Effects of feedbacks on meteorological and chemistry - Take the heavily polluted China region during the period of APEC supernormal emission reduction as an example

The energy of the Earth's atmospheric system is almost entirely from solar radiation. Since aerosols scatter and absorb sunlight, they exert important influences on atmospheric radiation, which in turn alters the weather or climate, especially in heavily polluted areas such as China. The weather or climate system is an intricate system in which various processes are interrelated. This presentation selects a heavily polluted China region during a supernormal emission reduction period to assess the influence of aerosol feedback on local weather. Numerical Sensitivity numerical investigations using WRF-Chem models subject to "feedback" and "no feedback" scenarios were conducted. The results reveal that: (1) the aerosol feedback increases the concentrations of air pollutants such as O3, PM2.5 and SO2, resulting in declining temperature, surface short-wave radiation, boundary-layer height, wind speed and wind direction and increasing surface pressure. The aerosol feedback is mainly featured changes in atmospheric levels of particulate matter and the intensity of solar radiation. (2) It was found that the aerosol feedback affected the local air pollution whereas the changes in meteorology were attributed to both PM pollution and background weather pattern. Hence, the changes in meteorological fields associated aerosol feedback illustrated a larger and varied spatial and temporal scale. (3) The aerosol feedback effects on meteorological fields have different spatial-temporal scales between Southern and Northern China. In Northern China, such influence has a relatively larger spatial-temporal scale, but in Southern China, the aerosol feedback effect has a relatively small and short spatial-temporal scale.