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The New Sunspot Group Number and TSI

This research explores the relationship between sunspot group number, EUV, and total solar irradiance (TSI) to reconstruct solar activity. However, it highlights a deviation in the relationship in the year 2015, warranting further investigation.

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The New Sunspot Group Number and TSI

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  1. The New Sunspot Group Number and TSI Leif Svalgaard Stanford University, California, USA http://www.leif.org/research SORCE, Savannah, Nov. 2015 WSO

  2. The open solar magnetic flux (OSF) is the main heliospheric parameter driving the modulation of cosmic rays. The OSF has been modeled by quantifying the occurrence rate and magnetic flux content of coronal mass ejections fitted to geomagnetic data. The OSF and the cycle-variable geometry of the heliospheric current sheet allows reconstruction of the cosmic ray modulation potential, φ. Newly Revised Reconstructions of Solar Activity Ilya G. Usoskin et al. Astronomy & Astrophysics, July 21, 2015 The ‘Space-Age’ has been rather typical of the last 300 years

  3. Solar Activity Cycle 24

  4. Composite of TIM, PMOD, and TCTE

  5. It seems that TSI no longer follows SSN nor F10.7Is this for real?

  6. Reconstructing TSI from the Group Number Problem 2003-2015

  7. Reconstructing F10.7 Flux from Geomagnetic Diurnal Variation Range 7

  8. Physics Behind the Diurnal Variation Electron density J = production ~ EUV EUV ~ F10.7 ~ rY1/2 Range rY

  9. EUV (λ<100 nm) Closely Follows Group Sunspot Number If EUV follows the Group Number we would expect TSI to also do that

  10. Conclusions • The new sunspot group number allows reconstruction of TSI since ~1600 under the assumption that the variation of TSI is linear in solar activity • The relationship fails for the year 2015. Why? • Reconstruction of EUV since ~1740s supports the TSI reconstruction if we assume that EUV varies as TSI

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