Solar Science

A blog of solar physics

Failed Predictions of Solar Cycle 24 – #1 Dikpati and Hathaway 2006

with 8 comments

Looking back into the archives, there are many many predictions of the start and size of solar cycle 24 given on the highest possible scientific authority that turned out to be flat out wrong.

Here’s one

March 10, 2006: It’s official: Solar minimum has arrived. Sunspots have all but vanished. Solar flares are nonexistent. The sun is utterly quiet.

Like the quiet before a storm.

This week researchers announced that a storm is coming–the most intense solar maximum in fifty years. The prediction comes from a team led by Mausumi Dikpati of the National Center for Atmospheric Research (NCAR). “The next sunspot cycle will be 30% to 50% stronger than the previous one,” she says. If correct, the years ahead could produce a burst of solar activity second only to the historic Solar Max of 1958.

This is important. The solar minimum began around March 2006 and today August 30, 2009 the Sun is still in that minimum with no sign of it ending.

The failed predictor: The Solar Conveyor Belt Theory

Dikpati’s prediction is unprecedented. In nearly-two centuries since the 11-year sunspot cycle was discovered, scientists have struggled to predict the size of future maxima—and failed. Solar maxima can be intense, as in 1958, or barely detectable, as in 1805, obeying no obvious pattern.

The key to the mystery, Dikpati realized years ago, is a conveyor belt on the sun.

I try to remove some of the waffle here because the article talks about the Earth’s ocean conveyor belt as an analogue but frankly its not relevant, nor useful.

The sun’s conveyor belt is a current, not of water, but of electrically-conducting gas. It flows in a loop from the sun’s equator to the poles and back again. Just as the Great Ocean Conveyor Belt controls weather on Earth, this solar conveyor belt controls weather on the sun. Specifically, it controls the sunspot cycle.

Solar physicist David Hathaway of the National Space Science & Technology Center (NSSTC) explains: “First, remember what sunspots are–tangled knots of magnetism generated by the sun’s inner dynamo. A typical sunspot exists for just a few weeks. Then it decays, leaving behind a ‘corpse’ of weak magnetic fields.”

Enter the conveyor belt.

The Solar Conveyor belt according to NASA

The Solar Conveyor belt according to NASA

“The top of the conveyor belt skims the surface of the sun, sweeping up the magnetic fields of old, dead sunspots. The ‘corpses’ are dragged down at the poles to a depth of 200,000 km where the sun’s magnetic dynamo can amplify them. Once the corpses (magnetic knots) are reincarnated (amplified), they become buoyant and float back to the surface.” Presto—new sunspots!

Presto! No, it didn’t this time. This time the belt moved to the critical latitude of 22 degrees and we got a single sunspot and that’s it.

All this happens with massive slowness. “It takes about 40 years for the belt to complete one loop,” says Hathaway. The speed varies “anywhere from a 50-year pace (slow) to a 30-year pace (fast).”

When the belt is turning “fast,” it means that lots of magnetic fields are being swept up, and that a future sunspot cycle is going to be intense. This is a basis for forecasting: “The belt was turning fast in 1986-1996,” says Hathaway. “Old magnetic fields swept up then should re-appear as big sunspots in 2010-2011.”

There’s the prediction from 2006. We’ve yet to reach 2010 but Hathaway was talking about 2010-2011 as the time of the SC24 maximum when we haven’t yet reached the end of the minimum in August 2009.

Here’s where the claim of scientific authority is made. This isn’t just any old joe making a prediction, this is expertise:

Like most experts in the field, Hathaway has confidence in the conveyor belt model and agrees with Dikpati that the next solar maximum should be a doozy. But he disagrees with one point. Dikpati’s forecast puts Solar Max at 2012. Hathaway believes it will arrive sooner, in 2010 or 2011.

“History shows that big sunspot cycles ‘ramp up’ faster than small ones,” he says. “I expect to see the first sunspots of the next cycle appear in late 2006 or 2007—and Solar Max to be underway by 2010 or 2011.”

Wrong. An expert strikes out.

Who’s right? Time will tell. Either way, a storm is coming.

It turns out that neither was right. The extended solar minimum caught some of NASA’s brightest experts with their predictive pants down.

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Written by John A

August 29, 2009 at 1:28 pm

8 Responses

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  1. Can academics really spin theories as ludicrous as this “conveyor belt” one? The corpses of magnetic fields being recycled 200,000 km into the Sun? How would structure retain their coherence down there? For that matter, how would they retain their coherence on the surface? It is (blindingly) obvious that sunspots are secondary effects of surface phenomena, and do not have existences of their own.

    I know there’s a lot of junk science out there, but it may be worse than I thought.

    William Walker

    August 29, 2009 at 8:35 pm

  2. I’d agree completely, the ‘conveyor’ model seems dead and recycling of toroids, buried.

    gary gulrud

    August 31, 2009 at 3:14 am

  3. Even the idea of Earth’s ocean conveyor belt concept was recently exposed as incorrect as well. So no wonder they were wrong. Hence the earth analogy to the sun is absolutely relevant, the common element was an exuberant self assured belief system based on computer models supported by a lack of facts. Hmmm, sounds like another popular scientific theory…


    August 31, 2009 at 4:36 am

  4. @William Walker
    I don’t think of it as junk science – its just that empirical evidence has a nasty habit of sinking fashionable ideas, and this is one of them.

    It means there’s more to learn about the sun than previously thought. That is a good thing.

    John A

    August 31, 2009 at 7:26 pm

  5. @John A
    It’s junk science because the idea of magnetic corpses being sucked into the Sun and revived, is totally contrary to physical law. This is not a question of learning about the sun, but of correctly applying physical law which is well-understood to undergraduates. The whole concept is ludicrous, and that’s why it is junk science. Or just junk.

    William Walker

    September 1, 2009 at 6:20 pm

  6. @William Walker
    I can think of it as plausible and debunked by reality. That’s the normal scientific process.

    Remember that the Wegener’s hypothesis of continental drift was derided as a junk, crackpot theory with no physical basis until the 1950s.

    I can agree that some theories now being proclaimed are based on non-physical principles – like the notion of a “global mean temperature”, or that the Earth’s atmosphere “must be in radiative balance” at any time.

    John A

    September 2, 2009 at 10:46 am

  7. […] This post was Twitted by abrancoalmeida […]

    Twitted by abrancoalmeida

    September 5, 2009 at 10:41 pm

  8. Has anyone published a series on Hathaway’s proposed graphs of sun spot activity? Somehow the mean and 95% confidence intervals seem to be actively moving into the future.


    September 11, 2009 at 1:14 am

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