Publications

He, LJ; Wang, LC; Lin, AW; Zhang, M; Xia, XG; Tao, MH; Zhou, H (2018). What drives changes in aerosol properties over the Yangtze River Basin in past four decades ?. ATMOSPHERIC ENVIRONMENT, 190, 269-283.

Abstract
Since the Reform and Opening up in China, aerosols increasingly affect the country's climate change and human health. However, remote sensing studies have been inconclusive as to long-term trends in Chinese aerosol emissions. The newly-released MERRA-2 product provides a long-term (1980 onward) aerosol reanalysis dataset, and thus is used in this study for identifying trends in aerosol optical depth (AOD) and aerosol direct radiative effect (ADRE) in clear sky over the Yangtze River Basin (YRB) based on the MK nonparametric method. Results reveal that there is a notable turning point in AOD trends around 2008, i.e., significantly increasing by 0.0201 year(-1) before 2008 and then deceasing by -0.0185 year(-1). The reason may be the decreases of SO2, NOx and soot (dust) emissions from major cities in the YRB since 2006. Likewise, the cooling (warming) effects at the top of atmosphere (TOA), surface (SFC) and atmosphere (ATM) strongly increase by -0.3744 and -0.5652 (0.2935) wm(-2) year(-1) before 2008, and then significantly decrease by 0.2731 and 0.5868 (-0.3145) wm(-2) year(-1). Trend analyses confirm that changes in AOD dominate ADRE trends. Furthermore, AOD is significantly negatively (positively) associated with NDVI and precipitation (GDP and Population density) over most areas of the YRB. Besides, similar spatial trends with AOD are also identified in GDP and NDVI. This indicates that increases in GDP and decreases in NDVI caused by rapid urbanization partly lead to the growth of AOD over the middle and lower reaches of the YRB. However, changes in precipitation and Population density alone may not be the main factors for the increasing AOD.

DOI:
10.1016/j.atmosenv.2018.07.034

ISSN:
1352-2310