气候变化领域集成服务门户(CCPortal): Characteristics of cut-off lows during the 2015–2017 drought in the Western Cape, South Africa

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DOI	10.1016/j.atmosres.2019.104772
	Characteristics of cut-off lows during the 2015–2017 drought in the Western Cape, South Africa
	Abba Omar S.; Abiodun B.J.
发表日期	2020
ISSN	0169-8095
卷号	235
英文摘要	Cut-Off Lows (COLs) are known for heavy rainfall in the Western Cape, but there is a dearth of information on COL rainfall characteristics over the Cape. To bridge this gap we analysed three types of datasets (observation, satellite and reanalysis) to study the characteristics of COLs that occurred in the vicinity of the Western Cape over 37 years (1981–2017) and applied a self-organising Map (SOM) to classify the COLs into groups based on their rainfall patterns. The results show about 10 COLs (per year) occur over the Western Cape and contribute about 11% of the annual rainfall in the cape but with a large inter-annual variability. In 2015 and 2016, the COLs occurred more frequently and contributed more rainfall than normal which reduced the drought severity. But, in 2017, the frequency and rainfall contribution of the COLs were below normal. Nevertheless, more COLs does not always mean higher COL rainfall as >45% of the COLs over the Western Cape produce little or no rainfall. The SOM results reveal that the spatial distribution of COL rainfall can be grouped into four major patterns. The first pattern indicates rainfall over the entire Western Cape, while the second shows little or no rainfall; the third and fourth patterns feature rainfall over the south-east coast and south-west coast, respectively. Wet COLs are associated with more southward transport of warm, moist tropical air into the Western Cape and greater contrasts between the warm and cold air masses compared to the dry COLs. © 2019 Elsevier B.V.
英文关键词	Cut-off lows; Drought; Western Cape rainfall
学科领域	Classification (of information); Drought; Annual rainfall; Cut-off low; Drought severity; Interannual variability; Rainfall characteristics; Rainfall contributions; Rainfall patterns; Western Cape , South Africa; Rain; air mass; annual variation; data set; drought; rainfall; satellite data; spatial distribution; South Africa; Western Cape
语种	英语
scopus关键词	Classification (of information); Drought; Annual rainfall; Cut-off low; Drought severity; Interannual variability; Rainfall characteristics; Rainfall contributions; Rainfall patterns; Western Cape , South Africa; Rain; air mass; annual variation; data set; drought; rainfall; satellite data; spatial distribution; South Africa; Western Cape
来源期刊	Atmospheric Research
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/120495
作者单位	Climate System Analysis Group, Department of Environmental and Geographical Science, University of Cape Town, Cape Town, South Africa
推荐引用方式 GB/T 7714	Abba Omar S.,Abiodun B.J.. Characteristics of cut-off lows during the 2015–2017 drought in the Western Cape, South Africa[J],2020,235.
APA	Abba Omar S.,&Abiodun B.J..(2020).Characteristics of cut-off lows during the 2015–2017 drought in the Western Cape, South Africa.Atmospheric Research,235.
MLA	Abba Omar S.,et al."Characteristics of cut-off lows during the 2015–2017 drought in the Western Cape, South Africa".Atmospheric Research 235(2020).