The Dangers of Space Weather
Economies around the world have become increasingly vulnerable to the ever-changing
nature of the sun. Solar flares can disrupt power grids, interfere with high-frequency airline
and military communications, disrupt Global Positioning System (GPS) signals, interrupt civilian
communications, and blanket the Earth's upper atmosphere with hazardous radiation.
Monitoring and forecasting solar outbursts in time to reduce their effect on space-based technologies
have become new national priorities. And NOAA's Space Weather Prediction Center (SWPC), part of NOAA's
National Weather Service, is the nation's official source of space weather forecasts, alerts, and warnings.
Why Forecasting Space Weather is Important
"The Space Weather Prediction Center is critical to our economy because each time we use a cell phone or pager,
check a GPS locator, turn on a light, or take an over-the-pole flight, space weather could have an effect,"
said Jack Hayes, Ph.D., director of NOAA's National Weather Service.
Monitoring Space Weather
To monitor events on the sun, SWPC scientists and technicians utilize a variety of ground- and space-based
sensors and imaging systems to view activity at various depths in the solar atmosphere. A worldwide
network of USAF-sponsored optical observatories also provides space weather forecasters with detailed,
plain-language information about activity in and around sunspot groups, as well as other areas of interest
on the sun.
Space weather forecasters also analyze the 27-day recurrent pattern of solar activity. Based on a
thorough analysis of current conditions, comparing these conditions to past situations, and using
numerical models similar to weather models, forecasters are able to predict space weather on times
scales of hours to weeks.
Responding to Space Weather Warnings
With effective alerts and warning, we can limited the effects of space weather on real-time technology.
For example, satellites can be adjusted, power grids can be modified, and polar flights can be rerouted.
Scientists and forecasters work closely with government and university partners to develop prediction
models and other tools to improve services to the nation's space weather community. SWPC also helps move
the latest computer models of solar dynamics and sun-Earth interactions into the daily operations of space
NOAA and partner agencies in the National Space Weather Program are leading the way in this new era of
space weather awareness to provide timely, accurate information and forecasts to help keep our
advanced-technology global economy moving forward.
Accurately Predicting Solar Flares
For decades, experts have searched for signs in the sun that could lead to more accurate forecasts of
solar flares - powerful blasts of energy that can supercharge Earth's upper atmosphere and disrupt satellites
and the land-based technologies on which modern societies depend. Now a scientist at NOAA's Space Weather
Prediction Center and her colleagues have found a technique for predicting solar flares two to three days
in advance with unprecedented accuracy.
The long-sought clue to prediction lies in changes in twisting magnetic fields beneath the surface of the sun
in the days leading up to a flare, according to the authors. The findings were published in the February 2010
issue of Astrophysical Journal Letters.
"For the first time, we can tell two to three days in advance when and where a solar flare will occur and how
large it will be," said lead author Alysha Reinard, a solar physicist at NOAA's Space Weather Prediction Center
and the Cooperative Institute for Research in the Environmental Sciences, a partnership between NOAA and the
University of Colorado.
The new technique is already twice as accurate as current methods, according to the authors, and that number is
expected to improve as they refine their work over the next few years. With this technique, reliable watches and
warnings should be possible before the next solar sunspot maximum, predicted to occur in 2013. Currently, forecasters
see complex sunspot regions and issue alerts that a large flare may erupt, but the when-and-where eludes them.
What Are Solar Flares?
Solar flares are sudden bursts of energy and light from sunspots' magnetic fields. During a flare, photons travel
at the speed of light in all directions through space, arriving at Earth's upper atmosphere-93 million miles from
the sun-in just eight minutes.
Problems Caused by Solar Flares
Almost instantly the photons can affect the high-orbiting satellites of the Global Positioning System, or GPS, creating
timing delays and skewing positioning signals by as much as half a football field, risking high-precision agriculture,
oil drilling, military and airline operations, financial transactions, navigation, disaster warnings, and other critical
functions relying on GPS accuracy.
Why Solar Flare Predictions are Valuable
"Two or three days lead time can make the difference between safeguarding the advanced technologies we depend on every
day for our livelihood and security, and the catastrophic loss of these capabilities and trillions of dollars in disrupted
commerce," said Thomas Bogdan, director of NOAA's Space Weather Prediction Center.
Reinard and NOAA intern Justin Henthorn of Ohio University pored over detailed maps of more than 1,000 sunspot groups,
called active regions. The maps were constructed from solar sound-wave data from the National Science Foundation's Global
Oscillation Network Group.
Reinard and Henthorn found the same pattern in region after region: magnetic twisting that tightened to the breaking point,
burst into a large flare, and vanished. They established that the pattern could be used as a reliable tool for predicting a solar flare.
"These recurring motions of the magnetic field, playing out unseen beneath the solar surface, are the clue we've needed
to know that a large flare is coming-and when," said Reinard.
|What is a Solar Flare? A solar flare is an intense burst of radiation coming from the release of magnetic energy associated with sunspots. We typically see a solar flare by the photons (or light) it releases, at most every wavelength of the spectrum. The primary ways we monitor flares are in x-rays and optical light. Flares are also sites where particles (electrons, protons, and heavier particles) are accelerated. NOAA image. Enlarge Image
|Forecasters at NOAA's Space Weather Prediction Center in Boulder, Colorado. NOAA image.|
|Twisting magnetic fields beneath the surface of the sun erupt into a large solar flare, as shown above. NSF image. Enlarge Image