Precipitation variability in the winter rainfall zone of South Africa during the last 1400 yr linked to the austral westerlies
Precipitation variability in the winter rainfall zone of South Africa during the last 1400 yr linked to the austral westerlies
复制标题
过去 1400 年南非冬季降雨区的降水变化与南方西风带有关
DOI：
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
D. Dixon
中科院分区：
文献类型：
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作者：
J. Stager;P. Mayewski;J. White;B. Chase;F. Neumann;M. Meadows;Christiaan King;D. Dixon
南半球西风带强烈地影响着南温带的降水和海洋环流，对文化和生态系统有着重要的影响。全球气候模型预测随着未来变暖，南方西风带将向极地退缩，但可能测试这些模型的现有古气候记录仅限于南美洲和新西兰，彼此之间并不完全一致，并且可能受到其他气候因素的影响。在这里，我们提出了第一个高分辨率的硅藻和沉积记录从南非的冬季降雨区，在过去的1400年中，西风带的赤道边缘的降水。推断的降雨量相对较高，约为1400-1200 cal/yr BP，下降至约950 cal/yr BP，并在小冰期显著上升，脉冲集中在约600、530、470、330、200、90和20 cal/yr BP。南极冰芯化学的同步波动强烈表明，这些变化与西风带的变化有关。在潮湿的时期，西风带向赤道的漂移可能通过限制非洲尖端周围的海洋流动而影响大西洋纬向翻转环流。来自南美洲、新西兰和南非的记录在某些方面存在明显的不一致性，这警告人们不要将单一记录简单地应用于整个南半球。尽管如此，这些研究结果在一般情况下支持模式预测的增加干燥在南部冬季降雨区与未来变暖。
The austral westerlies strongly influence precipitation and ocean circulation in the southern temperate zone, with important consequences for cultures and ecosystems. Global climate models anticipate poleward retreat of the austral westerlies with future warming, but the available paleoclimate records that might test these models have been limited to South America and New Zealand, are not fully consistent with each other and may be complicated by influences from other climatic factors. Here we present the first high-resolution diatom and sedimentological records from the winter rainfall region of South Africa, representing precipitation in the equatorward margin of the westerly wind belt during the last 1400 yr. Inferred rainfall was relatively high ∼1400–1200 cal yr BP, decreased until ∼950 cal yr BP, and rose notably through the Little Ice Age with pulses centred on ∼600, 530, 470, 330, 200, 90, and 20 cal yr BP. Synchronous fluctuations in Antarctic ice core chemistry strongly suggest that these variations were linked to changes in the westerlies. Equatorward drift of the westerlies during the wet periods may have influenced Atlantic meridional overturning circulation by restricting marine flow around the tip of Africa. Apparent inconsistencies among some aspects of records from South America, New Zealand and South Africa warn against the simplistic application of single records to the Southern Hemisphere as a whole. Nonetheless, these findings in general do support model projections of increasing aridity in the austral winter rainfall zones with future warming.
影响因子：
64.8
作者：
Biastoch, A.;Boening, C. W.;Lutjeharms, J. R. E.
通讯作者：
Lutjeharms, J. R. E.
影响因子：
64.8
作者：
Biastoch, A.;Boening, C. W.;Lutjeharms, J. R. E.
通讯作者：
Lutjeharms, J. R. E.
影响因子：
18.3
作者：
Lamy, Frank;Kilian, Rolf;Steinke, Tatjana
通讯作者：
Steinke, Tatjana