DATE2018-05-19 11:50:56
AUTHORSP Lionello (1,2), L Scarascia (2)
  1. Univ. Of Salento, Lecce, Italy
  2. CMCC, Lecce, Italy
ABSTRACTThis contribution analyzes a large ensemble of CMIP5 global climate projections in order to link future regional climate change in the Mediterranean region and differences between north and south area to the global mean annual surface temperature change. Warming will be particularly large in summer (approximately 50% larger than global mean annual warming) and for the land areas located north of the basin (locally up to 100% larger than global warming). Reduction of precipitation will affect all seasons in the southern Mediterranean areas, with maximum reduction for winter precipitation (-7 mm/k or -7%/k), but mostly summer in the northern Mediterranean areas (-7mm/K or -9%/K). Areas located at the northern border of the Mediterranean region will not experience a reduction of precipitation in winter. Contrast between north and south areas will be even stronger than this for indices associated with extremes of precipitation and hydrological cycle. On this respect, it appears that climate change will significantly amplify differences between North and south regions. As global mean annual temperature increases, in the North Mediterranean the Simple Daily precipitation Intensity Index (SDII) and the total precipitation during very wet days (R95P) increase at a rate of approximately 0.1mm/K and 5mm/K, respectively, while the same indices show no relevant change in the southern Mediterranean. The maximum number of consecutive dry days (CDD) is already larger in the Southern than in the Northern Mediterranean and it is increasing faster in the former than in the latter as global warming increases (rates are about 8days/K and 5days/K) respectively. The maximum number of consecutive wet days (CWD) is larger in the northern than in the southern Mediterranean and decreasing at a similar rate (about 0.5 days/K) in both (actually the rate of decrease is slightly smaller in the south). At difference with the response of the regional hydrological cycle extremes to global warming, changes of warm nights (TN90p) and cold days (TX10p) are similar in the North and South Mediterranean. In both areas, the increase of warm nights is dramatic, to the extent that with a 4K global warming almost all nights would classified as warm nights and there will be no cold days (definitions of cold days and warm nights are based on the 1961-1990 reference period)