气候变化领域集成服务门户(CCPortal): Internal variability and external forcings in the ocean–atmosphere multidecadal oscillator over the North Atlantic

CCPortal

DOI	10.1007/s00382-020-05300-8
	Internal variability and external forcings in the ocean–atmosphere multidecadal oscillator over the North Atlantic
	Ribera P.; Ordoñez P.; Gallego D.; Peña-Ortiz C.
发表日期	2020
ISSN	0930-7575
起始页码	909
结束页码	923
卷号	55
英文摘要	In this paper, we generalize the concept of “external forcing” to include any mechanism that modulates the long-term evolution of a meteorological variable but is not directly related to the internal variability of the climate system. Applying this concept, the corresponding ‘external forcings’ are removed from several long record datasets of oceanic and atmospheric variables at the surface in the North Atlantic. We perform a multivariate analysis in the frequency domain over both the original data fields and the new ‘internal variability’ fields. This multivariate analysis is based on a MultiTaper Method-Singular Value Decomposition (MTM-SVD). It is noteworthy that, after the removal of the external forcings, there is an almost perfect alignment of the main multidecadal oscillatory band (f = 0.21 cycles/decade) with all the spectra of the analysed fields. This alignment was not observed before the external forcings were removed. Particularly striking is the case of the sea level pressure (SLP), which shows a notable variation in its oscillation period despite the fact that this variable has traditionally been considered to be unaffected, at global scale, by any external forcing. The external forcing in the SLP records is very probably caused by the scarcity of the observed data during the first hundred years of the record (most evident, during the earliest decades), by the spatial distribution of those observations and, possibly, by the assimilation model employed to build those long record datasets. When we analysed the relationship between the ocean and the atmosphere using this approach, we found strong evidence of a cyclic behaviour in which oceanic conditions modulate the atmospheric variability, with a lead time of up to about 10 years. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
英文关键词	Atlantic multidecadal oscillation (AMO); Blockings; External forcings; Internal climate variability; MTM-SVD; NAO; SST reanalyses; Twentieth century reanalysis
语种	英语
scopus关键词	air-sea interaction; atmosphere-ocean coupling; climate forcing; climate oscillation; climate variation; data assimilation; data set; decomposition analysis; multivariate analysis; temporal variation; Atlantic Ocean; Atlantic Ocean (North)
来源期刊	Climate Dynamics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/145404
作者单位	Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Seville, 41013, Spain; Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Mexico City, 04510, Mexico
推荐引用方式 GB/T 7714	Ribera P.,Ordoñez P.,Gallego D.,等. Internal variability and external forcings in the ocean–atmosphere multidecadal oscillator over the North Atlantic[J],2020,55.
APA	Ribera P.,Ordoñez P.,Gallego D.,&Peña-Ortiz C..(2020).Internal variability and external forcings in the ocean–atmosphere multidecadal oscillator over the North Atlantic.Climate Dynamics,55.
MLA	Ribera P.,et al."Internal variability and external forcings in the ocean–atmosphere multidecadal oscillator over the North Atlantic".Climate Dynamics 55(2020).