Digitizing historical daily weather bulletins through citizen scientists: The ReData project

In recent decades, numerous climate data rescue programs have begun in many countries worldwide. These projects aim to preserve data recorded on paper sheets, which are vulnerable to deterioration, and to make them accessible to the scientific community. This enhances the accuracy of climatological studies and historical reconstructions, including those focused on specific events. This study presents the designed framework developed in the ReData (Recovery of Data) project, launched by the Meteonetwork association in collaboration with the University of Milan in 2017, and upgraded in 2024 on the Zooniverse platform, which engages volunteers in scientific research activities; in particular, it showcases the methodology implemented for this climate data rescue initiative. The job leverages the potential of citizen science to digitize meteorological data, collected by the Italian Royal Central Meteorological Office (RCMO) from 1879 to 1940 and published in daily meteorological bulletins, on a platform specifically designed to facilitate large-scale digitization and ensure user accessibility. In addition, as a practical application of digitized data, a case study is presented involving a synoptic reconstruction of the flood event that affected the River Adige in northeastern Italy in September 1882. The overall project provides critical data for reanalysis models, and it enhances the understanding of historical climate trends over the Italian peninsula, offering significant cultural and scientific value.