Feb 3, 2000

Solar Cycle Update

SOHO image of the sun on January 16, 2000
February 4, 2000 -- Scientists have been watching and charting the Sun’s explosive activity since Galileo developed the telescope in the early 1600s. But while they have been able to follow the 11-year sunspot cycle -- expected to crest in mid-2000 -- scientists have had little success predicting the variation in sunspot number from month to month. Sunspots are the precursors to solar flares and other space weather events.

"If you look at it from day to day, the Sun’s activity fluctuates wildly," says Dr. David Hathaway, leader of the Marshall Space Flight Center's solar physics group. "If you look at the monthly values, they fluctuate wildly, as well."

Above: This image of the Sun recorded by the Solar and Heliospheric Observatory on January 16, 2000, shows many sunspots. The sunspot number is increasing as we head toward solar maximum in mid-2000.

Using a new forecasting technique, Hathaway predicts "this cycle looks like it’s going to be bigger than average."

Prior to the Space Age, the most visible effect of solar activity was the showy aurora borealis, or Northern Lights, Hathaway said. "Because we’re more dependent on technology now -- in particular as we venture into space - it’s more important for us to understand solar activity and predict it reliably so people can take the necessary precautions."

For instance, during the solar maximum of 1989, such a "solar power surge" damaged transformers of the Hydro-Quebec power system, leaving 6 million people in Canada and the Northeast United States powerless for more than nine hours.

Scientists have worked for decades with dozens of prediction techniques, focusing on two methods to forecast sunspots: long-term predictions for the size of the next cycle and month-to-month forecasts within a given cycle. At best, their results have been mediocre. The long-term predictions, called precursor methods, only forecast a cycle’s general intensity. And the month-to-month forecasts were accurate only in the middle of a cycle.

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Above: By combining data about geomagnetic activity during the previous solar cycle with sunspot counts for the current cycle, David Hathaway and collaborators are able to predict when the next sunspot maximum will occur. [Click here for details]. According to their results, the sunspot number -- and other forms of solar activity -- will peak beginning in mid-2000. The dotted lines above and below the solid curve line indicate the prediction curve's range of error.

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Hathaway analyzed scores of techniques, combining the best of several. He took two precursor methods that generally scored much better than others and usually had offsetting errors, and combined them into a weighted value. These values were then used with a bell curve of monthly sunspot activity. When he aligned the low points of the curve with low points of the current solar activity cycle, he found the results were better than expected.

"Three out of the last four months have been right on what we have predicted," he said.

Hathaway predicts solar max 2000 will reach its peak in mid to late 2000, but high levels of activity will continue well into 2001. "The sunspot maximum is usually a broad peak," he said. "There is a two- or three-year period when activity is quite high." Still, he said, solar max 2000 will be "no record-breaker."Web Links

Solar Smoke Rings - a series of coronal mass ejections dazzle scientists.

Solar Cinema - Cool movies of a recent solar prominence. -follow the latest events on the Sun

Coronal Mass Ejections -from the Marshall Space Flight Center

SOHO home page -real-time images, screen savers, and more