Rescue of the 1873-1922 high and low waters of the Porto Corsini/Marina di Ravenna (northern Adriatic, Italy) tide gauge

The historical data corresponding to the period 1873-1922 of the Porto Corsini (northern Adriatic, Italy) tide gauge have been retrieved from the archive of the Italian Istituto Geografico Militare, in Florence (http://www.igmi.org). The data consist of daily high and low waters, which were recorded in six handwritten volumes. The 1873-1896 observations were, until now, totally unknown since they were never published, while, for the remaining years, only monthly mean values were available. We digitized and quality controlled the rescued data. Searching in different archives, we also found detailed information on the three sites occupied by the tide gauge within the Porto Corsini/Marina di Ravenna harbor. In addition, the rescue of the leveling data and of the datum definition made it possible to realize a homogeneous time series of monthly mean sea-level values, which now spans 144 years. Sea-level time series exceeding a century are rare, and they are most important because they provide key information for studying climate change-related processes. The Porto Corsini/Marina di Ravenna area is affected by natural subsidence, much enhanced by anthropogenic activities during the period 1940-1980, in particular. Using leveling, GPS and InSAR data we have modeled the subsidence behavior over the 1873-2016 period. After removing the subsidence from the series of monthly mean values, we estimated a long-period linear sea-level rise of + 1.25 ± 0.16 mm/year.