干旱区生态环境知识资源中心(Arid): Intraseasonal descriptors and extremes in South African rainfall. Part II: Summer teleconnections across multiple timescales

Arid

DOI	10.1002/joc.8059
	Intraseasonal descriptors and extremes in South African rainfall. Part II: Summer teleconnections across multiple timescales
	Ullah, Asmat; Pohl, Benjamin; Pergaud, Julien; Dieppois, Bastien; Rouault, Mathieu
通讯作者	Ullah, A
来源期刊	INTERNATIONAL JOURNAL OF CLIMATOLOGY
ISSN	0899-8418
EISSN	1097-0088
出版年	2023
卷号	43 期号:8 页码:3799-3827
英文摘要	Extreme events contribute significantly to rainfall variability in semi-arid regions like South Africa. Here, following the definition of a novel typology of rainfall extremes, disentangling large- and small-scale events in Part I, we use quality-controlled observational databases in South Africa, the ERA5 reanalysis and satellite estimates TRMM-3B42 to examine the relationship between these two types of rainfall extremes and different modes of climate variability at various timescales. At low frequencies, rainfall extremes are assessed at interannual (IV: 2-8 years) and quasi-decadal (QDV: 8-13 years) timescales, which are primarily associated with the El Nino-Southern Oscillation (ENSO) and the Interdecadal Pacific Oscillation (IPO), respectively. At subseasonal timescales, the typology of rainfall extremes is analysed depending on the synoptic configurations, as inferred by seven convective regimes including tropical temperate troughs (TTTs: 3-7 days), and the intraseasonal variability associated with the Madden-Julien Oscillation (MJO: 30-60 days). At the IV timescale, the occurrence of large-scale extremes is substantially higher during its wet phases thereby suggesting a 400% rise in the occurrence of large-scale extremes as compared to its dry phases. At the QDV timescale, variability mostly relates to the modulation of small-scale extremes during its wet phases. Teleconnections with global sea surface temperature (SST) confirm that La Nina conditions favour overall wet conditions and extremes in South Africa. The numbers of large-scale extremes are consistently related to warmer SSTs in the North Atlantic, while their link with warmer Indian and tropical South Atlantic oceans is found to be statistically independent of the state of ENSO. At the subseasonal timescales, large-scale extremes largely occur during three out of the seven convective regimes identified in the southern African region whereas small-scale extremes are nearly equiprobable during all convective regimes. The occurrence of large-scale extremes during continent-rooted TTT is further enhanced during the locally wet phases of the MJO and is symmetrically weakened during its dry phases.
英文关键词	atmospheric convection El Nino-Southern Oscillation Interdecadal Pacific Oscillation large-scale and small-scale extremes Madden-Julien Oscillation rainfall South Africa tropical temperate troughs
类型	Article
语种	英语
开放获取类型	Green Published, hybrid
收录类别	SCI-E
WOS记录号	WOS:000956088800001
WOS关键词	MADDEN-JULIAN-OSCILLATION ; TROPICAL-TEMPERATE TROUGHS ; INTERDECADAL VARIABILITY ; PROJECTED CHANGES ; PRECIPITATION ; CLIMATE ; ENSO ; IMPACTS ; EVENTS ; SEASON
WOS类目	Meteorology & Atmospheric Sciences
WOS研究方向	Meteorology & Atmospheric Sciences
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/396971
推荐引用方式 GB/T 7714	Ullah, Asmat,Pohl, Benjamin,Pergaud, Julien,et al. Intraseasonal descriptors and extremes in South African rainfall. Part II: Summer teleconnections across multiple timescales[J],2023,43(8):3799-3827.
APA	Ullah, Asmat,Pohl, Benjamin,Pergaud, Julien,Dieppois, Bastien,&Rouault, Mathieu.(2023).Intraseasonal descriptors and extremes in South African rainfall. Part II: Summer teleconnections across multiple timescales.INTERNATIONAL JOURNAL OF CLIMATOLOGY,43(8),3799-3827.
MLA	Ullah, Asmat,et al."Intraseasonal descriptors and extremes in South African rainfall. Part II: Summer teleconnections across multiple timescales".INTERNATIONAL JOURNAL OF CLIMATOLOGY 43.8(2023):3799-3827.