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AAVSO Solar Division Digital Data Archives at NGDC


Helen E. Coffey

Christine D. Hanchett

Edward H. Erwin



National Geophysical Data Center (NGDC)




The American Association of Variable Star Observers (AAVSO) Solar Division has maintained an active observing program for many years in the solar-terrestrial physics disciplines. Both the American sunspot number R(a) and the Sudden Ionospheric Disturbances (SIDs) are monitored routinely by an AAVSO worldwide network of observers. The data are compiled at a central point by a dedicated observer who merges all of the reduced data reports from the worldwide network and quality controls these records. A copy of these are sent to the National Oceanic and Atmospheric Administration (NOAA) National Geophysical Data Center (NGDC) in Boulder, Colorado, who archives and disseminates solar-terrestrial physics datasets. The NGDC archives for the R(a) reach back to 1946 and provide a valuable independant measure of the sunspot number. The SID reports from AAVSO begin in 1958 when the HGDC SID archive begins. We review these archives in the context of the National Space Weather Program.

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