Reexamination of the Coronal Index of Solar Activity
Abstract
The coronal index (CI) of solar activity is the irradiance of the Sun as a star in the coronal green line (Fe XIV, 530.3 nm or 5303 A). It is derived from ground-based observations of the green corona made by the network of coronal stations (currently Kislovodsk, Lomnicky Stit, Norikura, and Sacramento Peak). The CI was introduced by Rybansky (1975) to facilitate comparison of ground-based green line measurements with satellite-based extreme ultraviolet and soft X-ray observations. The CI since 1965 is based on the Lomnicky Stit photometric scale; the CI was extended to earlier years by Rybansky et al. (1994) based on cross-calibrations of Lomnicky Stit data with measurements made at Pic du Midi and Arosa. The resultant 1939-1992 CI had the interesting property that its value at the peak of the 11-year cycle increased more or less monotonically from cycle 18 through cycle 22 even though the peak sunspot number of cycle 20 exhibited a significant local minimum between that of cycles 19 and 21.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 25, 2005
- Accession Number
- ADA444269
Entities
People
- Edward W. Cliver
- L. Klocok
- M. Minarovjech
- M. Rybansky
- V. Rusin
Organizations
- Air Force Research Laboratory