Solar Science

A blog of solar physics

Posts Tagged ‘Hathaway

David Hathaway: Mea Culpa

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I’m not going to add much more than to say that its enjoyable and refreshing to see a senior scientist admit that they were wholly wrong in their predictions.

How Long Will Our Sun Remain Quiet and Cosmic Rays Increase?

What Happened to 2006 Predictions of Huge Solar Cycle 24?

ISN’T IT ESPECIALLY STRANGE FOR YOU BECAUSE THREE YEARS AGO, ALL THE PHYSICS OF THE SUN THAT YOU AND NASA AND EVERYBODY ELSE WAS USING WERE ANTICIPATING THAT THIS COULD BE THE BIGGEST SOLAR MAXIMUM ON RECORD?

There were indications back then. I am writing a paper – it’s on my computer as we speak (laughs) – basically saying that I made a big mistake – myself and Bob Wilson – when we wrote a paper in 2006, suggesting Solar Cycle 24 was going to be a huge cycle based on conditions at that time. The problem we had with our prediction was that it was based on a method that assumes that we’re near sunspot cycle minimum.

We had just previously gone through three or four sunspot cycles that had been only ten years long each, so for the one in 1996 to 2006, it seemed like a reasonable assumption. But as we now know, we were off by at least two years. And if we take conditions on the sun now, it’s a completely different story. The conditions now – using even that same technique from 2006 – says that the next sunspot cycle is going to be half what we thought it was back in 2006.

Another big prediction in 2006 was based on a dynamo model – a model for how the sun produces magnetic fields – and it suggested a huge cycle.

But there also were people back at that time saying otherwise. A group of colleagues led by Leif Svalgaard, Ph.D., were looking at the sun’s polar fields and saying even at that point, the sun’s polar fields were significantly weaker than they had been before and those scientists back then predicted it was going to be a small cycle.

How Small Will Solar Cycle 24 Be?

…I’ve come around to that view now. I think there is little doubt in my mind now that we’re in for a small cycle. The big question now is how small? I think most of us are predicting small cycles. I think even the techniques I’m using now are suggesting HALF the size of the last three or four solar cycles, but my fear is that even that might be too big just from the fact that it’s taken so long for this Solar Cycle 24 to really get off the ground and start producing sunspots.

I have no doubt at this point that it’s going to be a little cycle. My current prediction is that it’s going to be about half of what we’ve seen in the last four solar cycles or so. But in my gut, I feel it’s going to be smaller than that! (laughs) It’s just so slow in taking off and the indicators that we see – both the polar fields and the geomagnetic indicators are lower than anything we’ve seen before.

So kudos to David Hathaway for writing a paper talking about how wrong his previous papers have been. Absolutely no sarcasm intended or implied.

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Written by John A

October 31, 2009 at 2:58 am

Hathaway announces the bleeding obvious

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NASA’s David Hathaway has announced, again, that Solar Cycle 24 may have begun:

After more than two years of very low sunspot activity and hardly any flares, the sun is ramping up activity now.

The sun’s activity ebbs and flows on a roughly 11-year cycle. It can range from very quiet to violent space storms that knock out power grids on Earth and disrupt radio and satellite communications. The last peak was in 2000, and scientists have in recent months figured the low point was occurring. Fresh sunspots during October suggest the corner has been turned.

“I think solar minimum is behind us,” said David Hathaway of NASA’s Marshall Space Flight Center in Huntsville, Ala. “Last month we counted five sunspot groups.” he says.

Sunspots are cool areas on the solar surface where magnetic energy is bottled up. While five groups is not extraordinary, it is significant in comparison to the months of virtually no spots.

“This represents a real increase in solar activity,” Hathaway said in a statement today.

Your tax money at work. At least he won’t have to keep stretching out the start of SC24 every few months.

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Written by John A

November 13, 2008 at 11:16 am

Posted in Solar Cycle 24

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Predicting the Future ain’t what it used to be

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A quick update on David Hathaway’s predictions for Solar Cycle 24.

Dr Hathaway has changed his prediction once again WITHOUT changing the page that it occurs on (other than the date it was updated), nor with any explanation as to why his previous predictions have been so wrong. It would be nice if he would treat us all to an explanation for modifying his prediction without modifying his methodology.

Here is an animation done by Michael Romayne on how Hathaway’s prediction has changed over time.

Hathaway predictions to OCtober 2008

Its clear that something so flexible as Hathaway’s predictions cannot have a theory behind them – this is just making ad hoc adjustments. Note also that between March 2007 and March 2008, the expected size of SC24 was reduced – why?

h/t to Anthony Watts 

Written by John A

October 6, 2008 at 12:54 pm

Posted in Solar Cycle 24

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Is a New Solar Cycle beginning? Er, no. Not yet.

Much excitement from NASA, as the long delayed arrival of Solar Cycle 24 was announced:

Dec. 14, 2007: The solar physics community is abuzz this week. No, there haven’t been any great eruptions or solar storms. The source of the excitement is a modest knot of magnetism that popped over the sun’s eastern limb on Dec. 11th, pictured below in a pair of images from the orbiting Solar and Heliospheric Observatory (SOHO).

It may not look like much, but “this patch of magnetism could be a sign of the next solar cycle,” says solar physicist David Hathaway of the Marshall Space Flight Center.

Yeees, go on…

“New solar cycles always begin with a high-latitude, reversed polarity sunspot,” explains Hathaway. “Reversed polarity ” means a sunspot with opposite magnetic polarity compared to sunspots from the previous solar cycle. “High-latitude” refers to the sun’s grid of latitude and longitude. Old cycle spots congregate near the sun’s equator. New cycle spots appear higher, around 25 or 30 degrees latitude.

OK, got that. Now we have a sunspot with reversed polarity compared to solar cycle 23?

The region that appeared on Dec. 11th fits both these criteria. It is high latitude (24 degrees N) and magnetically reversed. Just one problem: There is no sunspot. So far the region is just a bright knot of magnetic fields. If, however, these fields coalesce into a dark sunspot, scientists are ready to announce that Solar Cycle 24 has officially begun.

And did this coalesce into a sunspot? No. The Sun remains stubbornly blank although there was a fair sized SC23 spot for several days that followed.There appears to be indications of a large sunspot on the far side of the Sun but that too is right on the equator and probably isn’t polarity reversed from SC23.

This isn’t the first time that a sunspot appeared to herald the next solar cycle that failed to materialize. There was another which appeared in late 2006 that got people excited for literally hours when it appeared and disappeared.

Hathaway, it must be remembered, was one of a team who predicted a very strong SC24, at least as strong as the previous one. I think the tension may be getting to him.

I think its OK to actually wait for at least a couple of magnetically reversed sunspots to appear at high latitudes before announcing the Coming of the next Solar Cycle. Whatever happens, SC24 will be late.

Written by John A

December 22, 2007 at 10:46 am

Posted in Solar Cycle 24

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