Scales for Stormy Space Weather
NOAA’s New Richter-Like Scales Predict
Impact of Upcoming Solar Max Space Storms

By Sareen R. Gerson
Federal Communicators Network

Everyone knows what the National Weather Service forecasts: earth weather. But how many of us are aware of space weather? You can track geomagnetic storms, solar flares, and other space weather alerts on the Space Environment Center’s website but why bother, unless you’re an astronaut?

Fact is, space weather, influenced largely by the sun, affects daily life on earth far more than most people imagine. Especially during a Solar Maximum, the peak of every 11-year solar cycle (we’re in Cycle 23 right now), solar winds buffeting the earth’s magnetosphere generate huge and sometimes very severe geomagnetic storms that can and do cause power outages, radio and satellite malfunctions, and pager and cell phone failures. With communications, these days, depending so heavily on satellites, and the numbers of satellites increasing, space weather can no longer be considered a concern only for scientists.

Predicting the solar max effects, however, has just been improved. The National Oceanic and Atmospheric Administration (NOAA) has reinvented the communication of methods used to present data on the effects of geomagnetic storms, making them far more accessible to the public and to companies and industries that need the information.

Like the Richter Scale

At the Commerce Department in Washington on November 9, NOAA officials announced a new set of scales for characterizing the effects of the upcoming space storms. The various strengths of the storms are rated, G1 for a minor storm, up to G5 for one that is extreme -- much as earthquakes are measured on the Richter scale. Descriptions of the effects on power systems, spacecraft, pipelines, radio, etc., accompany each rating. The NOAA Space Weather Scales also include scales, with accompanying descriptions of the effects, for radio blackouts (R1, minor, to R5, extreme), and for solar radiation storms (S1, minor, to S5, extreme).

All of the scales are being made available to the general public. And they are, indeed, easy -- and a little scary -- to read. According to the S1-S5 scale, for example, an extreme solar radiation storm can cause radiation doses equivalent to a chest X-ray to passengers in highflying aircraft at high latitudes, and high radiation hazards to astronauts working outside a spaceship. But for the first time, said Dr. D. James Baker, under secretary for oceans and atmosphere at Commerce, and NOAA administrator, "We can predict the impact of solar storms." Dr. Baker said that the space storms may be a real problem in 2001.

During the upcoming solar maximum, the peak of Solar Cycle 23, scientists believe there is a potential for public safety problems. Customers for space weather information in the 50s were mostly people interested in short-wave radio. Now, say the experts at the Space Environment Center (run by NOAA and the U. S. Air Force) urgent queries are increasing concerning weather satellites, GPS navigation, ozone measurements, aircraft radiation hazards, and of course relays for commercial TV. Pipelines for gas and oil can be corroded by induced ground currents reaching hundreds of amps. Radio blackouts would mean that low-frequency navigation signals used by maritimne and general aviation systems would experience outages on the sunlit side of the earth, causing loss in positioning. All of these effects are brought on by the turbulence far above.

In March, 1989, during the last solar maximum, major solar flares and the resulting space storm knocked out the electrical system throughout Quebec and destroyed a large power transformer in New Jersey. Ten years ago, computers could not cope quickly enough with scientific observations to provide alerts. Now that high tech capabilities have vastly increased, warnings, watches and forecasts can be issued, albeit not so far in advance as might be hoped. But at least the general public can be made more aware of the impact on their daily lives as well as on navigation, power distribution, and radio communications systems.

Sunspots Increasing

The number of sunspots is an indicator of the increasingly turbulent solar activity which includes the ejection of clouds of hot solar gases and proton jets, causing gusty solar winds. You can track the "Sunspot Number" daily; it is being published by NOAA and is also on a special NASA website, http://www.sunspotcycle.com. On 9 November, for example, it was 232. It had been only 194 on 1 November. Sunspots, which long ago were thought to be satellites of the sun, but are known now to be gaseous, have been recorded since the 17th century, by the early scientists Galileo, Thomas Harriot, Johannes and David Fabricius, and Christoph Scheiner. (For some printable images of their 17th century sunspot drawings, go to the Rice University site.

But -- a cautionary -- best leave direct sunspot counting and observing to the scientists who have special equipment: no one should ever look directly at the sun, or through a telescope, binoculars, or any other viewing device, as serious retinal damage and blindness can result.

A Bright Spot: the Northern Lights

For those who have never had a chance to view the beautiful Aurora Borealis, which is usually visible only in the northern latitudes, there’s one small bonus ahead. During the solar maximum, these shimmering curtains of red and green light in the sky will be visible much further south. As a matter of fact, the southward tour of the aurorae is also charted on the NOAA scale: Minor space storm? The aurora will be visible at high latitudes (60 degrees); moderate, 50 degrees; strong, as low as mid-latitudes; severe, as low as the tropics, and -- believe it or not -- during an extreme geomagnetic storm (G5 on the NOAA scale), the aurora will be seen as low as the equator.

About the Author

Author Sareen Gerson from the Occupational Safety and Health Administration is a member of the Federal Communicators Network. You may write her at Sareen.Gerson@osha-no.osha.gov.

November 22, 1999