The Variability of the Sun and Its Terrestrial Impact (VarSITI) was the SCOSTEP’s 5-year international program in 2014-2018. VarSITI focused on the recent and expected future solar activity and its consequences for the Earth, for various timescales from the order of thousands years to milliseconds, and for various locations and their connections from the solar interior to the Earth’s atmosphere. Four scientific projects were carried out under the VarSITI program: (1) Solar Evolution and Extrema (SEE), (2) International Study of Earth-Affecting Solar Transients(ISEST/MiniMax24), (3) Specification and Prediction of the Coupled Inner-Magnetospheric Environment (SPeCIMEN), and (4) Role Of the Sun and the Middle atmosphere / thermosphere / ionosphere In Climate (ROSMIC). These four projects were carried out in collaboration with relevant satellite and ground-based missions as well as modeling efforts to facilitate the implementation of these projects. This special issue mainly invites review papers on scientific achievements obtained from the 5-year VarSITI activities and the relevant topics to address possible future directions of these fields.
Kazuo Shiokawa, Nagoya University,Japan
Katya Georgieva, Bulgarian Academy of Sciences, Bulgaria
Nat Gopalswamy, NASA Goddard Space Flight Center, USA