  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.
