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DOI	10.5194/acp-22-1739-2022
	Limitations of assuming internal mixing between different aerosol species: a case study with sulfate geoengineering simulations
	Visioni, Daniele; Tilmes, Simone; Bardeen, Charles; Mills, Michael; MacMartin, Douglas G.; Kravitz, Ben; Richter, Jadwiga H.
发表日期	2022
ISSN	1680-7316
EISSN	1680-7324
起始页码	1739
结束页码	1756
卷号	22 期号:3 页码:18
英文摘要	Simulating the complex aerosol microphysical processes in a comprehensive Earth system model can be very computationally intensive; therefore many models utilize a modal approach, where aerosol size distributions are represented by observation-derived lognormal functions, and internal mixing between different aerosol species within an aerosol mode is often assumed. This approach has been shown to yield satisfactory results across a large array of applications, but there may be cases where the simplification in this approach may produce some shortcomings. In this work we show specific conditions under which the current approximations used in some modal approaches might yield incorrect answers. Using results from the Community Earth System Model v1 (CESM1) Geoengineering Large Ensemble (GLENS) project, we analyze the effects in the troposphere of a continuous increasing load of sulfate aerosols in the stratosphere, with the aim of counteracting the surface warming produced by non-mitigated increasing greenhouse gas (GHG) concentrations between 2020-2100. We show that the simulated results pertaining to the evolution of sea salt and dust aerosols in the upper troposphere are not realistic due to internal mixing assumptions in the modal aerosol treatment, which in this case reduces the size, and thus the settling velocities, of those particles and ultimately changes their mixing ratio below the tropopause. The unnatural increase of these aerosol species affects, in turn, the simulation of upper tropospheric ice formation, resulting in an increase in ice clouds that is not due to any meaningful physical mechanisms. While we show that this does not significantly affect the overall results of the simulations, we point to some areas where results should be interpreted with care in modeling simulations using similar approximations: in particular, in the evolution of upper tropospheric clouds when large amounts of sulfate are present in the stratosphere, as after a large explosive volcanic eruption or in similar stratospheric aerosol injection cases. Finally, we suggest that this can be avoided if sulfate aerosols in the coarse mode, the predominant species in these situations, are treated separately from other aerosol species in the model.
学科领域	Environmental Sciences; Meteorology & Atmospheric Sciences
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences
WOS记录号	WOS:000758040000001
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/273272
作者单位	Cornell University; National Center Atmospheric Research (NCAR) - USA; Indiana University System; Indiana University Bloomington; United States Department of Energy (DOE); Pacific Northwest National Laboratory; National Center Atmospheric Research (NCAR) - USA
推荐引用方式 GB/T 7714	Visioni, Daniele,Tilmes, Simone,Bardeen, Charles,et al. Limitations of assuming internal mixing between different aerosol species: a case study with sulfate geoengineering simulations[J],2022,22(3):18.
APA	Visioni, Daniele.,Tilmes, Simone.,Bardeen, Charles.,Mills, Michael.,MacMartin, Douglas G..,...&Richter, Jadwiga H..(2022).Limitations of assuming internal mixing between different aerosol species: a case study with sulfate geoengineering simulations.ATMOSPHERIC CHEMISTRY AND PHYSICS,22(3),18.
MLA	Visioni, Daniele,et al."Limitations of assuming internal mixing between different aerosol species: a case study with sulfate geoengineering simulations".ATMOSPHERIC CHEMISTRY AND PHYSICS 22.3(2022):18.