For the first time, scientists have used artificial intelligence not only to predict sunspots but also to correct the incomplete record of past sunspot activity.
A new paper just published in Advances in Space Research by Dr Victor Velasco Herrera, a theoretical physicist at the National Autonomous University of Mexico, Dr Willie Soon, an award-winning solar astrophysicist at the Harvard-Smithsonian Center for Astrophysics, and Professor David Legates, a climatologist at the University of Delaware and former director of the U.S. Global Change Research Program, predicts that the new 11-year solar cycle that has recently begun will show near-record low sunspot activity that will last until mid-century.
Both Dr Soon (in 2004) and Dr Velasco Herrera (in 2008) had previously published papers speculating that the first half of the 21st century would be a period of unusually few sunspots, potentially slowing the rate of global warming
Sunspots matter. When there are many sunspots and the Sun is active, there is a danger that a strong solar ejection directed towards the Earth could damage or even destroy the thousands of satellites on which the world depends for everything from radio, telephone, television and internet communications to monitoring the climate and observing the farthest reaches of the universe.
Worse, a really strong solar storm could damage the largely unshielded terrestrial electricity grid. Most power lines and transformers are above ground and thus acutely vulnerable. Solar panels, too, could have their lives shortened by intense solar radiation.
The three scientists taught a machine-learning algorithm how to recognize underlying patterns and cycles in the past 320 years’ sunspot record. The algorithm then discovered a hitherto-unnoticed interaction between the 5.5-year solar half-cycles (blue) and the 120-year Gleissberg double cycles (red dotted lines) which allowed it to confirm the earlier predictions of a quiet half-century to come – predictions which are now shared by solar physicists.
That interaction between the two periodicities led the algorithm to indicate that from the 1730s to the 1760s, early in the modern sunspot record (the gray band below), sunspots appear to have been under-recorded: as the 120-year cycle approached its maximum amplitude, sunspots should have been more numerous than reported at the time.
The algorithm then predicted the sunspots from 2021 to 2100. It suggests that the current low solar activity is likely to continue until 2050:
Dr Velasco Herrera said: “Not everyone agrees with our expectation that solar activity will continue to be low for another three solar cycles. A paper in Solar Physics by Dr Scott McIntosh of the U.S. National Center for Atmospheric Research, says the coming solar cycle will be unusually active, with a peak sunspot number of 233, compared with our estimate of less than 100. Place your bets in the Battle of the Solar Cycles!”
Dr Soon said, “The machine-learning algorithm, with its interesting interplay between the very short 5.5-year cycle and the long 120-year cycle, confirms our results of 10-15 years ago suggesting that the next three or four solar cycles will be comparatively inactive. This is the first time that the twin problems of hindcasting incomplete past records and forecasting the future have been combined in a single analysis.”
Dr Legates said: “President Trump realized the importance of space weather, and particularly of the Sun, in influencing global climate. It was he who signed the October 2020 ProSwift Act into law to assist in studying and forecasting space weather. Given the history of previous periods of comparative solar activity, the weather may get a little cooler between now and 2050. If we are right, our electricity grids and our satellites should be safe until then.”
Interested readers may download the paper for free from the journal before June 6