气候变化领域集成服务门户(CCPortal): Anthropogenic aerosols dominate forced multidecadal sahel precipitation change through distinct atmospheric and oceanic drivers

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DOI	10.1175/JCLI-D-19-0829.1
	Anthropogenic aerosols dominate forced multidecadal sahel precipitation change through distinct atmospheric and oceanic drivers
	HIRASAWA H.; KUSHNER P.J.; SIGMOND M.; FYFE J.; DESER C.
发表日期	2020
ISSN	0894-8755
起始页码	10187
结束页码	10204
卷号	33 期号:23
英文摘要	Sahel precipitation has undergone substantial multidecadal time scale changes during the twentieth century that have had severe impacts on the region's population. Using initial-condition large ensembles (LE) of coupled general circulation model (GCM) simulations from two institutions, forced multidecadal variability is found in which Sahel precipitation declines from the 1950s to 1970s and then recovers from the 1970s to 2000s. This forced variability has similar timing to, but considerably smaller magnitude than, observed Sahel precipitation variability. Isolating the response using single forcing simulations within the LEs reveals that anthropogenic aerosols (AA) are the primary driver of this forced variability. The roles of the direct-atmospheric and the ocean-mediated atmospheric responses toAAforcing are determined with the atmosphere-land GCM (AGCM) components of the LE coupled GCMs. The direct-atmospheric response arises from changes to aerosol and precursor emissions with unchanged oceanic boundary conditions while the ocean-mediated response arises from changes to AA-forced sea surface temperatures and sea ice concentrations diagnosed from the AAforced LE. In the AGCMs studied here, the direct-atmospheric response dominates the AA-forced 1970s 2 1950s Sahel drying. On the other hand, the 2000s 2 1970s wetting is mainly driven by the ocean-mediated effect, with some direct atmospheric contribution. Although the responses show differences, there is qualitative agreement between the AGCMs regarding the roles of the direct-atmospheric and ocean-mediated responses. Since these effects often compete and show nonlinearity, the model dependence of these effects and their role in the net aerosol-forced response of Sahel precipitation need to be carefully accounted for in future model analysis. © 2020 American Meteorological Society.
英文关键词	Aerosols; Precipitation (meteorology); Sea ice; Surface waters; Anthropogenic aerosols; Atmospheric contributions; Coupled general circulation models; Multi-decadal time scale; Multidecadal variability; Precipitation variability; Sea ice concentration; Sea surface temperature (SST); Oceanography; aerosol; air-sea interaction; anthropogenic source; climate forcing; climatology; decadal variation; general circulation model; marine atmosphere; monsoon; precipitation (climatology); Sahel [Sub-Saharan Africa]
语种	英语
来源期刊	Journal of Climate
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/170991
作者单位	Department of Physics, University of Toronto, Toronto, ON, Canada; Canadian Centre for Climate Change Modelling and Analysis, Environment and Climate Change Canada, Victoria, BC, Canada; National Center for Atmospheric Research, Boulder, CO, United States
推荐引用方式 GB/T 7714	HIRASAWA H.,KUSHNER P.J.,SIGMOND M.,et al. Anthropogenic aerosols dominate forced multidecadal sahel precipitation change through distinct atmospheric and oceanic drivers[J],2020,33(23).
APA	HIRASAWA H.,KUSHNER P.J.,SIGMOND M.,FYFE J.,&DESER C..(2020).Anthropogenic aerosols dominate forced multidecadal sahel precipitation change through distinct atmospheric and oceanic drivers.Journal of Climate,33(23).
MLA	HIRASAWA H.,et al."Anthropogenic aerosols dominate forced multidecadal sahel precipitation change through distinct atmospheric and oceanic drivers".Journal of Climate 33.23(2020).