Spatiotemporal variation in the occurrence of sand-dust events and its influencing factors in the Beijing-Tianjin Sand Source Region, China, 1982-2013

摘要

The Beijing-Tianjin Sand Source Region (BTSSR) is an ecological barrier for Beijing, the capital of China. Exploration of the spatiotemporal patterns of sand-dust weather and their influencing factors is important for effective management of regional environments. Changes in patterns of sand-dust weather days from 1982 to 2013 were analyzed based on remote sensing and meteorological observation data, and the contributions of meteorological and vegetation factors to the variation in sand-dust events at the regional and sub-regional scales were investigated. The results showed that the number of sand-dust weather days in the BTSSR decreased with decreasing wind speed and variations in precipitation and vegetation restoration, from 24 in 1982 to 5 in 2013. The occurrence of sand-dust weather was related mainly to the mean wind speed during March and May, the cumulative precipitation from the antecedent July to the concurrent June, and the maximum vegetation cover of the antecedent year. These factors could explain 76.4% of the variation in sand-dust events, with meteorological factors, including wind speed and precipitation, contributing about 57%. The spatiotemporal patterns of sand-dust weather and their specific influencing factors were spatially heterogenous. In 70% of sub-regions, the influencing factors explained at least 50% of the variation in sand-dust events. Although meteorological factors dominated, the function of vegetation in the variation in sand-dust weather could not be ignored, with contributions of 26-48%. Existing eco-restoration projects (e.g., reforestation and afforestation, enclosure of grassland) should be effectively managed and protected to maintain vegetation and reduce the sand-dust event risk.