DOI: 10.5194/cp-9-2347-2013
Scopus记录号: 2-s2.0-84886430342
论文题名: Holocene climate variability in the winter rainfall zone of South Africa
作者: Weldeab S. ; Stuut J.-B.W. ; Schneider R.R. ; Siebel W.
刊名: Climate of the Past
ISSN: 18149324
出版年: 2013
卷: 9, 期: 5 起始页码: 2347
结束页码: 2364
语种: 英语
Scopus关键词: aridification
; climate variation
; coastal water
; grain size
; Holocene
; proxy climate record
; rainfall
; sediment analysis
; upwelling
; Orange River
; South Africa
英文摘要: We established a multi-proxy time series comprising analyses of major elements in bulk sediments, Sr and Nd isotopes, grain size of terrigenous fraction, and δ18O and δ13°C in tests of Neogloboquadrina pachyderma (sinistral) from a marine sediment sequence recovered off the Orange River. The records reveal coherent patterns of variability that reflect changes in wind strength, precipitation over the river catchments, and upwelling of cold and nutrient-rich coastal waters off western South Africa. The wettest episode of the Holocene in the winter rainfall zone (WRZ) of South Africa occurred during the "Little Ice Age" (700-100 cal years BP) most likely in response to a northward shift of the austral westerlies. Wet phases and strengthened coastal water upwellings are companied by a decrease of Agulhas water leakage into the South Atlantic and a reduced dust incursion over Antarctica, as indicated in previous studies. A continuous aridification trend in the WRZ and a weakening of the southern Benguela Upwelling System (BUS) between 9000 and 5500 cal years BP parallel with increase of dust deposition over Antarctica and an enhanced leakage of warm Agulhas water into the eastern South Atlantic. The temporal relationship between precipitation changes in the WRZ, the thermal state of the coastal surface water, and leakage of warm water in the South Atlantic, and variation of dust incursion over Antarctica suggests a causal link that most likely was related to latitudinal shifts of the Southern Hemisphere westerlies. Our results of the mid-Holocene time interval may serve as an analogue to a possible long-term consequence of the current and future southward shift of the westerlies. Furthermore, warming of the coastal surface water as a result of warm Agulhas water incursion into the southern BUS may affect coastal fog formation. © 2013 Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/49360
Appears in Collections: 气候变化与战略
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Recommended Citation:
Weldeab S.,Stuut J.-B.W.,Schneider R.R.,et al. Holocene climate variability in the winter rainfall zone of South Africa[J]. Climate of the Past,2013-01-01,9(5)