Why there is no evidence for a new Maunder Minimum
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Why there is no evidence for a new Maunder Minimum

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Douglas Biesecker, a scientist at the Space Weather Prediction Center of the National Oceanic and Atmospheric Administration, prepared this Powerpoint presentation to summarize his concerns about new ...

Douglas Biesecker, a scientist at the Space Weather Prediction Center of the National Oceanic and Atmospheric Administration, prepared this Powerpoint presentation to summarize his concerns about new predictions of a deep, protracted lull in solar activity. “I consider the strength of evidence to be anemic and the reasoning to be highly suspect,” he told me for a post on Dot Earth:
Would Solar Lull Snuff Climate Action? - http://nyti.ms/il0Wqj

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    Why there is no evidence for a new Maunder Minimum Why there is no evidence for a new Maunder Minimum Presentation Transcript

    • Why there is no evidence for a new Maunder Minimum Doug Biesecker
    • Appearance of Jet Streams aka Torsional Oscillations Solar Min Start of Poleward Branch Solar Min Weak and patchy
    • Comments on ‘jet stream’
      • Press release says expected to form by 2008.
        • Formation of pole-ward jet last cycle started ~8 months after solar minimum.
        • Poleward jet was weak and patchy at start of last cycle for anywhere from 18-30 months
        • The recent solar minimum wasn’t until December, 2008, so assuming the same delay as last cycle, we wouldn’t expect it before mid-2009.
          • Don’t I see a hint of something at almost the exact same delay?
          • This cycle is weaker than the last, so why not expect a weaker signal than last time?
          • We only have a 1-cycle history. What makes us think that one cycle is normal? There is no way of knowing what the natural variability is.
    • The slowing ‘rush to the poles’ Cycle 21 (10.3 yrs) Cycle 22 (10.0 yrs) Cycle 23 (12.2 yrs)
    • Comments on ‘rush to the poles’
      • Press release says Cycle 24 started out late and has a slow rush to the poles
        • Yes, cycle 24 started ‘late.’ Cycle 23 was 12 years long, 2 years longer than the previous two cycles. However, I see the iron emission appearing right as expected, 12 years after the last one
        • Why is the cycle 24 rush to the poles drawn to include a segment of the equatorward branch.
          • There is no physical reason to connect both
          • This results in a misleading slope
    • Weakening Magnetic Fields in Sunspots
      • What was in the press release
      • The raw data presented at Space Weather Workshop 2010
      Solar Max Solar Min
    • Comments on weakening magnetic field in sunspots
      • Press release says that >13 years of data show 50 Gauss per year drop in magnetic field
        • The figure used in the press release, available at http://www.boulder.swri.edu/~deforest/SPD-sunspot-release/ is somewhat misleading (I know, it does have error bars), but the reality is the data before and at solar max is incredibly sparse.
        • There is no obvious reason that a straight line is the appropriate fit to these data. A curve that follows the solar cycle may in fact provide a better reduced chi square.
          • That is, an increase in the magnetic field strength before solar maximum and also an increase after solar minimum looks completely consistent with the data