Datensatz

Zusammenfassung

A large collection of photographic paper magnetograms, covering globally an entire century is preserved in the archives of Chambon-la-forêt magnetic observatory, France. It contains magnetograms from various instruments and observatories: the National magnetic observatory (it moved from Parc-Saint-Maur, to Val-Joyeux, to Chambon-la-forêt), Bangui (Central African Republic), M’bour (Senegal), Pamatai (French Polynesia), and other observatories in metropolitan France at the beginning of the 20th century. Only values from tables of hand-written hourly values from the National magnetic observatory and overseas observatories had been digitised and made available to the scientific community. In order to access additional information on the magnetic variations recorded on the magnetograms, we developed a recovering software: RECOV. It is based on MATLAB and can be run either as a MATLAB App, or as a standalone desktop application, with MATLAB Runtime. It provides an interface for manual selection of magnetic traces that are converted into magnetic variations and calibrated time series, if definitive hourly time series are available. The user can recover magnetograms of different quality, even cases when the magnetic traces cross the temporal axis, or wrap-around traces appear during the strongest storms. We aim obtaining recovered time-series with sampling every minute, with a reliability depending on the size and resolution of magnetic traces. We present results of recovered magnetic variations during magnetic storms of 1958 and comparisons between different instruments.