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The Non-Conforming Cycle 24

In this extensive study from April 2016, the behavior of Solar Cycle 24 is analyzed through various solar indices and instruments, revealing discrepancies in data related to sunspots, magnetic flux, and total solar irradiance. Collaborative efforts from experts Monica Bobra and Xudong Sun shed light on the unusual patterns of Cycle 24, including high CME frequency, elevated TSI levels, and magnetic field intensities not aligning with sunspot numbers. The study also discusses the challenges of calibrating instruments and reconstructing TSI data during this unique solar cycle. Insights from the Solar Cycle 24 research are presented, highlighting the distinct characteristics that set it apart from previous cycles.

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The Non-Conforming Cycle 24

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  1. The Non-Conforming Cycle 24 Leif Svalgaard Stanford University April 2016 With help from Monica Bobra and Xudong Sun

  2. TSI Low in 2013-2014 Mean Field TSI HMI Continuum F10.7 2014-02-03 SN Kanzelhöhe Drawing because of several large sunspots

  3. The Large Spots were a Source of Strong Magnetic Flux HMI That helped reverse and rebuild the polar fields

  4. The Large Spots Took a Bite out of Total Solar Irradiance (TSI) Composite of several instruments scaled to SORCE/TIM (LASP)

  5. The Usual Solar Indices all Agree Sunspot Number, Group Number, F10.7 Flux, Mg II flux, Sunspot Areas all scaled to the Sunspot Number (V2)

  6. Matching Indices on Cycle 23 Shows Disagreements for Cycle 24

  7. CME Rate Followed SN… CMEs are filaments lifting off Webb Tucson 2013 Christina Kay, SC-6, 2016 CME /day SSN 21 22

  8. But no Longer in Cycle 24 23 24 G. Petrie, SC-6, 2016

  9. The Sun’s global magnetic pattern is closely related to the sunspot number (Stenflo, SSN WS Locarno, 2014) MDI Magnetograms Stenflo, 2014

  10. During Cycle 23 the Sunspot Number was Well Described by the Magnetic Flux “There is a nearly one-to-one relation between the disk-averaged unsigned flux density and the sunspot number.” SSN curve fit “The dashed curve is the second-order fit function in terms of the sunspot number Rz: b0 + b1 Rz + b2 Rz 2, where b0 (=2.7 G) represents the average unsigned flux density in the absence of sunspots.” 23

  11. But the Fit is Breaking Down in 2015 24 This is for SOLIS (http://solis.nso.edu/0/vsm/vsm_mnfield.html)

  12. Similar Finding for WSO

  13. And for HMI on SDO The correspondence between HMI and the Sunspot Number [before October 2014 is quite remarkable.

  14. Correct Calibration is Always a Problem Since May 2006, the calibrations of WSO and SOLIS seem to agree reasonable well, although not perfectly

  15. So, Perhaps, there is something going on with Cycle 24

  16. Reconstructing TSI from the Group Number Problem 2003-2015 The TSI Experimenters agree that the problem is not instrumental

  17. Conclusion • Cycle 24 is behaving differently from previous cycles: • CME frequency too high • TSI too high • Magnetic field too high [at least since late in 2014] compared to Sunspot Number

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