IAU Focus Meeting FM9:
Solar Irradiance: Physics-Based Advances

August 22 – 23, 2018



  • Robert Cameron - Max-Planck-Institut für Sonnensystemforschung, Göttingen, Germany
  • Paul Charbonneau - Université de Montréal, Quebec (QC), Canada
  • Ilaria Ermolli - Osservatorio Astronomico di Roma, Roma, Italy
  • Juan Fontenla - NorthWest Research Associates, Boulder, USA
  • Mark Giampapa - National Solar Observatory, USA
  • Jie Jiang - Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing, China
  • Greg Kopp - Laboratory for Atmospheric and Space Physics, Boulder, USA (co-chair and co-editor of proceedings)
  • Matthieu Kretzschmar - Univ. of Orleans & CNRS, Orléans, France
  • Natalie Krivova - Max-Planck-Institut für Sonnensystemforschung, Göttingen, Germany
  • Werner Schmutz - Physikalisch-Meteorologishes Observatorium Davos, World Radiation Center, Switzerland
  • Alexander Shapiro - Max-Planck-Institut für Sonnensystemforschung, Göttingen, Germany (co-chair & co-editor of proceedings)
  • Yvonne Unruh - Blackett Laboratory Imperial College London, UK
  • Ilya Usoskin - University of Oulu, Oulu, Finland
  • Aline Vidotto - Trinity College Dublin, Ireland


Scientific Rationale:

Understanding and modeling of solar-irradiance variability is important not only for solar physics but also for solar-terrestrial and solar-stellar studies. The latest irradiance measurements call into question aspects of currently-available empirical and semi-empirical models of solar-irradiance variability. A new generation of significantly more realistic physics-based irradiance models can now be created to incorporate recent advances in modeling and observing the solar atmosphere. This next generation of irradiance models will include new advances in MHD, surface flux transport, and radiative transfer simulations as well as new state-of-the-art solar data. By relying on physics-based understandings rather than merely empirical relationships established for the Sun, these new models will also allow more direct and physical extrapolations to other stars, opening a new regime for solar-stellar connection studies, as well as improved long-term estimates of historical solar variability.



  • Overview of existing solar-irradiance datasets (models and observations)
  • Proxies of long-term solar magnetic activity 
  • State-of-the-art in solar-irradiance modeling 
  • Simulations of solar surface magnetic field distribution with surface flux transport models 
  • Structure of solar magnetic features: What can we learn from MHD simulations? 
  • Radiative transfer calculations for next generation of irradiance models 
  • Brightness contrasts of solar magnetic features from high-resolution solar imagery (SUNRISE, SDO, HINODE, etc.) 
  • Solar-irradiance variability on timescales less than a day: magnetic and non-magnetic components 
  • Can we use solar models to explain brightness variations of Sun-like stars? 
  • Climate research needs for solar-irradiance time series: temporal and spectral coverage, critical issues, and priorities



Greg Kopp:

Alexander Shapiro:


Link to External Website:





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