What drives changes in aerosol properties over the Yangtze River Basin in past four decades？

Trend analysis of monthly mean AOD derived from near-full MERRA-2 (1980-2016), Terra (2000-2016) and Aqua (2002-2016) data records over YRB. The observed AOD values are presented in (a), while the deseasonalized MERRA-2 and MODIS AOD values are respectively shown in (b) and (c).311