EXTREME EVENTS AS REPRESENTED BY HIGH RESOLUTION CMCC CLIMATE MODELS AT GLOBAL AND REGIONAL (Euro-Mediterranean) SCALE

Abstract

One of the conclusions of the IPCC Fourth Assessment Report is that there are evidences that climate change affects the frequency, intensity, and length of many extreme events, such as floods, droughts, storms and extreme temperatures. At the same time, gradual and non-linear changes in ecosystems and natural resources further increase the consequences of extreme weather events. Climate extreme events are hard to study and even harder to predict because they are, by definition, rare and obey different statistical laws than averages. The availability of climate simulations (historical + sresA1B scenario) covering the period 1970-2100 from a global Coupled General Circulation Model (70 Km of atmospheric spatial resolution) and a Regional Climate Model (14 Km of spatial resolution) give the possibility to investigate three principal weather fields involved in extreme events conditions such as surface temperature, precipitation and wind velocity. For each of them the computation of several indicators has been done, at global and regional scale, on daily time basis over 4 seasons defined as December-February (DJF), March-May (MAM), June-August (JJA), September-November (SON). These indicators characterize each model grid point over the relative spatial model domain (global/regional). For each index we computed trend maps considering only grid points where the detected trend is statistically significant. Available trend maps are defined over five periods of 30 years: 1971-2000 1981-2010, 2011-2040, 2041-2070, 2071-2100, and two periods of 65 years: 1971-2035 and 2036-2100.