The worst of the sandstorms are over for the year, but a few more are likely to hit southern parts of northwest China's Xinjiang Uygur Autonomous Region.

"As for Beijing, a city in the shadow of northern China's frequent sandstorms, the worst period will also to be gone with the spring," Zhang Guocai, director of the China Meteorological Administration's (CMA's) Department of Disaster Reduction and Prediction, said on Thursday in Beijing.

However, he said, the storms remain "an issue darkening the spring skyline in northern China."

So far this year, China has experienced 17 drifting or flowing sand weather systems, including one strong sandstorm, five average storms and 11 drifting or flowing sand phenomena, said Zhang

The March 26 to 30 sandstorm was the worst this spring. It delayed more than 1,200 flights, including 130 at the Beijing Capital International Airport, with 20 others forced to land at airports in Tianjin, Zhengzhou, Taiyuan and Dalian.

A dust storm on March 9 to 11, the largest this spring, swept more than 19 provinces, autonomous regions and major cities in north China, as well as areas along the middle and lower reaches of the Yangtze River.

Zhang reviewed the frequency, features, intensity and impact of the sandstorms this year, reporting that more occurred this year than in the same period in 2003.

Recent studies of sunspots found that solar activity affects sandstorms in China. The storms are likely to increase for a period around 2030 as solar activity changes, Chinese scientists predict.

Since 2,000, there have been 67 sand drifting or sandstorm weather phenomena, with an annual average frequency of 13.4, according to the CMA.

So far this year, 14 such phenomena have occurred in north, northwest and northeast China, with less intensity and of shorter duration than the previous year.

Most took place in March as temperatures climbed rapidly in north China, running 1 or 2 degrees Celsius above the average. This led to an earlier thaw of the frozen surface ground, and then a prolonged dry spell in early spring and cyclones from Inner Mongolia caused by frequent cold air currents loosened surface earth and dust.

To mitigate damage, the CMA started daily sandstorm forecasting in 2001, with early warnings issued through TV, radio and other media across China.

The CMA can forecast sandstorms three days in advance, Zhang said.

A national early warning system for large-scale dust and sandstorms began trial operations this year.

The system consists of 24-hour observation by ground meteorological stations and remote sensing, and satellite data transmission.

(China Daily May 21, 2004)