Everyone is familiar with weather systems on Earth like rain, wind and snow. But space weather – variable conditions in the space surrounding Earth – has important consequences for our lives inside Earth’s atmosphere.
Solar activity occurring miles outside Earth’s atmosphere, for example, can trigger magnetic storms on Earth. These storms are visually stunning, but they can set our modern infrastructure spinning.
On Jan. 19, scientists saw a solar flare in an active region of the Sun, along with a concentrated blast of solar-wind plasma and magnetic field lines known as a coronal mass ejection that burst from the Sun’s surface and appeared to be headed for Earth. When these solar winds met Earth’s magnetic field, the interaction created one of the largest magnetic storms on Earth recorded in the past few years. The storm peaked on Jan. 24, just as another storm began.
“These new storms, and the storm we witnessed on Sept 26, 2011, indicate the up-tick in activity coming with the Earth’s ascent into the next solar maximum,” said USGS geophysicist Jeffrey Love.” This solar maximum is the period of greatest activity in the solar cycle of the Sun, and it is predicted to occur sometime in 2013, which will increase the amount of magnetic storms on Earth.
Magnetic storms, said Love, are a space weather phenomenon responsible for the breathtaking lights of the aurora borealis, but also sometimes for the disruption of technology and infrastructure our modern society depends on. Large magnetic storms, for example, can interrupt radio communication, interfere with global-positioning systems, disrupt oil and gas well drilling, damage satellites and affect their operations, and even cause electrical blackouts by inducing voltage surges in electric power grids.
Storms can also affects airline activity — as a result of last weekend’s storm, both Air Canada and Delta Air Lines rerouted flights over the Arctic bound for Asia as a precautionary measure. Although the storm began on the 19th of January, it did not peak until January 24th.
STORM RECAP: As expected, a CME hit Earth’s magnetic field on Jan. 24th at approximately 1500 UT (10 am EST). The impact produced a G1-class geomagnetic storm and bright auroras around the Arctic Circle.
Even veteran aurora watchers were impressed. “This was one of the best displays that I’ve ever seen, and I mean ever in over 5000 hours on the ice,” says Andy Keen of Finland. “It was, in short, truly spectacular and something that will live with me for a lifetime.” In the Abisko National Park of Sweden, aurora tour guide Chad Blakely contributed a similar report: “Eight tourists and I were treated to one of the most wonderful displays I have ever seen. The auroras began as we were eating dinner and continued into the very early hours of the morning. Words can not describe the excitement we shared.”
SUBSIDING STORM: A geomagnetic storm caused by Monday’s M9-class solar flare and Tuesday’s CME impact is over. The aurora watch is cancelled for all but the higher latitudes around the Arctic Circle.
The geomagnetic field was quiet to major storm on January 24.
Solar wind speed ranged between 347 and 732 km/s. A strong solar wind shock was observed at SOHO at 14:34 UTC, the arrival of the CMEs observed early on January 23. The geomagnetic disturbance peaked 17-20h UTC when the planetary A index reached 80. The radiation storm peaked at the arrival of the CMEs with the above 10 MeV proton flux reaching a high of 6310 pfu, the strongest radiation event since 2003.