Triggered by a force-5 wind, floating-dust weather occurred in Beijing on April 14, leaving poor visibility of about 2,000 meters in the afternoon. However, meteorological experts said the phenomenon was not a sandstorm, and sandstorm frequency in Beijing this spring has definitely declined.
?So far, no sandstorm has hit Beijing since the start of the spring season,? said Li Tingfu, senior engineer from the Municipal Meteorological Observatory.
Statistics show that floating-dust weather and strong sandstorms hit Beijing 10 and 8 times from January to April in 2001 and 2002 respectively, Li explained. The main reasons given were successive years of drought and frequent cold air striking northern China in spring, and of course the devastation of its ecology and vegetation.
According to Li, four reasons lead to the decreased frequency of sandstorms in northern China, including Beijing, this year.
First, precipitation in most parts of north China this year, from winter to spring, is about 50 percent larger and soil moisture has been at its best, compared with the same period in previous years. These areas include the Xinjiang Uygur Autonomous Region, Inner Mongolia Autonomous Region, Gansu Province and Qinghai Province. Precipitation in Beijing reached 54.1 mm since January, with the figure standing at 33 mm for March only, said Li. The large rainfall has increased the moisture content of the earth and helped curb the frequency of sandstorms.
Second, cold air mass has been comparatively weak this spring. So far, few strong cold air masses have hit the country, especially in northern areas. On the contrary, weak cold air has brought increased precipitation.
Third, this spring marks the beginning of a new El Ni?o phenomenon, which helps reduce sandstorm frequency.
Fourth, ecological projects carried out by the Chinese government in the past number of years have increased vegetation coverage that deters flying sand.
However, the fact that sandstorms haven?t hit Beijing yet doesn?t mean they won?t, experts said. So far though, no signs have indicated that sandstorms will not hit Beijing this spring. But since mid April, plants in north China have been turning green and the vegetation coverage will help control the movement of sand in the air. Usually, the frequency of sandstorms, especially strong-level sandstorms, abates after May.
(China.org.cn translated by Zhang Tingting and Li Jingrong, April 16, 2003)
