Researchers say people using cellphones can blame storms that erupt on the sun's surface for some of their lost signals.

The fiery geysers, or solar flares, have been known to interrupt radio and television signals from satellites, but now a team of researchers, led by Queen's University professor David Thomson in Kingston, Ont., says the storms can also affect cellphones routed through towers with antennas facing the sun.

Dr. Thomson said his study found the rate of dropped calls could be as high as nine per cent in the summer. That number was calculated during one morning rush-hour in the U.S. Midwest.

He said the numbers would be similar in Canada.

The sun was beaming directly at the tower at the time. Communications towers remain more or less in a fixed position, he said.

The rate dipped to 0.5 per cent or 0.6 per cent at the same location in the winter, he said.

"We know [the link to dropped calls] is solar-related, but we don't know how exactly it happens," Thomson said.

The findings will be published in the next edition of the journal Proceedings of the Institute of Electrical and Electronics Engineers.

Solar flares eject about a billion tonnes of the sun's atmosphere into space, travelling at a speed of 1.6 million kilometres an hour. They cause the phenomenon known as the northern lights, or aurora borealis.

The flares are produced when the sun's magnetic energy becomes unstable and collapses, resulting in the explosive heating of vast amounts of gas.

There was peak of activity on the sun in 1989, when solar flares were blamed for a huge power outage in Quebec. Scientists have observed a cycle that lasts roughly 11 years.

Thomson said there was "minimum activity" reported in 1996. Things were relatively volatile again in 1999 and 2000, but "the sun is now pretty quiet," he said.