Spatiotemporal variation of sandstorm and its response to vegetation restoration in Beijing-Tianjin sandstorm source area

Sandstorm is one of main environmental disasters that affect the social economic sustainable development in the Beijing-Tianjin area. The spatiotemporal variation of the sandstorm frequency and its correlations with meteorological factors and vegetation restoration were investigated based on the meteorological data collected from 26 stations during 1957-2007 in the sand source area of Beijing-Tianjin, and combined with the NDVI-dataset of GIMMS and SPOT-VGT. The results showed that the sandstorms frequency has showed a significant down trend in recent 50 years. Although it presented a slight increased trend after the year of 1999, the sandstorm frequency was far lower than that during 1950s-1960s. Wind and relative humidity were the most important factors that affected the sandstorm frequency in recent 50 years, and their contribution rates were 62.6% and 37.4%, respectively. The variation of the sandstorm frequency in the Beijing-Tianjin sandstorm source area was determined by vegetation cover and relative humidity to a great degree, their contribution rates were 32.7% and 44.5%, respectively. Vegetation cover was increased significantly in the Beijing-Tianjin sandstorm source area during 1982-2006, but the sandstorm frequently occur area showed no significant upward trend. The improvement of vegetation cover was remarkable after the implementation of the Sandstorm Source Control Project since 2000, especially in the area where sandstorms have frequently occurred. There is one year lag effect between vegetation cover and sandstorm in the Beijing-Tianjin sandstorm source area. Sandstorm frequency is closely related to vegetation cover of previous summer, especially in the desert steppe region where sandstorms have frequently occurred. It shows that the Sandstorm Source Control Project has played an important role in the alleviation of sandstorm occurrence.