气候变化领域集成服务门户(CCPortal): Madden–Julian oscillation influence on sub-seasonal rainfall variability on the west of South America

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DOI	10.1007/s00382-019-05107-2
	Madden–Julian oscillation influence on sub-seasonal rainfall variability on the west of South America
	Recalde-Coronel G.C.; Zaitchik B.; Pan W.K.
发表日期	2020
ISSN	0930-7575
起始页码	2167
结束页码	2185
卷号	54
英文摘要	The Madden–Julian Oscillation (MJO) is the leading driver of intraseasonal rainfall variability in the global tropics. However, the influence of MJO on western tropical South America (WTSA) has not been a focus of research. This is not surprising since the MJO convective core becomes nondescript as it propagates across the eastern Pacific, such that its influence on the Pacific coast of tropical South America is not obvious in global analyses. In this study, we examine MJO impacts on subseasonal rainfall variability in the rainiest season for WTSA (February–April). In order to avoid confusion with El Niño Southern Oscillation (ENSO) signals, only ENSO-neutral years are included in the analysis. We found that the MJO convective core reemerges when it propagates onto land in WTSA, and that it is associated with subseasonal precipitation anomalies of 20–50% relative to climatology. The MJO signal is evident in the real-time multivariate MJO (RMM) index; however, the signal is clearer when a custom subseasonal index for the region based on WTSA outgoing longwave radiation is employed. Dynamically, the MJO influence is consistent with a modulation of the Pacific Ocean Walker Circulation descending branch, which is climatologically located in or near WTSA. Furthermore, MJO drives zonal and vertical motions on moisture and wind fields that influence precipitation in the region. We found that the timing of deep convection on subseasonal timescales captured by the regional index is consistent with a dominant role of the MJO convective core, rather than propagation of equatorial Rossby or Kelvin waves. However, there is evidence that equatorial Rossby waves that emerge over the tropical Atlantic Ocean also influence precipitation in WTSA on MJO timescales. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
英文关键词	Intraseasonal variability; Madden–Julian oscillation; Precipitation; South America; Western Amazon
语种	英语
scopus关键词	climate effect; El Nino-Southern Oscillation; equatorial dynamics; longwave radiation; Madden-Julian oscillation; precipitation (climatology); rainfall; seasonal variation; timescale; wind field; Amazonia; Atlantic Ocean; Atlantic Ocean (Tropical); Pacific Ocean; Pacific Ocean (East); South America
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/145586
作者单位	Department of Earth and Planetary Sciences, Johns Hopkins University, 327 Olin Hall, 3400 N. Charles Street, Baltimore, MD 21218, United States; Facultad de Ingeniería Marítima y Ciencias del Mar, Escuela Superior Politécnica del Litoral, Guayaquil, Ecuador; Duke Global Health Institute and Nicholas School of Environment, Duke University, Durham, NC, United States
推荐引用方式 GB/T 7714	Recalde-Coronel G.C.,Zaitchik B.,Pan W.K.. Madden–Julian oscillation influence on sub-seasonal rainfall variability on the west of South America[J],2020,54.
APA	Recalde-Coronel G.C.,Zaitchik B.,&Pan W.K..(2020).Madden–Julian oscillation influence on sub-seasonal rainfall variability on the west of South America.Climate Dynamics,54.
MLA	Recalde-Coronel G.C.,et al."Madden–Julian oscillation influence on sub-seasonal rainfall variability on the west of South America".Climate Dynamics 54(2020).