Steve Nichols
Worldwide HF and satellite communication systems could soon be severely disrupted if scientists' predictions come true.
The sun's current 11-year solar cycle is predicted to peak this year, and the increase in sunspot activity and solar flares could cripple vital aircraft communication and navigation systems.
While solar activity is needed to maintain HF links around the world, massive activity can cause so much ionisation that signals are completely absorbed.
The reliance of many aircraft systems on satellite navigation adds another headache.
While GPS and other systems use frequencies not normally affected by sunspot activity, scientists are worried that the satellites themselves could be temporarily blinded or even destroyed by charged particles streaming out from the sun.
In 1986, the Canadian communications satellite Anik E-1 was knocked out by solar flares.
The most violent space storms occur when magnetic field lines in the solar wind connect with those that surround the earth, creating a funnel that channels huge quantities of solar plasma into the magnetosphere.
Powerful currents then surge through atmosphere, where they can scramble broadcast signals, interrupt transatlantic phone conversations and overheat electrical transformers. In 1989, during the last solar maximum, currents induced by a geomagnetic storm brought down the power grid that supplies Canada's Quebec province.
The peak of cycle 23 "...will be one of the largest on record, and comparable to the last two solar cycles," says a panel of international experts chaired by Jo Ann Joselyn of the US National Oceanic and Atmospheric Administration's Space Environment Center in Boulder, Colorado.
While scientists always thought that solar activity couldn't affect the SHF GPS navigational signals, they are now less optimistic. One suggestion is that the massive ionisation could cause the signals to scatter or scintillate causing location errors. Other scientists fear that radar systems could also be affected.
Source: Flight Daily News
