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DOI	10.5194/acp-19-4235-2019
	Indications for a potential synchronization between the phase evolution of the Madden-Julian oscillation and the solar 27-day cycle
	Hoffmann C.G.; Von Savigny C.
发表日期	2019
ISSN	16807316
起始页码	4235
结束页码	4256
卷号	19 期号:7
英文摘要	The Madden-Julian oscillation (MJO) is a major source of intraseasonal variability in the troposphere. Recently, studies have indicated that also the solar 27-day variability could cause variability in the troposphere. Furthermore, it has been indicated that both sources could be linked, and particularly that the occurrence of strong MJO events could be modulated by the solar 27-day cycle. In this paper, we analyze whether the temporal evolution of the MJO phases could also be linked to the solar 27-day cycle. We basically count the occurrences of particular MJO phases as a function of time lag after the solar 27-day extrema in about 38 years of MJO data. Furthermore, we develop a quantification approach to measure the strength of such a possible relationship and use this to compare the behavior for different atmospheric conditions and different datasets, among others. The significance of the results is estimated based on different variants of the Monte Carlo approach, which are also compared. We find indications for a synchronization between the MJO phase evolution and the solar 27-day cycle, which are most notable under certain conditions: MJO events with a strength greater than 0.5, during the easterly phase of the quasi-biennial oscillation, and during boreal winter. The MJO appears to cycle through its eight phases within two solar 27-day cycles. The phase relation between the MJO and the solar variation appears to be such that the MJO predominantly transitions from phase 8 to 1 or from phase 4 and 5 during the solar 27-day minimum. These results strongly depend on the MJO index used such that the synchronization is most clearly seen when using univariate indices like the OLR-based MJO index (OMI) in the analysis but can hardly be seen with multivariate indices like the real-time multivariate MJO index (RMM). One possible explanation could be that the synchronization pattern is encoded particularly in the underlying outgoing longwave radiation (OLR) data. A weaker dependence of the results on the underlying solar proxy is also observed but not further investigated. Although we think that these initial indications are already worth noting, we do not claim to unambiguously prove this relationship in the present study, neither in a statistical nor in a causal sense. Instead, we challenge these initial findings ourselves in detail by varying underlying datasets and methods and critically discuss resulting open questions to lay a solid foundation for further research. © 2019 Copernicus GmbH. All rights reserved.
语种	英语
scopus关键词	longwave radiation; Madden-Julian oscillation; Monte Carlo analysis; quasi-biennial oscillation; solar cycle; temporal evolution; troposphere
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/144527
作者单位	Institute of Physics, University of Greifswald, Felix-Hausdorff-Str. 6, Greifswald, 17489, Germany
推荐引用方式 GB/T 7714	Hoffmann C.G.,Von Savigny C.. Indications for a potential synchronization between the phase evolution of the Madden-Julian oscillation and the solar 27-day cycle[J],2019,19(7).
APA	Hoffmann C.G.,&Von Savigny C..(2019).Indications for a potential synchronization between the phase evolution of the Madden-Julian oscillation and the solar 27-day cycle.Atmospheric Chemistry and Physics,19(7).
MLA	Hoffmann C.G.,et al."Indications for a potential synchronization between the phase evolution of the Madden-Julian oscillation and the solar 27-day cycle".Atmospheric Chemistry and Physics 19.7(2019).