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Aerosols emitted from biomass burning affect human health and climate, both regionally and globally. The magnitude of these impacts is altered by the biomass burning plume injection height (BB-PIH). However, these alterations are not well-understood on a global scale. We present the novel implementation of BB-PIH in global simulations with an atmospheric chemistry model (GEOS-Chem) coupled with detailed TwO-Moment Aerosol Sectional (TOMAS) microphysics. We conduct BB-PIH simulations under three scenarios: (a) All smoke is well-mixed into the boundary layer, and (b) and (c) smoke injection height is based on Global Fire Assimilation System (GFAS) plume heights. Elevating BB-PIH increases the simulated global-mean aerosol optical depth (10%) despite a global-mean decrease (1%) in near-surface PM2.5. Increasing the tropospheric column mass yields enhanced cooling by the global-mean clear-sky biomass burning direct radiative effect. However, increasing BB-PIH places more smoke above clouds in some regions; thus, the all-sky biomass burning direct radiative effect has weaker cooling in these regions as a result of increasing the BB-PIH. Elevating the BB-PIH increases the simulated global-mean cloud condensation nuclei concentrations at low-cloud altitudes, strengthening the global-mean cooling of the biomass burning aerosol indirect effect with a more than doubling over marine areas. Elevating BB-PIH also generally improves model agreement with the satellite-retrieved total and smoke extinction coefficient profiles. Our 2-year global simulations with new BB-PIH capability enable understanding of the global-scale impacts of BB-PIH modeling on simulated air-quality and radiative effects, going beyond the current understanding limited to specific biomass burning regions and seasons. Plain Language Summary Biomass burning includes wildfires, prescribed burns, and agricultural burns; and is an important source of aerosol particles in the atmosphere. These aerosol particles are important for climate and human health. Our work contributes to understanding the global and interannual impacts of changing the height of these particles in the atmosphere. We ran multiple global atmospheric chemistry model simulations with each simulation having different heights for aerosol particles from biomass burning. Simulations with a higher average emission height had more smoke aerosol particles in the entire atmosphere, resulting in an increase in the cooling radiative impact of biomass burning compared to simulations with a lower average emission height. We found that simulations with a higher average emission height for biomass burning aerosols had slightly better agreement with satellite observations relative to lower heights. This study shows the importance of biomass burning aerosol emission height on Earth's global air quality and climate.

来源平台：JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS