BEIJING, March 13 (Xinhua) -- Solar storms, which are expected to get worse over the next five years, could threaten China's national defence and communications satellite systems, said the National Satellite Meteorological Center (NSMC) on Tuesday.

Solar storms on the surface of the sun create solar winds in space that slam the earth's atmosphere, disrupting its magnetosphere, ionosphere and thermosphere.

These atmospheric disruptions can affect the country's aerospace program, including its satellite systems that provide communications, defense monitoring, navigation and global positioning, said sources with the NSMC which falls under the China Meteorological Administration.

Solar activity will enter a new upward phase this summer. It will be at a low ebb in May and after passing this stage, will increase gradually and reach the cycle's peak in 2012, according to the center.

The sun's cycles last 11 years and the one beginning this summer will be the 24th since the first solar cycle was recorded in 1755, said the sources.

Experts suggest the sun's activities and the space weather they create should be constantly monitored and forecasts provided to organizations and firms involved in aerospace so they can put emergency plans in place if disruptions occur.