EFFECTS OF CLIMATE CHANGES ON WATER AVAILABILITY IN CENTRAL EUROPE
J. MIKA, ILONA PAJTÓK-TARI, G. VARGA, G. BÁLINT
ABSTRACT. – Effects of projected climate changes both on average conditions and extremes are investigated by the use of global climate models of the IPCC AR4 (2007). Computed changes in 21 coupled ocean-atmosphere general circulation models (OAGCM) are first analysed for periods 2080-2099 and 1980-1999, focusing on hydrology related parameters, including precipitation, runoff, mean temperature, diurnal temperature range, cloud coverage and soil moisture. In a wide sub-set of the models, the decrease of runoff indicates lower amount of water energy. A few percent of decrease is projected in the soil moisture, as well. The precipitation and temperature results, including their inter-model variance and change of temporal variability projected by the same global models additionally are adjusted to the 2030-2049 time slices, selected for flood hazard assessment. The MAGICC/SCENGEN 5.3v2 diagnostic model (Wigley, 2008) is used to adjust the model results to the external forcing alternatives and time-horizons. The projections are based on the moderately rapid A1B emission scenario, and a mitigation-oriented scenario postulating climate stabilisation at the 450 ppm equivalent CO2-scenario. Spatial resolution of both OAGCM-based scenarios is 2.5 x 2.5 deg. which is enough to describe robust features of the water balance. The inter-model variability of the sea-level pressure changes indicates that even the embedded mezo-scale models, not used in the present study, are not fully sound tools for regional climate projections. The study is closing by the discussion of the strong inter-model differences in the pressure changes, providing the boundary conditions for the next, mezo-scale generation of the regional climate models.
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