DOI: 10.1007/s00382-012-1589-4
Scopus记录号: 2-s2.0-84884700014
论文题名: Cloud bands over southern Africa: Seasonality, contribution to rainfall variability and modulation by the MJO
作者: Hart N.C.G. ; Reason C.J.C. ; Fauchereau N.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2013
卷: 41, 期: 2017-05-06 起始页码: 1199
结束页码: 1212
语种: 英语
英文关键词: Cloud bands
; Intraseasonal
; Rainfall
; South Africa
; TTT
英文摘要: Tropical-extratropical cloud band systems over southern Africa, known as tropical temperate troughs (TTTs), are known to contribute substantially to South African summer rainfall. This study performs a comprehensive assessment of the seasonal cycle and rainfall contribution of TTTs by using a novel object-based strategy that explicitly tracks these systems for their full life cycle. The methodology incorporates a simple assignment of station rainfall data to each event, thereby creating a database containing detailed rainfall characteristics for each TTT. This is used to explore the importance of TTTs for rain days and climatological rainfall totals in October-March. Average contributions range from 30 to 60 % with substantial spatial heterogeneity observed. TTT rainfall contributions over the Highveld and eastern escarpment are lower than expected. A short analysis of TTT rainfall variability indicates TTTs provide substantial, but not dominant, intraseasonal and interannual variability in station rainfall totals. TTTs are however responsible for a high proportion of heavy rainfall days. Of 52 extreme rainfall events in the 1979-1999 period, 30 are associated with these tropical-extratropical interactions. Cut-off lows were included in the evolution of 6 of these TTTs. The study concludes with an analysis of the question: does the Madden-Julian Oscillation influence the intensity of TTT rainfall over South Africa? Results suggest a weak but significant suppression (enhancement) of intensity during phase 1(6). © 2012 Springer-Verlag Berlin Heidelberg. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/54789
Appears in Collections: 过去全球变化的重建
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作者单位: Dept. Oceanography, MaRe Institute, University of Cape Town, Cape Town, South Africa; NIWA, Auckland, New Zealand
Recommended Citation:
Hart N.C.G.,Reason C.J.C.,Fauchereau N.. Cloud bands over southern Africa: Seasonality, contribution to rainfall variability and modulation by the MJO[J]. Climate Dynamics,2013-01-01,41(2017-05-06)