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DOI	10.1088/1748-9326/ab21e7
	Efficacy of black carbon aerosols: The role of shortwave cloud feedback
	Modak A.; Bala G.
发表日期	2019
ISSN	17489318
卷号	14 期号:8
英文摘要	Using idealized climate model simulations, we investigate the effectiveness of black carbon (BC) aerosols in warming the planet relative to CO2 forcing. We find that a 60-fold increase in the BC aerosol mixing ratio from the present-day levels leads to the same equilibrium global mean surface warming (∼4.1 K) as for a doubling of atmospheric CO2 concentration. However, the radiative forcing is larger (∼5.5 Wm-2) in the BC case relative to the doubled CO2 case (∼3.8 Wm-2) for the same surface warming indicating the efficacy (a metric for measuring the effectiveness) of BC aerosols to be less than CO2. The lower efficacy of BC aerosols is related to the differences in the shortwave (SW) cloud feedback: negative in the BC case but positive in the CO2 case. In the BC case, the negative SW cloud feedback is related to an increase in the tropical low clouds which is associated with a northward shift (∼7) of the Intertropical Convergence Zone (ITCZ). Further, we show that in the BC case fast precipitation suppression offsets the surface temperature mediated precipitation response and causes ∼8% net decline in the global mean precipitation. Our study suggests that a feedback between the location of ITCZ and the interhemispheric temperature could exist, and the consequent SW cloud feedback could be contributing to the lower efficacy of BC aerosols. Therefore, an improved representation of low clouds in climate models is likely the key to understand the global climate sensitivity to BC aerosols. © 2019 The Author(s). Published by IOP Publishing Ltd.
英文关键词	black carbon aerosols; climate feedback; climate sensitivity; cloud feedback; efficacy of forcings; hydrological cycle; ITCZ shift
语种	英语
scopus关键词	Aerosols; Atmospheric radiation; Carbon; Carbon dioxide; Fog; Black carbon aerosol; Climate feedbacks; Climate sensitivity; Cloud feedbacks; Forcings; Hydrological cycles; ITCZ shift; Climate models; aerosol; black carbon; carbon dioxide; climate modeling; cloud radiative forcing; global climate; hydrological cycle; intertropical convergence zone; precipitation (climatology); radiative forcing
来源期刊	Environmental Research Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/154441
作者单位	Center for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore, 560012, India
推荐引用方式 GB/T 7714	Modak A.,Bala G.. Efficacy of black carbon aerosols: The role of shortwave cloud feedback[J],2019,14(8).
APA	Modak A.,&Bala G..(2019).Efficacy of black carbon aerosols: The role of shortwave cloud feedback.Environmental Research Letters,14(8).
MLA	Modak A.,et al."Efficacy of black carbon aerosols: The role of shortwave cloud feedback".Environmental Research Letters 14.8(2019).