秸秆燃烧气溶胶的气象反馈及其棕碳吸光效应

Straw burning is a major source of biomass combustion in North China, significantly impacting air quality. Using the WRF-Chem model, we simulated the meteorological effects of aerosol emissions from straw burning in June 2013 and conducted a preliminary analysis of the light-absorbing properties of brown carbon (BrC) produced during straw burning. We conducted four sensitivity experiments, comparing the impact of BrC on light absorption with AERONET observations. Results showed that the model effectively captured variations in various parameters during the study period. Without considering BrC absorption, straw burning led to a reduction in surface shortwave radiation, causing a monthly average decrease of approximately 12.42 W·m^-2 in major agricultural regions. This resulted in near-surface cooling, warming above 2km, and reduced vertical diffusion, stabilizing the boundary layer. There was an overall increase in atmospheric pressure, coinciding with fire hotspot areas. Straw burning also induced strong near-surface wind divergence, hindering the horizontal transport of moist air masses from the ocean. Considering BrC absorption, the simulation of optical parameters significantly improved. The linear fit slope between simulated Absorption Aerosol Optical Depth (AAOD) and observed values increased from 0.47 to 0.53, and the slope of Aerosol Optical Depth (AOD) increased from 0.19 to 0.21. Biomass burning emissions of BrC had a notable impact on aerosol extinction, leading to increased AAOD and AOD to varying degrees.