Climate Change Impacts On Extreme Precipitation In Greek Areas

Panagiota Galiatsatou, Sotiris Pagonopoulos, Panayotis Prinos

Tuesday 30 june 2015

11:30 - 11:45h at North America (level 0)

Themes: (T) Extreme events, natural variability and climate change, (ST) Hydrological extremes: floods and droughts

Parallel session: 5I. Extreme events - FloodDrought

In the present paper the effects of climate change on precipitation extremes in four selected Greek areas are analyzed and studied. The datasets used result from the regional climate model RegCM3 with a spatial resolution of 10 x 10 km and cover a time period of 150 years (1951-2100). The available precipitation data for each region is separated in three parts of equal size (fifty years each), in order to represent the fifty years of the current, the short-term and the long-term future climate. Model precipitation data are found to be biased, compared to precipitation observations available at the four sites, making it necessary to implement various methods of bias-correction. Both parametric and non-parametric methods are used for all four regions analysed, selecting the most appropriate for each case. Extreme value theory is then implemented to the bias-corrected precipitation datasets and both GEV (Generalized Extreme Value Distribution) and GPD (Generalized Pareto Distribution) are fitted. The parameters of these distributions are assessed and goodness of fit tests are performed. For the GPD distribution function, declustering of the excesses over the selected thresholds is used to insure independence. Return level estimates of each 50 years-period for both distributions are found and compared to assess the effects of climate change on precipitation extremes in each selected area.