OCTOBER-NOVEMBER 2003 SOLAR STORM

The solar storms that impacted the Earth between Oct. 19 to Nov. 7, 2003, further justify the benefits of NOAA space weather activities and remind the nation that space weather can be hazardous to Earth and space systems at any time during the 11-year solar cycle. This storm came as quite a surprise, since it occurred three-and-a-half years after solar minimum, when things are relatively quiet on the sun compared to solar maximum.

"It's like seeing a hurricane in November rather than August, when you'd typically expect it," commented Larry Combs, one of the NOAA Space Environment Center forecasters. “What also made these storms unusual is that there were two distinct, very intense geomagnetic storms, which both arrived in just 19 hours from the sun to the Earth. This ranks them as some of the fastest traveling solar storms on record and both produced the strongest activity this solar cycle — reaching extreme or G5 on the NOAA space weather scales." Because the NOAA Space Environment Center released advanced warnings about an unusually large solar storm, electrical utilities, airlines and spacecraft managers were able to take preventive action to minimize disruption of service — and the economy — due to the storm.

Impacts of this space weather storm are summarized below:

• International Space Station: During the high solar activity, NASA decided to do a ground-commanded power down of the billion dollar robotic arm and workstation, which are highly sensitive to radiation events. The crew onboard the space station also took shelter in the service module during the peak exposure times.
• Satellites: Approximately 59 percent of the Earth and space science missions (both deep space and near-Earth missions) experienced effects from the October-November 2003 activity. As a result, about 24 percent of the space missions either turned off their instruments or took other protective action. These mitigating actions were crucial for many satellites, but one Japanese satellite (ADEOS-2, worth $640 million) is believed to have failed completely due to this storm (Murtagh, personal communication). The storm was so intense that the NASA/European Space Agency's SOHO satellite and the German satellite CHAMP failed temporarily, while the NASA satellite ACE was damaged beyond repair (Murtagh, personal communication).
• Communications: The storm did interfere with high frequency radio communications for teams on Mount Everest and some satellite based communications companies (TV and radio) reported several short-lived interruptions. It is important to note that actions not taken due to accurate assessment and prediction of the space environment are also very important. For example, SEC staff worked closely with a satellite company that provides high-resolution satellite imagery to a huge customer base that includes multiple U.S. Department of Defense agencies. Company management was prepared to “safe” the satellite in late October to avoid space weather damage and estimated the cost of such action at several million dollars per day. However, because SEC staff accurately predicted that space weather storm levels would remain below their “safing” threshold, the company was able to maintain continuous operations through the storm (NOAA NWS Service Assessment, 2004).
• Airlines: NOAA SEC staff participated in teleconferences with major airlines at an average rate of three to five times a day during the October and November 2003 activity. With SEC help, airlines were able to make critical decisions about route and/or altitude restrictions to flight operations during solar activity. Flight Centers restricted flight paths on several occasions due to degraded communications, but it was each individual airline’s responsibility to respond to the radiation threat.
• Navigation: LORAN-C (ground-based radio-conveyed navigation system) reported numerous interference problems and GPS users reported degradation and outages with some applications.
• Power Grids: The NOAA SEC warned the power companies of the impending solar storm using the standard SEC suite of geomagnetic storm watches, warnings and alerts — plus supplemental SEC support provided by phone. Although power grids from Wisconsin to Virginia experienced minor problems, they were successfully mitigated so as not to allow catastrophic blackouts in the United States. Responses to warnings included reducing system load, disconnecting system components and postponing maintenance. A power grid in southern Sweden, however, experienced a one hour blackout.

References
Murtagh, W., personal communication. March 31, 2004. NOAA Space Environment Center. Boulder, Colo. Email: William.Murtagh@noaa.gov.

NOAA NWS Service Assessment, March 2004. Intense Space Weather Storms October 19 – November 07, 2003. U.S. DEPARTMENT OF COMMERCE. National Oceanic and Atmospheric Administration. National Weather Service. Silver Spring, Md. http://www.sec.noaa.gov/info/SWstorms_assessment.pdf