气候变化领域集成服务门户(CCPortal): Teleconnection processes linking the intensity of the atlantic multidecadal variability to the climate impacts over Europe in boreal winter

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DOI	10.1175/JCLI-D-19-0428.1
	Teleconnection processes linking the intensity of the atlantic multidecadal variability to the climate impacts over Europe in boreal winter
	Qasmi S.; Cassou C.; Boé J.
发表日期	2020
ISSN	0894-8755
起始页码	2681
结束页码	2700
卷号	33 期号:7
英文摘要	The response of the European climate to the Atlantic multidecadal variability (AMV) remains difficult to isolate in observations because of the presence of strong internal variability and anthropogenically forced signals. Using model sensitivity experiments proposed within the CMIP6/Decadal Climate Prediction Project Component C (DCPP-C) framework, the wintertime AMV-Europe teleconnection is here investigated in large ensembles of pacemaker-type simulations conducted with the CNRM-CM5 global circulation model. To evaluate the sensitivity of the model response to the AMV amplitude, twin experiments with the AMV forcing pattern multiplied by 2 and 3 (2xAMV and 3xAMV, respectively) are performed in complement to the reference ensemble (1xAMV). Based on a flow analog method, we show that the AMV-forced atmospheric circulation tends to cool down the European continent, whereas the residual signal, mostly including thermodynamical processes, contributes to warming. In 1xAMV, both terms cancel each other, explaining the overall weak AMV-forced atmospheric signal. In 2xAMV and 3xAMV, the thermodynamical contribution overcomes the dynamical cooling and is responsible for milder and wetter conditions found at large scale over Europe. The thermodynamical term includes the advection of warmer and more humid oceanic air penetrating inland and the modification of surface radiative fluxes linked to both altered cloudiness and snow-cover reduction acting as a positive feedback with the AMV amplitude. The dynamical anomalous circulation combines 1) a remote response to enhanced diabatic heating acting as a Rossby wave source in the western tropical Atlantic and 2) a local response associated with warmer SST over the subpolar gyre favoring an anomalous high. The extratropical influence is reinforced by polar amplification due to sea ice melting in all the subarctic seas. The weight between the tropical-extratropical processes and associated feedbacks is speculated to partly explain the nonlinear sensibility of the response to the AMV forcing amplitude, challenging thus the use of the so-called pattern-scaling technique to evaluate teleconnectivity and related impacts associated with decadal variability. © 2020 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).
英文关键词	Atmospheric movements; Climatology; Mechanical waves; Oceanography; Sea ice; Snow; Tropics; Atmospheric circulation; Global circulation model; Internal variability; Multidecadal variability; Polar amplifications; Surface radiative flux; Thermodynamical process; Western tropical atlantic; Climate models; air-sea interaction; analog model; Atlantic Multidecadal Oscillation; climate effect; climate forcing; climate modeling; decadal variation; diabatic process; Rossby wave; teleconnection; thermodynamics; Europe
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/171365
作者单位	CECI, Université de Toulouse, CNRS, CERFACS, Toulouse, France
推荐引用方式 GB/T 7714	Qasmi S.,Cassou C.,Boé J.. Teleconnection processes linking the intensity of the atlantic multidecadal variability to the climate impacts over Europe in boreal winter[J],2020,33(7).
APA	Qasmi S.,Cassou C.,&Boé J..(2020).Teleconnection processes linking the intensity of the atlantic multidecadal variability to the climate impacts over Europe in boreal winter.Journal of Climate,33(7).
MLA	Qasmi S.,et al."Teleconnection processes linking the intensity of the atlantic multidecadal variability to the climate impacts over Europe in boreal winter".Journal of Climate 33.7(2020).