Researchers with the National Center for Atmospheric Research (NCAR) have identified a previously undetected cycle of ‘weather’ patterns on the Sun which could help in predicting solar events. Geomagnetic storms from the Sun can disrupt power grids, satellites and communication networks, being able to predict such events won’t necessarily prevent damage but could allow officials to prepare for it.
According to a study published this week in Nature Communications the cycle is driven by changes in magnetic fields in the Sun’s northern and southern hemispheres. These cycles which wax and wane every two years and help shape the 11 and 22 year cycles identified in a paper by the same authors in Astrophysical Journal.
“What we’re looking at here is a massive driver of solar storms. By better understanding how these activity bands form in the Sun and cause seasonal instabilities, there’s the potential to greatly improve forecasts of space weather events,” said Scott McIntosh, lead author of the new study and director of NCAR’s High Altitude Observatory in a statement.
Using a variety of NASA satellite and ground based data, the team identified migrating magnetic bands which produced predictable variations in solar activity. These variations were found to take place separately in each of the Sun’s hemispheres.
“Much like Earth’s jet stream, whose warps and waves have had severe impact on our regional weather patterns in the past couple of winters, the bands on the Sun have very slow-moving waves that can expand and warp it too. Sometimes this results in magnetic fields leaking from one band to the other. In other cases, the warp drags magnetic fields from deep in the solar interior, near the tachocline, and pushes them toward the surface,” said co-author Robert Leamon, a scientist at Montana State University.
The researchers found that the quasi-annual events destabilize the Sun’s outermost atmosphere and appear to be the driving force behind severe solar storms.
“These surges or ‘whomps’ as we have dubbed them, are responsible for over 95 percent of the large flares and CMEs—the ones that are really devastating,” McIntosh said.
The authors believe that the finding also solves the Gnevyshev Gap. First noticed in the 1940s it refers to the puzzle of a spike in powerful solar flares and coronal mass ejections (CMEs) following a year in which there was a spike in sunspots.
The findings should lead to more advanced simulations and models for solar weather prediction.
“If you understand what the patterns of solar activity are telling you, you’ll know whether we’re in the stormy phase or the quiet phase in each hemisphere. If we can combine these pieces of information, forecast skill goes through the roof,” said McIntosh.
In addition to the discoveries by McIntosh and his fellow researchers, the NOAA launched the Deep Space Climate Observatory (DSCOVR) early this year. Once it is in place and fully operational, the satellite is expected to provide the best information to date about solar weather.
In addition to predicting future weather and preparing Earth’s satellite and communication systems, all of this information will be important in planning future deep space missions. A manned trip to Mars, for example, could take six to nine months each way and preparations will have to be made for the possibility of solar activity.
