University of Oulu

Martin A. Reiss et al 2021 ApJ 913 28,

The observational uncertainty of coronal hole boundaries in automated detection schemes

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Author: Reiss, Martin A.1; Muglach, Karin2,3; Möstl, Christian1;
Organizations: 1Space Research Institute, Austrian Academy of Sciences, Graz, Austria
2Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
3Catholic University of America, Washington, DC 20064, USA
4Conrad Observatory, Zentralanstalt für Meteorologie und Geodynamik, Vienna, Austria
5Royal Observatory of Belgium, Brussels, Belgium
6University of Southampton, Southampton, UK
7Space Physics and Astronomy Research Unit, Space Climate Group, University of Oulu, Oulu, Finland
8University of Graz, Institute of Physics, Graz, Austria
9Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA
10Moscow State University, Moscow, 119991, Russia
11Moscow Center of Fundamental and Applied Mathematics, Moscow, 119234, Russia
12ASTRA llc, Louisville, CO 80027, USA
13Center for Computational Heliophysics, New Jersey Institute of Technology, Newark, NJ 07102, USA
14Department of Physics, New Jersey Institute of Technology, Newark, NJ 07102, USA
15NASA Ames Research Center, Moffett Field, CA 94035, USA
16Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA
17National Centers for Environmental Information, National Oceanic and Atmospheric Administration, Boulder, CO 80305, USA
18Korean Space Weather Center, Jeju, Republic of Korea
19Southwest Research Institute, Boulder, CO, USA
20Kanzelhöhe Observatory for Solar and Environmental Research, University of Graz, Graz, Austria
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 6 MB)
Persistent link:
Language: English
Published: IOP Publishing, 2021
Publish Date: 2021-07-07


Coronal holes are the observational manifestation of the solar magnetic field open to the heliosphere and are of pivotal importance for our understanding of the origin and acceleration of the solar wind. Observations from space missions such as the Solar Dynamics Observatory now allow us to study coronal holes in unprecedented detail. Instrumental effects and other factors, however, pose a challenge to automatically detect coronal holes in solar imagery. The science community addresses these challenges with different detection schemes. Until now, little attention has been paid to assessing the disagreement between these schemes. In this COSPAR ISWAT initiative, we present a comparison of nine automated detection schemes widely applied in solar and space science. We study, specifically, a prevailing coronal hole observed by the Atmospheric Imaging Assembly instrument on 2018 May 30. Our results indicate that the choice of detection scheme has a significant effect on the location of the coronal hole boundary. Physical properties in coronal holes such as the area, mean intensity, and mean magnetic field strength vary by a factor of up to 4.5 between the maximum and minimum values. We conclude that our findings are relevant for coronal hole research from the past decade, and are therefore of interest to the solar and space research community.

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Series: Astrophysical journal
ISSN: 0004-637X
ISSN-E: 1538-4357
ISSN-L: 0004-637X
Volume: 913
Issue: 1
Article number: 28
DOI: 10.3847/1538-4357/abf2c8
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: The authors thank Maria Kuznetsova, Mario Bisi, Hermann Opgenoorth, and the cluster moderators for their commitment to the COSPAR ISWAT initiative, which supported this research effort. M.A.R. thanks NASA's Community Coordinated Modeling Center for financial travel support. The authors acknowledge the following organizations and programs: M.A.R., C.M., and R.L.B. acknowledge the Austrian Science Fund (FWF): J4160-N27, P31659, P31521; K.M. acknowledges support by the NASA HGI program (# 80HQTR19T0028) and the NASA cooperative agreement NNG11PL10A; A.V. and R.J. acknowledge the European Union's Horizon 2020 research and innovation program under grant agreement No. 824135 (SOLARNET). The results of the CHRONNOS code have been achieved using the Vienna Scientific Cluster (VSC) and the Skoltech HPC cluster ARKUDA. E.I. acknowledges the RSF grant 20-72-00106.
Copyright information: © 2021. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s)and the title of the work, journal citation and DOI.