Abstract:

By using long-time series remote sensing observations， surface meteorological observations， and air quality monitoring data， the underlying surface improvement of Hunshandak Sandy Land and the characteristics of spring sand-dust weather since the implementation of the Beijing-Tianjin Sand Source Control Program were analyzed. The results showed that compared with the years 2000 to 2009， the vegetation coverage significantly increased in over 22% of the Hunshandak Sandy Land from 2010 to 2022. The sand-dust weather in the Hunshandak Sandy Land mainly occurred under the influence of westerly winds， showing a trend of first decreasing and then increasing.. The period from 2000 to 2006 was a period of frequent occurrence of sand-dust weather. From 2007 to 2014， the number of sand-dust days decreased， and the number of sand-dust days increased again from 2015 to 2023. The trend of the sand-dust days was consistent with the trend of strong winds above level 6. The decrease in the number of strong winds combined with the decrease in the frequency of sand formation had led to a significant decrease in the proportion of sand formation times under the influence of strong winds above level 6， from nearly 80% at the beginning of this century to around 30%-40% in recent years. As a result， the sand-dust weather under lower wind speeds had seen a significant increase. From 2012 to 2023， the impact of sand-dust weather from overseas was becoming increasingly significant in the Hunshandak Sandy Land. Compared to local sand-dust weather， the impact range of sand-dust weather from overseas was larger.

Key words: Hunshandak Sandy Land, vegetation coverage, sand formation, temporal and spatial distribution characteristics, regional sand-dust weather