Dolores Beasley

Headquarters, Washington, DC

(Phone: 202/358-1753)

Susan Hendrix

Goddard Space Flight Center, Greenbelt, MD

(Phone: 301/286-7745)

Jana Goldman

National Oceanic and Atmospheric Administration, Silver
Spring, MD

(Phone: 301/713-2483, ext. 181)

RELEASE: 00-199

As the Sun’s stormy season approaches its zenith, solar
scientists have the best seat in the house, using the largest
coordinated fleet of spacecraft and ground observatories ever
assembled to observe these angry outbursts of solar radiation
and predict the impact of turbulent space weather.

According to scientists from NASA and NOAA, the Sun is near
the peak of its 11-year cycle of activity. Solar maximum is
the two-to-three year period around that peak when the Sun’s
activity is most tempestuous and the Earth is buffeted with
powerful solar gusts.

“This is a unique solar maximum in history,” said Dr. George
Withbroe, Science Director for NASA’s Sun-Earth Connection
Program. “The images and data are beyond the wildest
expectations of the astronomers of a generation ago.”

By combining sophisticated new instruments and time-tested
older ones, researchers believe their predictions and warnings
related to space weather events are becoming more accurate and
timely. “The new results from space feed directly into NOAA’s
plans and programs for forecasting space weather and its
effects on Earth and technological systems,” said Dr. Ernest
Hildner, director of NOAA’s Space Environment Center in
Boulder, CO.

The coordinated use of NASA and NOAA technology was key in
tracking and predicting the development of an intense solar
storm nicknamed the “Bastille Day Event.” With data from
ground-based observatories, the Solar and Heliospheric
Observatory – a joint project of the European Space Agency and
NASA – and NOAA’s Geostationary Operational Environmental
Satellites, scientists were able to anticipate a bright solar
flare and ensuing energetic proton shower July 13.

The flare coincided with a coronal mass ejection (CME) which
sent billions of tons of plasma into space traveling at 4
million miles per hour, two times faster than normal.

NOAA forecasters, using data from the Advanced Composition
Explorer (ACE), typically can provide about one hour notice of
prospective magnitude before the start of a geomagnetic storm.
But the July solar shower blinded key ACE detectors. Without
reliable data, scientists and forecasters had to wait until
Earth’s magnetic field became distorted before they knew that
the disturbance had arrived.

A G5 geomagnetic storm – the most intense classification –
raged for nearly nine hours after the solar shower’s impact.

The effects of the July storm were widespread. Cameras and
star-tracking navigation devices on several satellites were
flooded with solar particles. Measurements from particle
detectors and other instruments on several NOAA and NASA
spacecraft were either degraded or temporarily shut down. The
Japanese Advanced Satellite for Cosmology and Astrophysics
(ASCA) was sent tumbling in orbit.

On the ground, auroral light shows were seen as far south as
El Paso, TX. Power companies suffered geomagnetically induced
currents that tripped capacitors and damaged at least one
transformer. Global positioning system (GPS) accuracy was
degraded for several hours. “The July event was a surprise to
some of our customers,” Hildner said. “They haven’t seen this
kind of activity for nearly a decade.”

A number of international spacecraft provided extensive data
and images showing the development and character of the July
event. “The next generation of solar missions will complement
and improve upon what scientists are learning from the
existing fleet, Withbroe said. “This will provide us with even
more capability to understand and ultimately predict solar
weather and its effect on Earth.”

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