Space-time structure of extreme precipitation in Europe over the last century: a climate perspective

Historical observations show a significant change of globe temperature distribution as a consequence of global warming. In the midlatitude , and specifically in Europe, annual and seasonal changes of the midlatitude climate driving variables as EPG ( equator pole gradient) and OLC ( ocean land contrast ) were recorded, show significant trends, as shown in fig.1 and 2 . As a consequence of these changes a spatio-temporal trends in extreme precipitation in Europe is expected. We analyze over a century of continuous rainfall data available from the ECA&D archive for spatio-temporal trends in extreme precipitation. The data base includes 515 stations with records longer than 100 years. For each station, we identify daily rainfall events in the winter 6 months (Oct-Mar) that exceed the 99th percentile of daily rainfall. An annual time series of the frequency of such events is created, as well as an annual time series of the average daily rainfall in these events. Space and time analyses of the variation of the frequency and intensity time series are then pursued using multivariate time and frequency domain (multi-taper method) methods. The key trends and organized spectral modes identified can be related to potential anthropogenic change and to well established climate indices (e.g., NAO, EAWR and SL). The simultaneous analysis of monotonic trends over the secular period and quasi -oscillatory phenomena is informative as to the attribution of changes in extreme precipitation over the region.