Composite Magnesium-II Core-to-Wing Index
The Mg II Index is a proxy for solar chromospheric variability. This composite data record is based on the work of Viereck et al. (2004) Space Weather, vol 2, CiteID S10005 for measurements from 1978 through 2003. Starting in 2003, the data from SORCE SOLSTICE is used exclusively. The SOLSTICE spectra have been convolved with a 1.1 nm triangular response function to improve the long-term agreement with other measurements. All of the data sets have been normalized to a common scale to create a single long-term record.
For more information about this data set, see the SORCE web site.