NOAA issues solar radiation warning

Robin Wulffson MD's picture
radiation, solar flare, NOAA, navigation, communication
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On January 23, the National Oceanic and Atmospheric Administration’s (NOAA) Weather Prediction Center issued a geomagnetic storm warning after a satellite witnessed an ultraviolet flash from the massive solar eruption. Radiation from the immense solar blast hit the Earth on January 24, caused Delta Air Lines to redirect at least half a dozen aircraft that had a planned route over the North Pole. The rerouting of flights between Hong Kong and the United States was done as a precautionary measure to avoid exposing flight crew and passengers to excessive radiation as well as to avoid communication disruptions. The flare led to the largest radiation storm of its kind since 2005.

According to the nation’s official source of warnings regarding space weather and its impact on Earth, the eruption poses no risk to humans on the Earth’s surface. The changes, which are primarily intended to prevent loss of radio communication, affected approximately six Delta flights on January 24. The airline will reevaluate the situation on January 25 to determine whether additional changes will be required.

Kathy Sullivan, deputy administrator of NOAA, first suggested that rerouting might be necessary on the morning of January 23 at a Meteorological Society meeting in New Orleans, LA. Solar eruptions blast huge streams of charged particles away from the sun, in this case directly towards the Earth.

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Both NASA and NOAA monitor for solar eruptions, as they could cause problems for astronauts, communications satellites, and even rocket launches. They could also disrupt navigation and the power grid. The NOAA report read: "A [coronal mass ejection (CME)] hit Earth's magnetic field on Jan. 24th at approximately 1500 UT (10 am EST). Geomagnetic storms are likely in the hours ahead. If it's dark where you live, go outside and look for auroras." At the time of the release, auroras were already clearly visible in the skies over Scotland and Northern England.

The solar flare referred to in the report was rated an M9-class eruption–– nearly an X-class flare, the most powerful type of solar storm. NASA spokeswoman Kelly Humphries told space.com the six astronauts currently living and working on the International Space Station are not in any danger. She explained, "The flight surgeons have reviewed the space weather forecasts for the flare and determined that there are no expected adverse effects or actions required to protect the on-orbit crew."

NOAA measures geomagnetic storms on a five-point scale from 1 to 5. G1 storms are minor, leading to weak power grid fluctuations and having only minor impact on satellites. G5 storms are extreme, leading to widespread voltage control problems, damage to transformers, radio outages and satellite problems. NOAA warned of geomagnetic storms on January 24, also a result of the flare. They were predicted to be as strong as G3, which would cause intermittent navigation problems on Earth and low-Earth satellites.

Solar activity waxes and wanes on an 11-year cycle. Currently, activity in Solar Cycle 24 is expected to increase toward a "solar maximum" in 2013.

Source: NOAA

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