Aerosol radiative impact on surface ozone during a heavy dust and biomass burning event over South Asia

摘要

Aerosols can modify both short and long term weather patterns by impacting the radiation budget of Earth. Numerical simulations were performed to understand the direct effect of aerosol on radiation during an elevated dust and black carbon (BC) concentration period over south Asia. The impact of the aerosol (dust and BC separately) direct effect on meteorology and air quality (focusing on surface ozone) was assessed using a fully coupled chemical transport model (WRF-Chem). The model simulates the elevated dust and BC concentration plume well qualitatively. Our results show that elevated BC concentration can reduce surface temperature up to 2 K. Incoming short wave flux at the surface and the boundary layer height reduced up to 70% due to the radiative impact of BC. 'This reduction in boundary layer height further increases the BC concentration at the source region. The radiative impact of dust on meteorological parameters are found to be less compared to BC at the surface level. The model simulates realistic surface ozone concentration using HTAP emission inventory. Results reveal that the presence of biomass burning can increase the surface ozone concentration by up to 40%. The radiative impact of BC can reduce the surface ozone concentration by more than 30% by altering the photolysis frequencies.