Data rescue of national and international meteorological observations at Deutscher Wetterdienst

Historic observational data records are an important contribution to climate reconstructions and the analysis of past weather events. Particularly in remote and data sparse regions, such as the open ocean, newly rescued data can significantly improve the knowledge of weather and climatic conditions in earlier decades and centuries.Deutscher Wetterdienst (DWD) has several collections of original historical weather records from land stations and ships worldwide. They comprise not only observations from Germany, but also from the worlds oceans and land stations in many parts of the world.All German state-owned meteorological observations since the founding of the Prussian Meteorological Institute in 1848 are collected in DWDs main archive in Offenbach.DWDs office in Hamburg holds the marine archive, starting with the collections of the German Naval Observatory, 'Deutsche Seewarte', which existed from 1868 to 1945. It includes marine data records from ships and land stations in many parts of the world (e.g. from former German colonies), as well as signal stations situated at the coasts of the North and Baltic Sea.With increasing computing resources, high temporal resolution data has increasingly become the focus of climate research in recent years. Thus, the processing of such unique historical datasets creates considerable added value. The digitization of recording strips from pluviographs, for example, is currently one focal point of the data rescue activities at DWD.The documentation, digitization and quality check of the enormous amount of handwritten journals of the data archives is still ongoing. The digitized data are freely accessible to the scientific community and are also continuously submitted to international data archives, such as ICOADS and ISPD. These datasets also make the data an important input for regional and global reanalyses.The presentation will give an overview of the historical archives of Deutscher Wetterdienst. The challenges are discussed the latest progress of the digitization efforts and ongoing analysis of the data shown.