Historical Heliophysical Series of the Ebro Observatory

We present the contents of the historical heliophysical series collected at the Ebro Observatory, as well as the actions carried out to restore and save these data and to conserve the physical media containing the data and the telescopes that helped to obtain them. We also discuss the results obtained with these measurements, describe how we disseminated them, and report on the investigations that we have carried out with this information. We show the evolution of the local solar indices such as the Ebro Sunspot Number (ESN), the Ebro Group Sunspot Number (EGSN), or the Ebro Sunspot Area (ESA), which are derived directly from our data. For verification purposes, these local solar indices have been compared to the international sunspot numbers published by SILSO. Our data are reliable and correlate well with the respective international series. Finally, as an example of the possibilities that the Ebro series offer, we explain the use of these data to elucidate one of the recent problems in solar physics: the discontinuity in international data known as the Waldmeier discontinuity and, in general, the ratio between sunspots and sunspot groups. In the Ebro Observatory series, no discontinuity such as this is detected. We instead observe a rather stable ratio in the spot or group rates. This result is in agreement with the hypothesis of Svalgaard (2010, ASP CS-428, 297) that the Waldmeier discontinuity is produced only on a procedural level, perhaps by a change in the criteria used in Zürich by Waldmeier or by changing external conditions.