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How Does an Improved Representation of Convection Affect Future Air Quality in the Community Earth System Model?

Presentation Date
Thursday, December 16, 2021 at 4:00pm
Convention Center - Poster Hall, D-F



In end-of-the-century climate simulations, fine particulate matter (PM2.5) which is hazardous to human health, is projected to decrease as aerosol emissions are reduced. However, future projections of climate which simulate anthropogenically emitted greenhouse gas emissions, such as RCP8.5, also produce changes in global precipitation frequency with warming, which can influence the removal of aerosol. Since present-day precipitation frequency is not well represented in conventional models, the impact of this change may be better captured by Earth system models with convective parameterizations replaced by high-resolution cloud resolving models (i.e., superparameterization). In order to isolate the effect of precipitation on aerosol removal (wet deposition), we fix aerosol emissions at present-day levels in the Community Atmosphere Model (CAM5) with both conventional and superparameterized convection. The effect of superparameterized convection on the removal and production four aerosol species (Black Carbon, Primary Organic Matter, Secondary Organic Aerosol, and Sulfate) is distinct from conventional representations under the 21st Century RCP8.5 scenario. In this study, we identify regions of worsening air quality as defined by the World Health Organization for longterm changes and extreme events (>25 μg/m3 for a 24-hour period).

Funding Program Area(s)