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As GNSS users, it is import to know what is happening with solar activity, especially now as we are entering a solar maximum. Over the past few days the solar activity has picked up, with three X-Class solar flares within the last 24 hours. These are the strongest flares of the year so far, and they signal significant increase in solar activity. The source of the flares, a large sunspot on the sun’s eastern limb, appears poised to erupt again as it turns toward earth.

You may be asking, what is an X-Class solar flare, and how will it affect me and my GNSS? Here is a little background  from Accuweather that will hopefully answer those questions.

Solar flares are giant explosions on the Sun that send energy, light and high speed particles into space. These flares are often associated with coronal mass ejections (CMEs). The number of solar flares increases approximately every 11 years, and the Sun is currently moving towards another solar maximum, likely in 2013. That means more flares will be coming, some small and some big enough to send their radiation all the way to Earth.

The biggest flares are known as “X-class flares” based on a classification system that divides solar flares according to their strength. The smallest ones are A-class (near background levels), followed by B, C, M and X. Similar to the Richter scale for earthquakes, each letter represents a 10-fold increase in energy output. So an X is 10 times an M and 100 times a C. Within each letter class there is a finer scale from 1 to 9.

Although X is the last letter, there are flares more than 10 times the power of an X1, so X-class flares can go higher than 9. The most powerful flare measured with modern methods was in 2003, during the last solar maximum, and it was so powerful that it overloaded the sensors measuring it. The sensors cut out at X28.

If they’re directed at Earth, such flares and associated CMEs can create long lasting radiation storms that can harm satellites, communications systems and even ground-based technologies and power grids. X-class flares on Dec. 5 and 6, 2006, for example, triggered a CME that interfered with GPS signals being sent to ground-based receivers.

For more information, or to sign up for solar activity alerts, go to www.spaceweather.com