A comparison of photospheric, chromospheric and coronal indices for the sun

Ronald Lynn Gilliland

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Indices of photospheric activity as reconstructed sunspot blocking (essentially sunspot areas) are compared with the White and Livingston 1Å Ca II K index and a polarization-brightness index of the corona that is proportional to mean hemispheric coronal electron density. The photospheric, chromospheric and coronal manifestations of magnetic activity associated with the solar cycle show quite similar behavior. The modulation properties of each index are remarkably similar both in terms of cycle signal-to-noise and the morphology of scatter variations with respect to cycle phase. The coronal electron density shows a more rapid rise from solar minimum to maximum than the activity indicators from lower atmospheric levels - suggesting a difference in growth rates for the large scale structures influencing the corona with respect to the smaller scale photospheric features.

Original languageEnglish (US)
Pages (from-to)69-72
Number of pages4
JournalAdvances in Space Research
Issue number8
StatePublished - Jan 1 1986

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering
  • Astronomy and Astrophysics
  • Geophysics
  • Atmospheric Science
  • Space and Planetary Science
  • General Earth and Planetary Sciences


Dive into the research topics of 'A comparison of photospheric, chromospheric and coronal indices for the sun'. Together they form a unique fingerprint.

Cite this