Climate Change Scenarios for Hungary Based on Numerical Simulations with a Dynamical Climate Model

Climate models are systems of partial differential equations based on the basic laws of physics, fluid motion, and chemistry. The use of high resolution model results are essential for the generation of national climate change scenarios. Therefore we have adapted the model PRECIS (Providing REgional Climates for Impacts Studies), which is a hydrostatic regional climate model HadRM3P developed at the UK Met Office, Hadley Centre, and nested in HadCM3 GCM. It uses 25 km horizontal resolution transposed to the Equator and 19 vertical levels with sigma coordinates. First, the validation of the model (with two different sets of boundary conditions for 1961-1990) is accomplished. Results of the different model experiments are compared to the monthly climatological data sets of the Climatic Research Unit (CRU) of the University of East Anglia as a reference. Significance of the seasonal bias fields is checked using Welch's t-test. Expected future changes - in mean values, distributions and extreme indices - are analysed for the period 2071-2100. The results suggest that the significant temperature increase expected in the Carpathian Basin may considerably exceed the global warming rate. The climate of this region is expected to become wetter in winter and drier in the other seasons.