A semi-automated method to reveal the evolution of each sunspot group in a solar cycle
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Sunspots are the most important indicator of the magnetic activity on the solar surface during a cycle. Every sunspot group is formed and shaped by the magnetic field of the Sun. Hence, the magnetic field intensity shows itself as the size of a sunspot group area on the surface. This shows that getting the development or evolution of sunspot groups over time means getting the change of magnetic field intensity during same interval. Here, to reveal the evolution of sunspot groups in a cycle, a method called Solar Cycle Analyzer Tool (SCAT) is presented. This method was developed as a part of Computer-Aided Measurements for Sunspots (CAMS) because the same subroutines and subprograms were used for calculations (Çakmak in Exp. Astron. 38:77–89, 2014). The developed software tracks sunspot groups every day and gives them the same group number. The confirmation is made by the user to prevent counting re-formations as a continuation of an old group in the same active region. With this method, the evolution of every sunspot group can be listed for each cycle year besides other cycle features like the daily and monthly sunspot relative numbers and distribution frequency of the sunspot group types. Since 2015, SCAT is being used to get data for the annual reports of Istanbul University Observatory.
KeywordsSolar cycle Sun: sunspots Sunspot group evolution
Thanks to Assoc. Prof. Dr. Nurol Al from the Department of Astronomy and Space Sciences, Faculty of Science, Istanbul University for the idea to prepare this article. Also, thanks to Res. Asst. Başar Coşkunoğlu for his contributions towards improving the language of the manuscript. Also, thanks to the anonymous reviewer for his/her valuable suggestions and comments improving the manuscript. This research made help of Istanbul University Observatory Sunspot Observations. This work supported by the Istanbul University Scientific Research Projects Commission with the project number 24242.