Ilya G. Usoskin

The 2018 Julius Bartels Medal is awarded to Ilya G. Usoskin for his key contributions to long-term changes of cosmic rays and solar activity, qualifying him as a founder of the space climate discipline.

Ilya Usoskin is one of the most eminent cosmic-ray scientists, provided ground-breaking contributions to the heliosphere, long-term changes in solar activity and solar-terrestrial relations. His recent review paper, ‘History of solar activity over millennia’, is rapidly becoming the definitive work on the topic.

His main contribution to the field is the reconstruction of the state of the Sun and heliosphere over long timescales by analysing isotopes generated by energetic particles and stored in tree rings, ice sheets, meteorites and moon rocks. Another good example of both his inventiveness and his deep understanding has been the recent development of a robust and reliable method of calibrating sunspot number series from the records of historic observers. These achievements have greatly improved our understanding of space climate over past millennia and have given better inputs to model simulations of both terrestrial and space climate.

Usoskin’s research methods are highly interdisciplinary. For example, he considers the geomagnetic and heliospheric field evolutions, cosmogenic isotope production mechanisms, and the effects of their deposition while modelling the impact on the atmosphere. Collectively, his research forms an outstanding and fundamental advancement in our understanding of Earth’s radiation environment and how it is influenced by the solar magnetic dynamo. The range of his scientific achievements can be measured by his 260 publications in international refereed journals, his continually growing 6500 citations and his H-index of 41.

Usoskin’s scientific work has been recognised with honours and awards, including the Knight, 1st class, of the Order of the Lion of Finland (2013), UNESCO Personal Award for Research in the Basic Sciences (1997), Award of the International Science Foundation for scientists of the former USSR (1993). Besides his scientific achievements, Usoskin has played key roles in servicing the space community. Shortly after his PhD from the University of Oulu in 2000 he became Head of their Cosmic Ray Station, which is an excellent facility for researchers in the field and, with his Oulu colleague Kalevi Mursula, he has organised the highly successful International Space Climate Symposia series. Now, as full professor, he is Vice-Director of the ReSoLVE (Research on SOlar Long-term Variability and Effects) Centre of Excellence of the Academy of Finland.

Awarding the EGU Julius Bartels Medal to Usoskin is particularly appropriate given his outstanding scientific contributions and his services to the community.