LHASA - Southwest China's Tibet autonomous region has witnessed a trend of significantly reducing sandstorms in the past 50 years, according to an official bulletin released on Thursday.

From 1961 to 2012, the records of the region's 18 meteorological stations show that the number of days with sandstorms per decade reduced by 26.4 days on average, said the Tibetan Climate Change Detection Bulletin.

Du Jun, deputy director with the Tibetan climate center, attributed the trend to calmer wind speed and a declining number of windy days in the autonomous region.

In the past five decades, the average wind speed in Tibet has lowered by 0.1 meters per second per decade, the number of windy days have also been decreasing at 9.8 days per decade.

The calming upper westerly jet steam is the main factor that led to the weakening wind speed and decline in the number of days with high wind. And the region's increasing vegetation coverage is also helpful in reducing sandstorms, said Du.

Tibet has a forested area of 14.71 million hectares, which endows the region with a forest coverage rate of 11.98 percent, thanks to multiple major afforestation and desertification control projects.