Wintertime temperature response to anthropogenic aerosols emissions over East Asia in the 20th century

Abstract:

Aerosol emission by the anthropogenic source has increased in the 20th century and the effects on climate have received much attention for understanding of historical climate change. Aerosols contribute to change solar radiation at the surface directly and indirectly enhance radiative effect through cloud properties changes, altering surface climate and large-scale atmospheric circulation as well. In East Asia, as anthropogenic emissions increased sharply in industrialized areas, many studies have shown the effect of aerosols on East Asian summer monsoon related to changes in land sea thermal contrast, while studies on the wintertime climate response are few. Climatologically he East Asian winter monsoon is controlled by the intensification of Siberian high and the deepening of Aleutian low which are attributed to higher east-west surface pressure gradient and strong northerly wind. We are interested in the wintertime surface climate change affected by past aerosol emissions.
This study uses historical simulations of seven ensemble members by the HadGEM2-AO developed by the UK Met Office. Contrasting with the historical runs, the fixed aerosol experiments are performed where aerosol emissions are held fixed at 1860 levels.
As the emissions increase, simulations shows decrease in wintertime land surface temperature, increase in MSLP over the land and northerly wind speeds. In order to understand the circulation changes, we analyze direct and indirect aerosol influences and the results are presented.

Acknowledgement: This research is supported by a project, “NIMR-2012-B-2(Development and Application of Methodology for Climate Change Prediction)”.