Solar Science

A blog of solar physics

Solar Cycle 24: False Starts

with 9 comments

In early January 2008, NASA reported the start of Solar Cycle 24 with the sighting of a tiny reversed polarity spot. It lasted three days and then disappeared.

This was reported by Anthony Watts thus:

Solar physicists have been waiting for the appearance of a reversed-polarity sunspot to signal the start of the next solar cycle. The signal for the start of a new cycle is sighting a particular kind of sunspot. That wait is over.

And the NASA blog said:

“On January 4, 2008, a reversed-polarity sunspot appeared—and this signals the start of Solar Cycle 24,” says David Hathaway of the Marshall Space Flight Center.

Above: Images of the first sunspot of Solar Cycle 24 taken by the NASA/ESA Solar and Heliospheric Observatory (SOHO).

Solar activity waxes and wanes in 11-year cycles. Lately, we’ve been experiencing the low ebb, “very few flares, sunspots, or activity of any kind,” says Hathaway. “Solar minimum is upon us.”

But the first announcement of Solar Cycle 24 wasn’t made by NASA in January 2008 – it was actually made by Ulrich Reith on 31 July 2006, with this post:

Last night it seems to have happend, the first sunspot of solar cycle 24 appeard on the southern hemisphere of the sun.
Very close to NOAA 10902 a tiny spot which should be named 10903 appeared at S12W55.
In the SOHO MDI magnetogramms it clearly shows a reversed polarity if compared to the polarity of cycle 23. (cycle 23: black first towards the western limb and white following black / cycle 24: white in front of black)

And I show the picture with an arrow so you know which spot we’re talking about.
ulrichreith-sc24spot-31072006arrow.GIF

Again, the spot persisted for a few days and disappeared.

So what to believe? The transition between one solar cycle and the next is very difficult to call as during the transition both magnetically polarized spots can be seen. The newer cycle spots are usually high latitude (>20o) North and South of the solar equator. Solar cycle 23 spots still continue to produce and any SC24 spots so far are barely a pixel in size and very rare.

Solar cycle 24 remains difficult to call definitively at this time, in my view.

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Written by John A

February 4, 2008 at 4:37 am

9 Responses

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  1. Don’t forget all the SC23 Coronal Holes, they are supposed to mostly or completely disappear before SC24 can begin. Currently they do not appear to be waning with any particular urgency.

    Jack

    February 4, 2008 at 3:18 pm

  2. I made some comments early January on the appearance of the new cycle spot -and all the hype about it- in this document: http://users.telenet.be/j.janssens/SC24_start_strength.pdf

    Kind regards,

    J. Janssens

    February 4, 2008 at 7:10 pm

  3. Great post and comments! Today Alvestad’s site shows three coronal holes distributed either side of the equator. Looks like the AGW folks had better arrange for retirement.

    Gary Gulrud

    February 5, 2008 at 7:22 pm

  4. I don’t know about the AGW folks yet, but Hathaway is going to have to redo his forecasting if this keeps up. Leif Svalgaard’s prediction of June on the other hand is getting more accurate by the day. LOL

    The late start of 24 is going to answer a lot of questions in regard to solar prediction theories but then it may raise other questions. As to the AGW folks, well, if the cycle doesn’t start to June and it’s a cooler than normal summer you may have people questioning that theory as well but we all know correlation is not causation.

    dscott

    February 5, 2008 at 8:48 pm

  5. If that sunspot in late July 2006 was for real and got a number, then SC24 is really 18 months old.

    Ironically, the consensus for group minimum is March 2008, which is 19 months into SC24 if you count the July sunspot. This is within the range of 12 to 20 months from first sunspot of new cycle to cycle minimum.

    If there is no consistent and clear way to determine the beginning of a new SC, then the scientists ought to invent a new method, such as discarding the first x number of sunspot groups with reversed polarity. This is similar to what Leif suggested (at climate audit) for reducing noise in the charts for the evolution of spotless days after cycle maximum. It sounds reasonable to me.

    I guess that I don’t see how you can just discard data if it doesn’t happen to fit the prevailing model. We’re not talking tree rings here.

    Was that July sunspot really given an official number?

    Harold Vance

    February 9, 2008 at 9:11 pm

  6. Harold,

    In the document linked in my comment #2 I answered some of your questions.

    The July 2006 group was not numbered by NOAA. It was also at only -13°, which is still really in the “confusion” zone whether the group is really a SC24-group, or just a group from the northern hemisphere that has wandered too far south.

    The minimum of a cycle is very clearly determined as the minimum of the 13-month smoothed average of the sunspotnumber (SIDC-formula). As long as this value is not reached, the cycle has not begun. The appearance of the first sunspotgroup with the new magnetic polarity is just the first sign that the cycle is about to begin.

    You may find some info and charts on spotless days at my website http://users.telenet.be/j.janssens/Spotless/Spotless.html . My feeling is there are still many spotless days ahead.

    Kind regards,

    J. Janssens

    February 9, 2008 at 10:02 pm

  7. J. Janssens:

    I just find myself wondering as to why a single, very small polarity reversed spot in 2008 is the start of SC24 when a similar spot in 2006 is not.

    Or perhaps neither of them are.

    I wonder if the solar cycle really has begun.

    I also wonder since we appear to have a very strong La Nina in the Pacific, a flipping over to the cold version of the PDO, and a prolonged solar minimum, whether we should be worried about global cooling.

    John A

    February 11, 2008 at 12:01 pm

  8. The reason they say it isnt is that the reverse polarity sunspot needs to be of a high latitude and not a low latitude – that is why it was disregarded.

    Doug

    February 21, 2008 at 12:22 pm

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