resolution of 10 km are used: (i) the CarpatClim database that contains daily values of several meteorological parameters for the past (1961-2010), and (ii) regional climate model simulation outputs (1981-2100) produced by our experiments of the RegCM model. Regional climate model RegCM originally stems from the U.S. National Center for Atmospheric Research/Pennsylvania State University Mesoscale Model version MM4, and it is a 3-dimensional limited-area model maintained at the International Centre for Theoretical Physics (located in Trieste, Italy). The initial and lateral boundary conditions of our RegCM runs are from global climate models (i.e., HadGEM2 and MPI-ESM-MR). This study validates the past occurrence frequency of compound events in the reference period, and analyzes the projected changes in the intensity and frequency of compound events in the Carpathian region during the 21st century. Our results can serve as an important basis and key input for detailed subregional scale analysis and specific impact studies as well as for developing national climate and adaptation strategies.