GCOS-funded five-year project about sunspot data concluded

At the end of July the five-year project funded by the Global Climate Observing System (GCOS) Switzerland, which involved the Specola Solare Ticinese and the ETH-Zurich University Archives, came to an end. The aim of the project was to digitise, preserve and disseminate the data, in both analogic (drawings) and digital format, the observations carried out at the Specola from its foundation in 1957 to the present day.

All original drawings are now safely stored in the Zurich archives and the high-resolution scans can be viewed on the e-manuscripta website (https://www.e-manuscripta.ch/). The complete database, updated to the present day, can be consulted freely of charge on the Specola website (https://www.specola.ch/) and contains data on all drawings and sunspot groups (number, counting, classification, coordinates). The database is also be downloaded from the Zenodo repository (https://doi.org/10.5281/zenodo.8117331) as benefit for the scientific community of solar physics or climatology, but also for anyone interested in research on our star.

Over the next few years, the project will continue thanks to funding from the Canton of Ticino through Swisslos funds, with the aim of further expanding the data collected in the database.

The completion of the project would not have been possible without the tireless, constant and patient collaboration of all the observers who, from 1957 to the present day, have served at the Specola. In particular, the authors wish to dedicate this result to the most prominent among them, namely Sergio Cortesi (1932-2021).

The project has been carried out with the support of the Federal Office of Meteorology and Climatology MeteoSwiss, in the framework of GCOS Switzerland.

The Specola would like to thank for their indispensable cooperation the ETH-Zurich University Archives and DigiCenter, in particular by Evelyn Boesch and Christian Huber, the staff of the Solar Influences Data Analysis Center (SILSO) who developed the DigiSun software and provided invaluable advice on a regular basis, in particular Frédéric Clette and Sabrina Bechet, and the staff of the Istituto ricerche solari Aldo e Cele Daccò (IRSOL Christian Skorski and Bruno Barbieri. The Specola Solare Ticinese is supported by funding from the Canton of Ticino through Swisslos funds.

José Roberto Canivete Cuissa concludes his PhD at IRSOL

José Roberto Canivete Cuissa successfully defended his thesis work «Numerical Simulations of Magneto-Convection: From Stellar Dynamos to Small-Scale Swirling Motions» on August 31, 2023 at the Institute for Computational Science of the University of Zürich. «Roberto» as he is commonly called, is from Riviera (TI) and carried out his doctoral thesis at IRSOL in the numerical simulations group of Oskar Steiner. His main topic of research was small swirling motions in the solar atmospheres that resemble terrestrial tornadoes but different from those are connected to magnetic fields. These magnetic tornadoes have been discovered by observations of the Sun only two decades ago.

Roberto analyzed numerical simulations of the solar atmosphere and discovered that these tornadoes are pulses of torsional Alfvén waves that propagate along magnetic lines of force in the vertical direction from the solar surface to the outer solar atmosphere. Thus, they can transport mechanical energy from the solar surface to the chromosphere and the corona, where they may dissipate and turn this energy into heat. On the way to this discovery, Roberto derived a novel hydrodynamic equation for the swirling strength, a quantity similar to the vorticity but better suited as a measure for the strength of vortical motion. He also created an innovative software tool for finding vortical motions in a two-dimensional flow-field (available under https://github.com/jcanivete/swirl) and he applied it to numerical simulations of the solar and stellar atmospheres for a statistical analysis. The SWIRL code can also be used in different fields of research, such as in local climate research as it was recently done. Beyond that, Roberto carried out magnetohydrodynamic simulations of stellar magneto-convection for which he modified the well-known simulation code RAMSES, making it fit for stellar and solar applications.

His results got published in five peer-reviewed articles in «Astronomy & Astrophysics», one of the highest regarded astrophysical journal. Furthermore, Roberto also substantially contributed to a review article on vortex motions in the solar atmosphere and to a scientific article that resulted from a student project at University of Zürich on intensity interferometry, both in peer-reviewed astrophysical journals.

At IRSOL, we congratulate  Dr. José Roberto Canivete Cuissa for his splendid achievements!

From left to right, Prof. Ravit Helled (academic supervisor), Dr. José Roberto Canivete Cuissa Dr.Oskar Steiner (research co-supervisor).