Spatio-temporal trends of dust emissions triggered by desertification in China

The spatial and temporal trends of potential dust emissions from severe aeolian desertified lands and Gobi desert surfaces in China were investigated based on field sample collections, wind tunnel experiments, and historical wind records. The results showed that aeolian desertified lands and Gobi desert surfaces are both key landscapes for dust emissions. The dust emission rate in Gobi deserts was approximately 19% of what originated from desertified lands at the beginning of the 1970s but this ratio increased to 26% in 2015. Considering temporal variations of dust emission over aeolian desertified lands and the Gobi desert surfaces, from the 1980s to the present, the contribution of the Gobi desert surfaces on dust emissions decreased from 71% to 31% of that originating in desertified lands. From the 1970s to 2015, the average amounts of PM2.5 (particulate matter with diameter less than 2.5 μm), PM5, PM10, and PM50 emitted from desertified lands are 17.6, 29.4, 39.6, and 65.2 Tg yr−1, while that of PM5, PM10, and PM50 emitted from the Gobi desert surfaces are 18.4, 26.5, 40.4 Tg yr−1, respectively. Compared with that in the 1970s, potential dust emissions after 2000 from desertified lands and the Gobi desert surfaces decreased by 75% and 71%, respectively. In addition, the wind tunnel experiment results and statistics indicate that the potential dust emissions in China are far lower than that of model simulations. There are significant spatio-temporal variations in the potential dust aerosol source areas and intensities of dust emissions in China over the past decades.