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Action Team: Coronal Hole Boundary Working Team

Team ID: S2-01

Team Leads:

Lead: Martin Reiss (Space Research Institute IWF, Graz, Austria),

Co-Lead: Karin Muglach (NASA GSFC, USA),


The ambient solar wind flows, and the magnetic fields embedded within it, are driven by the Sun's magnetic field. Thus, studying the magnetic field configuration in the solar atmosphere is of key importance for improving the understanding and ultimately improve the predictions of the evolving space weather from Sun to Earth. The magnetic configuration of open field lines along which solar wind flows accelerate to supersonic speeds, commonly known as coronal holes, is especially important for predicting key properties in the interplanetary space such as solar wind bulk speed, magnetic field strength, and field orientation. Additionally, the dynamic evolution of coronal hole boundaries is understood as having a critical role in the origin of the slow solar wind. Coronal holes in EUV and X-Ray images are an important diagnostic of the magnetic field configuration of the Sun and are a key observational test for numerical models of the ambient solar wind. Despite the importance of these solar phenomena, there has been no detailed investigation of the strengths and weaknesses of automated coronal hole detection schemes. 


The objectives of this action team are threefold: First, to study and compare different automated coronal hole detection schemes with open communication with the space weather community. Second, to develop strategies to quantitatively assess the spatial and temporal uncertainty of coronal hole boundary locations. Third, to use this information to further improve the predictive capabilities of ambient solar wind models.

Action Items:

  • Establish a database of CH candidates based on different automated coronal hole detection schemes.
  • Define metrics to assess the uncertainty of coronal hole boundaries in EUV and X-Ray images of the Sun to better understand the advantages/disadvantages of these techniques.
  • Develop strategies to assess the uncertainty of CH boundary locations in ambient solar wind models.
  • Develop strategies to inform/constrain ambient solar wind models and enhance their predictive capabilities.


  • The Observational Uncertainty of Coronal Hole Boundaries in Automated Detection Schemes. M. A. Reiss, K. Muglach, C. Möstl, C. N. Arge, R. Bailey, V. Delouille, T. M. Garton, A. Hamada, S. Hofmeister, E. Illarionov, R. Jarolim, M. Kirk, A. Kosovichev, L. Krista, S. Lee, C. Lowder, P. J. MacNeice, A. Veronig, and Coronal Hole Boundary Working Team Members. The Astrophysical Journal, March 2021. [Open Access]


Show/Hide Team S2-01 Participants

Lucia Abbo (INAF - Osservatorio Astrofisco di Torino, Italy)
Hamada Amr (University of Oulu, Finland)
C. Nick Arge (NASA/GSFC, USA)
Stefano Bianco (GFZ Potsdam, GERMANY)
Laura Boucheron (New Mexico State University, USA)
Ronald Caplan (Predictive Science Inc., USA)
Shibaji Chakraborty (Virginia Tech, USA)
Yaireska Collado-Vega (NASA/GSFC, USA)
Nour Dahmen (ONERA, France)
Jeremy Grajeda (New Mexico State University, USA)
Amr Hamada (University of Oulu, Finland)
Stephan Heinemann (Max-Planck Institute for Solar System Research, Germany)
Carl Henney (AFRL - Air Force Research Laboratory, USA)
Stefan Hofmeister (Columbia Astrophysics Laboratory, Columbia University, USA)
Egor Illarionov (Lomonosov Moscow State University, RUSSIA)
Fadil Inceoglu (GFZ Potsdam, GERMANY)
Robert Jarolim (University of Graz, AUSTRIA)
Jaehun Kim (Korean Space Weather Center, KOREA)
Michael Kirk (NASA/GSFC, USA)
Yuan-Kuen Ko (NRL - Naval Research Laboratory, USA)
Alexander Kosovichev (New Jersey Institute of Technology, USA)
Sangwoo Lee (Korean Space Weather Center, KOREA)
Jon Linker (Predictive Science Inc., USA)
Chris Lowder (Southwest Research Institute, USA)
Janet Luhmann (UC Berkeley - University of California Berkeley)
Peter MacNeice (NASA/NSF Community Coordinated Modeling Center (CCMC), USA)
Maria Madjarska (Max-Planck Institute for Solar System Research, Germany)
Emily Mason (NASA/GSFC, USA)
Karin Muglach (NASA/GSFC, USA)
Olga Panasenco (Advanced Heliophysics Inc., Pasadena CA, USA)
Martin Reiss (Space Research Institute - SRI, Graz, AUSTRIA)
Sam Schonfeld (Boston College Institute for Scientific Research, USA)
Dibyendu Sur (Institute of Radio Physics and Electronics, University of Calcutta, India)
Manuela Temmer (University of Graz, AUSTRIA)
Astrid Veronig (University of Graz, AUSTRIA)
Yi-Ming Wang (NRL - Naval Research Laboratory, USA)