PDA

View Full Version : Scientists are Starting to Understand Solar Cycles



Blob
2006-Mar-06, 07:01 PM
The next sunspot cycle will be 30 to 50 percent stronger than the last one, and begin as much as a year late, according to a breakthrough forecast using a computer model of solar dynamics developed by scientists at the National Centre for Atmospheric Research (NCAR) in Boulder, Colorado, US. The research results, funded by the National Science Foundation (NSF) and NASA, were published on-line on March 3 in the American Geophysical Union journal Geophysical Research Letters.

Scientists now predict that the next cycle, known as Cycle 24, will produce sunspots across an area slightly larger than 2.5 percent of the visible surface of the Sun. The cycle is projected to reach its peak about 2012, one-year later than indicated by alternative forecasting methods that rely on statistics.
By analysing recent solar cycles, the scientists also hope to forecast sunspot activity two solar cycles, or 22 years, into the future. The team is planning in the next year to issue a forecast of Cycle 25, which will peak in the early 2020s.

Read more (http://www.nsf.gov/news/news_summ.jsp?cntn_id=105844&org=NSF&from=news)

antoniseb
2006-Mar-06, 08:01 PM
Interesting. Are they using methods other than neural net analysis of patterns over previous cycles? I wonder how they are coming to this prediction. Is there a paper around explaining more?

Swift
2006-Mar-06, 08:54 PM
Very neat

The cycle is projected to reach its peak about 2012, one-year later than indicated by alternative forecasting methods that rely on statistics.

my bold
I also predict that the woo-woo output will reach a new high too.
Those Mayan Solar Physicsts were so smart. :shifty:

Blob
2006-Mar-06, 09:02 PM
Hum,
i can only point out their link:

Predicting the strength of solar cycle 24 using a flux-transport dynamo-based tool
Author: Peter A. Gilman

Abstract:
We construct a solar cycle strength prediction tool by modifying a calibrated flux-transport dynamo model, and make predictions of the amplitude of upcoming solar cycle 24. We predict that cycle 24 will have a 3050% higher peak than cycle 23, in contrast to recent predictions by Svalgaard et al. and Schatten, who used a precursor method to forecast that cycle 24 will be considerably smaller than 23. The skill of our approach is supported by the flux transport dynamo model's ability to correctly 'forecast' the relative peaks of cycles 1623 using sunspot area data from previous cycles.

http://www.agu.org/pubs/crossref/2006/2005GL025221.shtml

Fraser
2006-Mar-07, 04:44 AM
SUMMARY: Solar scientists think they're finally getting a handle on predicting the Sun's cycles. If everything goes as they predict, the next solar cycle will be 30-50% stronger, and be up to a year late. Astronomers have been tracking the two major flows of plasma that goven the Sun's cycles. One acts like a conveyor belt, pulling plasma from the poles to the equator, and the other gets stretched since the Sun rotates faster at the equator than at the poles. This causes the Sun's magnetic field to concentrate, creating the solar maximum.

View full article (http://www.universetoday.com/am/publish/30_50_solar_cycle.html)
What do you think about this story? post your comments below.

AKONI
2006-Mar-07, 12:25 PM
Since the news sometimes gets the facts wrong, what's your take on this?


http://today.reuters.com/news/articlenews.aspx?type=scienceNews&storyid=2006-03-06T204858Z_01_N06327000_RTRUKOC_0_US-SPACE-SUN.xml&rpc=22

Tog
2006-Mar-07, 12:51 PM
My understanding, which may be wrong, was that the cycle was 22 years peak to peak. 11 from min to max, and the last max was in 2003 or so. If I'm remebering this correctly, then it would seem that most of that article is wrong.

Okay... I missed the year Wiki (http://en.wikipedia.org/wiki/Solar_maximum)

dgruss23
2006-Mar-07, 01:23 PM
My understanding, which may be wrong, was that the cycle was 22 years peak to peak. 11 from min to max, and the last max was in 2003 or so. If I'm remebering this correctly, then it would seem that most of that article is wrong.


The Solar cycle is 11 years in length from maximum to maximum. There is a 22 year magnetic activity cycle. In that cycle if the northern hemisphere of the Sun has North magnetic polarity in the first 11 year cycle and then it will have south magnetic polarity in the next cycle. But in either case it is ~5 1/2 years between min and max.

antoniseb
2006-Mar-07, 02:01 PM
Wow! That is really impressive. I hope that this prediction proves accurate enough to merit future probes even more sophisticated than the Solar Dynamics Observatory mentioned in the article. This is getting to a whole new level of sophistication in understanding the Sun.

ToSeek
2006-Mar-07, 04:23 PM
Threads on same topic merged and retitled - may be some slight confusion, but I thought both discussions should be in the same place.

jkmccrann
2006-Mar-07, 04:56 PM
Well, just hope the satellites are up to it. Sure they will be though, nothing much happened last time round did it?

