After years of relative somnolence, the sun is beginning to stir. By the time it’s fully awake in about 20 months, the team at NASA’s Goddard Space Flight Center in Greenbelt, Md., charged with researching and tracking solar activity, will have at their dispoal a greatly enhanced forecasting capability.
Goddard’s Space Weather Laboratory recently received support under NASA’s Space Technology Program Game Changing Program to implement “ensemble forecasting,” a computer technique already used by meteorologists to track potential paths and impacts of hurricanes and other severe weather events.
Instead of analyzing one set of solar-storm conditions, as is the case now, Goddard forecasters will be able to simultaneously produce as many as 100 computerized forecasts by calculating multiple possible conditions or, in the parlance of Heliophysicists, parameters. Just as important, they will be able to do this quickly and use the information to provide alerts of space weather storms that could potentially be harmful to astronauts and NASA spacecraft.
“Space weather alerts are available now, but we want to make them better,” said Michael Hesse, chief of Goddard’s Space Weather Laboratory and the recently named director of the Center’s Heliophysics Science Division. “Ensemble forecasting will provide a distribution of arrival times, which will improve the reliability of forecasts. This is important. Society is relying more so than ever on space. Communications, navigation, electrical-power generation, all are all susceptible to space weather.” Once it’s implemented, “there will be nothing like this in the world. No one has done ensemble forecasting for space weather.”
The state-of-the-art capability, which Hesse’s group is implementing now and expects to complete within three years, couldn’t come too soon, either.
Sun Growing Restless
Since the sun reached its solar minimum in 2008 — the period when the number of sunspots is lowest — it has begun to awaken from its slumber. On Aug. 4, the sun unleashed a near X-class solar flare that erupted near an Earth-facing sunspot. Although flares don’t always produce coronal mass ejections (CMEs) — gigantic bubbles of charged particles that can carry up to ten billion tons of matter and accelerate to several million miles per hour as they erupt from the sun’s atmosphere and stream through interplanetary space — this one did.
The CME overtook two previous CMEs — all occurring within 48 hours — and combined into a triple threat. Luckily for Earthlings, the CMEs produced only a moderate geomagnetic storm when solar particles streamed down the field lines toward Earth’s poles and collided with atoms of nitrogen and oxygen in the atmosphere. Even so, “it was the strongest storm in many years,” said Antti Pulkkinen, one of the laboratory’s chief forecasters.
However, the repercussions could be far worse in the future. As part of its 11-year cycle, the sun is entering solar maximum, the period of greatest activity. It is expected to peak in 2013. During this time, more powerful CMEs, often associated with M- and X-class flare events, become more numerous and can affect any planet or spacecraft in its path. In the past, solar storms have disrupted power grids on Earth and damaged instrumentation on satellites. They can also be harmful to astronauts if they are not warned to take protective cover.
“No one knows exactly what the sun will do, Pulkkinen said. “We can’t even tell in a week, let alone a year or two, what the sun will do. All we know is that the sun will be more active.” …
Good luck, planet Earth.