Solar Calcium Plage Data

1.) DATA --
1a.) Mt. Wilson Daily Calcium Plage Areas and Calcium Network Areas Apn Data 1915-1999 (Foukal)
1b.) San Fernando K-line Facular Data 1988-1998 (Daily areas and irradiance indices -- Chapman)
1c.) McMath/Hale/Big Bear daily observations 1942-1987 (positions, areas -- Dodson-Prince) NASA SPDS and NOAA ESDIM Data Rescue

2.) INDEX -- Daily Summary Data from McMath/Hale/Big Bear 1942-1987
Daily Big Bear Calcium K-line Filtergram Index 1996-1997
Daily Sacramento Peak Calcium Index 1976-2002

3.) SGD Table -- Regions of Solar Activity 1969-1982 -- table that appeared routinely in the monthly report Solar-Geophysical Data -- white light sunspot regions are tied to overlying Calcium plage regions

Solar Calcium Data (All ftp)

For many years, solar observatories have monitored the Sun in the calcium (Ca) K line wavelength by using a filter that allows only this wavelength's light through, calcium filtergrams, or spectroheliograms. Daily full disk calcium K232 images are reduced to provide calcium plage positions and areas or summed to produce a daily Ca K index. Ca K active regions can be seen moving across the solar disk, above the white light sunspot regions, and higher in the solar atmosphere (chromosphere).

1a.) Daily Calcium Plage Areas and Network Areas from Mt. Wilson Observatory Apn Data 1915-1999 -- Peter Foukal
  • The Apn data include both the Active Region (AR) calcium plage areas, as in the Ap, and also the areas of the active network. The Apn is NOT corrected for foreshortening (useful for irradiance models) and so is expressed in fractions of the solar disk. The basic reduction procedure is given in GRL 25, 2909 (1998), but the values were revised somewhat in a later paper in GRL 29, 2089 (2002). The annual means of these data agree very well with the independent time series of the Mt. Wilson areas by Ulrich et al., and by Tlatov et al. -- see paper by P. Foukal, Solar Physics 255, 229 (2009). The data are plain text files of monthly mean and annual mean values of (plage + active network) areas, covering the period 8/1915 - 12/1999 inclusive, and expressed as fractions of the solar disc (i.e. not corrected for foreshortening). Data prior through 1984 are means of daily Mt. Wilson measurements; data after 1984 are based on four roughly evenly spaced days per month using Sacramento Peak observations.
  • Monthly Calcium Plage and Network Areas (in fractions of solar disk) in data and plot (pdf file) form
  • Smoothed Monthly Calcium Plage and Network Areas (in fractions of solar disk) in data and plot (pdf file) form
  • Plot of both the smoothed and unsmoothed Apn with International Sunspot Number -- Calcium Plage and Network Areas (in fractions of solar disk) plot

1b.) San Fernando Observatory K-line facular data -- Gary Chapman
1c.) Daily calcium plage reduced data, including position, areas and intensities. Solar observatories contributing to this database include McMath Solar Observatory (1942-Sep 1979), Hale Observatory (Mt. Wilson Solar Observatory -- Oct 1979-Sep 1981), and Big Bear Solar Observatory (Oct 1981-Oct 1987) NASA SPDS and NOAA ESDIM Data Rescue
2a. Daily summary data of the McMath/Hale/BigBear database 1942-1987 -- includes YYMMDD, number of plage regions, total corrected plage area, and Calcium plage index for that day.
2b. Big Bear Solar Observatory Calcium K Index
2c. Sacramento Peak Solar Observatory Daily Calcium K Index

3. SGD Table -- Solar-Geophysical Data Regions of Solar Activity Table 1969-1982