DOI: 10.1002/joc.5668
论文题名: The role of regional circulation features in regulating El Niño climate impacts over southern Africa: A comparison of the 2015/2016 drought with previous events
作者: Blamey R.C. ; Kolusu S.R. ; Mahlalela P. ; Todd M.C. ; Reason C.J.C.
刊名: International Journal of Climatology
ISSN: 8998418
出版年: 2018
卷: 38, 期: 11 起始页码: 4276
结束页码: 4295
语种: 英语
英文关键词: Angola Low
; Botswana High
; droughts
; El Niño
; southern Africa
; tropical–extra-tropical connections
Scopus关键词: Digital storage
; Drought
; Moisture
; Angola Low
; Botswana
; Convective precipitation
; Moisture convergence
; Regional circulation
; South Indian Ocean
; Southern Africa
; Standardized precipitation index
; Rain
; atmospheric moisture
; climate effect
; comparative study
; drought
; El Nino
; precipitation (climatology)
; rainfall
; Angola
; Botswana
英文摘要: Extremely dry conditions were experienced across most of southern Africa during the austral summer (October–March) of 2015/2016, associated with one of the strongest observed El Niño events in the Pacific. Dry conditions peaked in the early austral summer months (October–December) producing the most intense drought in the 116-year historical record, as measured by the intensity of the standardized precipitation index across all spatial scales up to the sub-continental. We estimate the return period of this extreme early summer drought to be greater than 200 years. The interior and eastern parts of South Africa were particularly hard-hit with station data showing rainfall totals being at their lowest since at least 1950. The early summer dry conditions make the 2015/2016 event atypical compared to past El Niño events of similar magnitude. We find that key regional circulation patterns, influenced by planetary-scale processes, play an important role in modulating the spatial and temporal evolution of the summer rainfall during these El Niño events. Specifically, (a) the Angola Low and the South Indian Ocean High, two dominant low-level circulation features that drive moisture convergence to support convective precipitation in the region, were anomalously weakened in early austral summer of 2015/2016 resulting in less moisture being transported over the continent, and (b) the mid-level Botswana High was stronger than in previous El Niño years further producing unfavourable conditions for rainfall through stronger subsidence in the mid- to upper levels over southern Africa. © 2018 Royal Meteorological Society Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/116802
Appears in Collections: 气候减缓与适应
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作者单位: Department of Oceanography, University of Cape Town, Cape Town, South Africa; Department of Geography, University of Sussex, Sussex, United Kingdom
Recommended Citation:
Blamey R.C.,Kolusu S.R.,Mahlalela P.,et al. The role of regional circulation features in regulating El Niño climate impacts over southern Africa: A comparison of the 2015/2016 drought with previous events[J]. International Journal of Climatology,2018-01-01,38(11)