Estimations of indirect and direct anthropogenic dust emission at the global scale

Abstract

Dust emission acts as a crucial part in the dust cycle that determines dust related processes at both regional and global scale, such as long-range transport, dry/wet deposition, and radiation forcing. However, most dust emission simulations utilizing dust emission scheme merely investigate natural dust, neglecting the contributions of anthropogenic dust induced by direct or indirect anthropogenic activities, resulting in great uncertainties in estimating dust emissions by previous numerical modelling. To comprehensively reproduce the anthropogenic dust emissions process, both “indirect” and “direct” anthropogenic dust emission schemes were constructed to simulate anthropogenic dust emissions originated from diverse kinds of source regions in the study. Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) retrievals were utilized as the constraint of anthropogenic dust simulations. Results showed that using both indirect and direct anthropogenic dust emission schemes show good performance on reproducing the spatio-temporal distributions of anthropogenic dust at the global scale during 2007–2010. High value centers of anthropogenic dust emission fluxes locate in India, the east of China, North America, and Africa. Compared with natural dust emissions, indirect anthropogenic dust emissions show an indistinctive seasonal variation, with seasonal differences generally less than 0.42 μg m−2 s−1. Among indirect anthropogenic dust emissions, pasturelands produce more anthropogenic dust particles emission into the atmosphere than croplands at approximately 0.28 μg m−2 s−1, contributing 75.9% of indirect anthropogenic dust emissions. The developing regions emit much higher direct anthropogenic dust emissions than those from developed regions. This study reveals the non-negligible environmental problems especially in urban areas due to anthropogenic dust.