New Solar Cycle Charts Now Reflect The Revised Sunspot Counting System.

bigspotfd_thumbRevised Sunspot number as discussed in previous posting of July 2015 numbers can be seen below:new #solarterrestialjuly

Below is the Sunspot number posted before the numbering was changed to match the new criteria discussed in the “Sunspot Number History Change Is Underway“.


The only thing different is the green line the “30 day Wolf Number. The new number is greater than the old one.

Quoting SILSO: “In the values themselves, the most prominent change will result from the elimination of the 0.6 factor formerly used by the Zürich Observatory to scale the modern numbers down to the scale of the initial Wolf observations. This factor has always led to some confusion and now has lost its sense more than 130 years after Wolf’s observations. This change will thus raise the scale of the entire sunspot number time series by a factor 1/O.6, which may significantly affect software using the sunspot number as input.”



2 responses to “New Solar Cycle Charts Now Reflect The Revised Sunspot Counting System.

  1. There is a lot more to the 400-yr sunspot record recalibration than just a general shift upward in the International Sunspot Number.

    Comparing the revised new record to the old record shows these primary differences:
    1-All counts increased by 1/0.6 (Old Wolf baseline replaced with Wolfer baseline)
    2-Counts after 1947 are reduced (error correction)
    3-The old record and new match between 1890 and 1946
    3-Counts prior to 1890 increased (mostly 1/0.6, but some error correction and newer-found data)
    4-Over it’s 400-yr history, sunspot occurrences are relatively constant except for big dips that happened about every 100 years. We are entering the 4th dip.

    In the re-calibrated ISN, Cycle 24 now becomes the 4th lowest peak since 1755. Previously it was the 7th lowest.

    But most important…
    For the first time ever, the Belgium Observatory includes the group number record that goes all the way back to 1610. It’s a completely new rebuild of that record which corrects and improves on the Hoyt and Schatten 1998 data series.

    The group number data series probably has more physical meaning than the International Sunspot Number does. It correlates to F10.7, sunspot area, magnetism and other properties associated with solar activity.

    For the first time, the sunspot record is consistent with other measures of solar activity. That will improve the accuracy of sunspot/climate science studies, among many other things. About 100 papers a year use the sunspot record as a data source.

  2. I finally wrote a first reaction article assessing my take on the significance of the recalibration of the solar sunspot record. It is here:

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