Blob
2006-Mar-07, 05:41 PM
Hum,

“The NCAR team's computer model, known as the Predictive Flux-transport Dynamo Model, draws on research by NCAR scientists indicating that the evolution of sunspots is caused by a current of plasma, or electrified gas, that circulates between the Sun's equator and its poles over a period of 17 to 22 years. This current acts like a conveyor belt of sunspots....The subsurface plasma flow used in the model has been verified with the relatively new technique of helioseismology, based on observations from both NSF– and NASA–supported instruments. This technique tracks sound waves reverberating inside the Sun to reveal details about the interior, much as a doctor might use an ultrasound to see inside a patient.”

And judging from the graph at their website their simulations do seem to be quite accurate...

http://www.ucar.edu/news/releases/2006/sunspot.shtml

BTW, the solar cycle is not precisely 11 years long. Its length, measured from minimum to minimum, varies: The shortest cycles are 9 years, and the longest ones are about 14 years. Researchers aren't sure exactly what makes a cycle long or short . And i believe that there is a longer 72 year cycle involved as well...

ToSeek
2006-Mar-07, 07:24 PM
One side effect could be that satellites re-enter sooner: the Sun at its maximum heats up the atmosphere more, so that it expands to a higher altitude and slows down orbiting satellites more. This could be a real issue for missions like Hubble.

Blob
2006-Mar-07, 10:36 PM
Indeed,
There is also the possibility of communication disturbance and power cuts, and the downfall of the western civilisation - though it is balanced up by the glorious Aurora that will be seen...

Duane
2006-Mar-08, 09:09 AM
I have merged two discussions, as they are about the same topic.

Hermes
2006-Mar-10, 02:20 AM
How does this model account for the maunder minimum?

antoniseb
2006-Mar-10, 02:42 AM
How does this model account for the maunder minimum?
Whoever said it did? I get the impression that this is like weather forecasting, and we have only seen it for a small period of time. We will probably hve a very good idea about how this works with the events like the Maunder minimum before the next time there is one.

bigboy
2006-May-04, 04:16 PM
Until about 30 years ago, solar cycle prediction (before the actual onset of the new cycle) was more an art than science, as solely based on statistics (mostly Wolfnumbers). Once the new cycle was underway, its amplitude was better predictable. E.g. Waldmeier's law predicts a short time of rise to maximum points to a strong maximum, and vice versa. The average time of rise is about 4 years, and it takes another 7 years to get back down to the next minimum. As no two solar cycles are alike, amplitudes change, thus also their length. Since the 1920's, the solar cycle length is rather about 10,5 years, in stead of the average of 11 years. Also, in the last 50 years the sun produced the 3 strongest cycles in over 250 years of monitoring. Longer cycles are not excluded: E.g. the Gleissberg cycle should have a period of 80 to 90 years, but it's based on fuzzy statistics and there certainly is no physical explanation for it yet. If Gleissberg holds up, we should now be around a period of minimum activity (low cycle amplitude), and the moderate amplitude of last cycle (23rd) might be a sign of even lower amplitude cycles to come.

The importance of correct and in advance solar cycle prediction has grown with the increasing use of satellites. High solar activity means more solar storms, which can short circuit satellite's solar panels or electronics, change bits (imagine what that does to your GPS!), or -temporarily- disable pointing devices (SOHO!). As also has been mentioned in this thread, those energetic particles tend to swell earth's atmosphere, increasing friction with the satellite which in turn will fall back to earth more quickly (e.g. Solar Max). Putting satellites higher above the atmosphere requires more fuel, hence will cost more money which companies are only willing to pay if really necessary (i.e. if there sound predictions/indications for it).

The technique announced in the article is new and based on physical data. This is bad and good news. Good because of the physics implied, and that's -in my opinion- the only way to get a firm(er) hold on solar cycle prediction (and ultimately on deviations like Gleissberg and Maunderminimum). The bad news is that it is a new technique, meaning that it still has to prove itself. I'm not impressed by the good forecasting this method does of ***previous*** solar cycles. Only 10 years ago, geomagnetic precursor methods were hyped for the same reason, but the predicted high amplitude 23rd solar cycle was flat wrong. Also, the method's result is in conflict with other physical methods who did do a good job in predicting the amplitude of the last 2 solar cycles (Schatten).

More on the Sun and solar activity can be found at my website
( http://members.chello.be/j.janssens/Engwelcome.html )

ToSeek
2006-Aug-16, 06:03 PM
Backward Sunspot (http://science.nasa.gov/headlines/y2006/15aug_backwards.htm)


On July 31st, a tiny sunspot was born. It popped up from the sun's interior, floated around a bit, and vanished again in a few hours. On the sun this sort of thing happens all the time and, ordinarily, it wouldn't be worth mentioning. But this sunspot was special: It was backward.

see caption"We've been waiting for this," says David Hathaway, a solar physicist at the Marshall Space Flight in Huntsville, Alabama. "A backward sunspot is a sign that the next solar cycle is beginning."

"Backward" means magnetically backward.