A high-resolution record of Holocene rainfall variations from the western Chinese Loess Plateau: antiphase behaviour of the African/Indian and East Asian summer monsoons
A high-resolution record of Holocene rainfall variations from the western Chinese Loess Plateau: antiphase behaviour of the African/Indian and East Asian summer monsoons
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DOI：
10.1191/0959683606hl929rp
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发表时间：
2006-04
期刊：
影响因子：
--
通讯作者：
B. Maher;Mengyu Hu
中科院分区：
文献类型：
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作者：
B. Maher;Mengyu Hu
热带季风是将热量和水分转移到高纬度地区的关键机制。在这里，我们提出了一个高分辨率，陆地代理夏季风记录东南亚季风，从中国西部黄土高原的快速积累全新世黄土/土壤序列。我们使用磁性和碎屑粒度代理，使全新世降雨量的定量估计，并确定冬季风强度的变化。我们的记录揭示了周期性的千年和多千年降雨量的变化。与西北非洲/西南亚季风记录，一个短暂的干旱间隔在-12.5至11.5 ka BP（新仙女木）和随后的夏季风加强记录。6 kaBP时，东南亚夏季风减弱，西北非洲/西南亚季风增强;-5kaBP时，东南亚夏季风增强，西北非洲/西南亚季风变干。这些反相季风关系可能反映了海表温度变化和太阳强迫之间的竞争。-9kaBP以来，东南亚冬季风强度增强，与夏季风强度的相位关系有所不同。在-2.25kaBP之后，两个气候指标都显示出极端的气候不稳定性。
Tropical monsoons are key mechanisms for transfer of heat and moisture to higher latitudes. Here we present a high-resolution, terrestrial proxy summer monsoon record for the southeast Asian monsoon, from a rapidly accumulating Holocene loess/soil sequence in the western Chinese Loess Plateau. We use magnetic and clastic grain size proxies to make quantitative estimates of Holocene rainfall and identify variations in winter monsoon intensity. Our record reveals cyclical millennial and multimillennial rainfall changes. As with the northwest African/southwest Asian monsoon records, a short arid interval at - 12.5 to 11.5 ka BP (the Younger Dryas) and subsequent summer monsoon intensification are recorded. However, at 6 ka BP, the southeast Asian summer monsoon weakened, when the northwest African/ southwest Asian monsoons strengthened, and then, from - 5 ka BP, intensified, when northwest Africa/ southwest Asia became dry. These antiphase monsoonal relationships may reflect competition between sea surface temperature changes and solar forcing. The intensity of the southeast Asian winter monsoon intensified from - 9 ka BP onwards, varying in its phase relationships with summer monsoon intensity. After - 2.25 ka BP, extreme climatic instability is indicated by both climate proxies.