Authors: J J Curto J G Solé M Genescà M J Blanca J M Vaquero
Publish Date: 2016/08/03
Volume: 291, Issue: 9-10, Pages: 2587-2607
Abstract
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 CS428 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 conditionsThe authors wish to express their gratitude for the work done by the solar observers at the Ebro Observatory throughout its long history – a human chain that has provided an invaluable historical series of over one hundred years We dedicate this article to all of these observersAs regards international data we thank the World Solar Data Centre WDC at the Royal Observatory of Belgium for its work in collecting filtering and storing the data it receives regularly from collaborating centres and all the infrastructure it has in place for users to be able to freely download solar data from its web SILSOWe also thank the National Oceanic and Atmospheric Administration NOAA which provides a huge amount of geophysical and solar data that are essential for studies in the field of space weather and the TOSCA project ESSEM COST action ES1005 of the European Union
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