If you’d been asked to speculate as to what natural hazard the USGS would begin its 30 days of preparedness tips with, what would you have suggested?
Personally I might have suggested … let me think … well, certainly not Geomagnetic Storms. That’s something I don’t think about, although being a Canadian I love the Northern Lights. And I’m sure many others view the space between the planets as empty and therefore harmless. But it appears we should change our thinking, because Geomagnetic Storms are the natural hazard they chose.
And when you think about it, it makes sense: At a time when our dependence on technology is continuing to grow, “solar activity occurring miles outside Earth’s atmosphere can set our modern infrastructure spinning,” says the USGS. So obviously, there is a corresponding need to monitor and forecast these storms.
The USGS, as part of a partnership in the multi-agency National Space Weather Program “provides data to its customers and produces models of the Earth’s magnetic field that are used in a host of applications, including GPS receivers, military and civilian navigational systems, and in research for studies of the effects of geomagnetic storms on the ionosphere, atmosphere, and near-space environment.”
What are Geomagnetic Storms?
A stream of ionized gases, also known as solar winds, blows outward from the Sun’s ever-expanding corona at about 400 km/second (speed of light is 298,051 km/second) and varies in intensity with the amount of surface activity on the Sun. When the solar winds reach the earth, they encounter a shield – that’s the Earth’s magnetic field, the region of space behind it is the magnetosphere.
From time to time, depending on the sun’s 11-year cycle, flares, surges of high energy-charged particles (protons and electrons), penetrate the earth’s magnetic field and eventually come down into the atmosphere. Once there, the flares collide with oxygen and nitrogen molecules, decay, and then emit the visible light we see in auroras, as well as energy from the remainder of the electromagnetic spectrum before the magnetic field lines enter the earth’s body at the poles. These space weather effects are greatest at high latitudes in countries like Canada, which is more impacted than any other country in the world.
Geomagnetic Storms: Effects
Two of the more dramatic effects of geomagnetic storms on society are electrical blackouts, as the storms energize ground-induced currents (GIC) in electric power grids, and as flow meters in pipelines transmit erroneous flow information because of GICs using the pipelines as conductors.
In March of 1989, for instance, millions of people in Quebec Canada, in some areas of the U.S. northeast, and in Sweden were without commercial electric power for 9 hours as a result of a huge geomagnetic storm.
The impact of such a loss of electricity is difficult to imagine until it happens. I was fascinated, for instance, by the December 2009 Power Down episode of the American television crime drama NCIS in which many facets of life were stopped by an outage of power and law enforcement was forced to continue its work stripped of computers and high-tech forensics. Inventions like scanners, fax machines, photo copiers and e-mail were suddenly unavailable so the crew had to resort to Polaroid cameras, flash bars, and mimeograph machines. Do you remember those antiquated technologies?
Along with energizing ground-induced currents, large magnetic storms can also impact modern society by:
- Interrupting high frequency radio communication that utilize the ionosphere to reflect signals over long distances;
- Interfering with global-positioning systems when solar activity causes sudden variations in the density of the ionosphere;
- Disrupting oil and gas well drilling because the earth’s magnetic field, used to determine subterranean rock structures, becomes disturbed;
- Damaging satellites and affecting their operations. e.g. increased solar ultraviolet emission heats the Earth’s upper atmosphere, causing it to expand and create drag;
- Affecting airline activity by disrupting Omega system transmitters and causing inaccuracies amounting to several miles.
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