Sunspots not an indicator of solar cycle

By Stuart Gary

Underlying solar cycle activity can’t be predicted by sunspot numbers (NASA/TRACE)

A new study of ice core samples has found the link between sunspot activity and the Sun’s solar cycle isn’t as strong as previously thought

Researchers have found the Sun’s eleven-year solar cycle continued normally during the Maunder Minimum between 1645 and 1715, when sunspot activity was unusually low.

This was also a time when northern Europe experienced unusually cold conditions.

The discovery, reported in Geophysical Research Letters, comes as the Sun approaches solarmax, the climax of its cycle, when its north and south magnetic poles flip.

The researchers were looking for solar cycle variations by studying beryllium-10 isotope concentrations in ice core samples.

Showers of heavy isotopes including beryllium-10, are produced when cosmic rays, a high-energy mix of protons, electrons, and atomic nuclei from outside the solar system, collide with molecules in the Earth’s atmosphere.

Increased solar wind activity as the Sun moves towards solar max, reduces the amount of cosmic rays reaching Earth.

Time scales

By studying beryllium-10 levels in ice cores, scientists can determine the level of solar activity at a given time.

Drawing on two independent ice core records, Owens and colleagues modelled solar activity back to 1610, before the Maunder Minimum.

“Between 1650 to 1710 there were no sunspots recorded, even though there were lots of professional astronomers around at the time,” says study lead author Dr Mathew Owens of the University of Reading in the United Kingdom.

“Yet despite the lack of sunspots, the Sun’s magnetic field was still churning over its natural eleven-year solar cycle.”

“It shows sunspots are a symptom not a cause for the solar cycle.”

Read the rest of the article HERE.



3 thoughts on “Sunspots not an indicator of solar cycle

  1. Sean November 26, 2012 / 1:52 pm

    It’s interesting that planetary cooling is better correlated to the length of the solar cycle as opposed to the strength. It is also intesting that Leif considers the Livingston and Penn effect to be the cause of the Maunder minimum but the Dalton was just a cyclic slow down. Leif also noted that the correlation between sunspots and the 10.7 and solar flux is changing. The 10.7 cm solar flux is higher than what you’d expect based on the sunspot count. So given that the 11 (or 22 year) cycle continues even if you do not observe sun spots, it begs the questions, what else is different? Did the length of the underlying cycles change during the period of reduced sunspot activity? No mention is made of this. What is mentioned is that the magnetude changed but there was nothing specific beyond that.
    I think it’s interesting that with the very strong minimu between cycle 23 and 24 there has been some unusual phenomena. We have been in a period of very strong blocking patterns for the last 3 or 4 years with very hot and dry spells intermixed with very cold and snowy spells. NASA also observed the lowest height of the top of the atmoshere back in 2009 andl we’ve had some unusual negative arctic oscillations. Average temperatures may not change much but an very early or late season cold snap or snow storm would be devastating on agriculture. The very low solar wind and changes in solar UV at minimum and in weak cycles (which are much greater than the TSI) seem to be having a pretty profound effect on the upper atmosphere. Perhaps these need to be looked at a lot more carefully.

  2. Russ November 26, 2012 / 3:44 pm

    I agree we have yet to discover the real connection between the climate change here on earth and solar cycles. I would like to see more information on the UV impact. If reader know of some papers on UV we should be posting here, please let us know in the comments.

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