Variazioni meteomarine recenti e climatologia dinamica nel bacino adriatico: primi risultati

Abstract Recent sea level variations are a key indicator of global climate change. Estimating sea-level rise is one of the most important scientific issues, with a potential large positive social impact. The Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC), underlines the importance of instrumental records to analyse recent sea-level changes. The relatively intense warming recorded throughout the latest 40 years - with widespread ice melting and relative glacial-hydro-isostatic rearrangement - has however induced global sea level rise ranging around 1.2-2.0 mm/yr. In the Mediterranean Sea, this value is significantly lower (approximately by 35%) than the global mean value. Likely, this is due to the Northern Atlantic Oscillation (NAO), inducing at the Adriatic latitudes an evident increase of atmospheric pressure and temperature, as well as of salinity variation; also taking into account the specific features of this almost closed shallow sea. However, relative sea level rise (RSLR) occurred along the entire shorelines of the Northern Adriatic Sea, locally interfering with land subsidence, both natural and man-induced, and eustasy. Their combined effect has produced relative ground settlements ranging from centimetres to meters. Aim of this study is to analyse the historic series of meteo-marine records for 12 measuring stations, belonging to the National Tidal Network organized by ISPRA, located between Trieste and Otranto in order both to verify trends in sea level variations and to identify the most significant storm events occurred from 2010 to 2015. Synoptic situations responsible for these intense events for each sector of the basin have been analysed too. Persistence of subtropical high pressure conditions alternated with higher frequency of cyclogenesis have been detected for almost every month on both the northern Adriatic basin and the medium and high Tyrrhenian; this most likely is due to the increase of sea surface temperatures: around at 0.8 °C in the last fifteen years. Keywords: climate change, rising average sea level, Adriatic Sea, cyclogenesis, storm surges