Variation of Dust in Northern China and Its Reproduction in BCC-ESM1 since 1980

In this paper, we explore the possible causes and mechanisms for the variation of dust in northern China from 1980 to 2014 using the Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2) data, observational data, and BCC-ESM1 (Beijing Climate Center Earth System Model version 1) simulation data. Two important dust centers are identified in China: one in the Taklamakan Desert in southern Xinjiang Region and the other in the Badain Jaran Desert in western Inner Mongolia Plateau. Both centers display distinct seasonal variations, with high dust concentration in spring and summer and low in autumn and winter. BCC-ESM1 is able to generally capture the main spatial and temporal characteristics of dust in northern China. Both the MERRA-2 reanalysis data and BCC-ESM1 simulation data show a decreasing trend in spring dust, which is evident during 1980–2000 and 2001–2014. The analysis based on daily mean dust loads and wind fields from MERRA-2 and BCC-ESM1 indicates that dusty weather in North China may be mainly caused by transport of the dust, especially that from the central and western Inner Mongolia Plateau during the prior 0–2 days, through the westerly winds from the upstream “dust core” region (38°–45°N, 90°–105°E). This is one of the important paths for dust to move into North China. The weakened westerly wind in the lower troposphere in this “dust core” region may be responsible for the reduction of spring dust in North China.