Mid- to Late-Holocene Australian–Indonesian summer monsoon variability
Mid- to Late-Holocene Australian–Indonesian summer monsoon variability
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DOI：
10.1016/j.quascirev.2014.04.006
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发表时间：
2014-06
影响因子：
4
通讯作者：
S. Steinke;M. Mohtadi;M. Prange;V. Varma;D. Pittauerová;H. Fischer
中科院分区：
文献类型：
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作者：
S. Steinke;M. Mohtadi;M. Prange;V. Varma;D. Pittauerová;H. Fischer
澳大利亚-印度尼西亚季风对印度尼西亚人口稠密的岛屿的农业做法和生计具有支配性影响。然而，人们对影响印度尼西亚南部过去季风活动的因素知之甚少。在这里，我们提出了一个6000年的高分辨率记录的澳大利亚-印度尼西亚夏季风（AISM）降雨量的变化的基础上散装沉积物元素分析的沉积物档案检索近海西北松巴岛（印度尼西亚）。记录表明，较低的河流碎屑供应，因此较弱的AISM降雨6000年BP和3000年BP晚全新世相比。我们发现一个明显的转变，陆源沉积物供应在2800年BP左右，这表明在印度尼西亚南部的AISM从一个干燥的中全新世到一个潮湿的晚全新世的重组。在大约2800年BP降雨量的突然增加与一个盛大的太阳极小期相吻合。在印度尼西亚南部的降雨量增加，以响应太阳能最低是一致的气候模式模拟，提供了一个可能的解释的基本机制负责季风转变。我们的结论是，太阳活动的变化在季风降雨变率在几十年和更长的时间尺度上发挥了重要作用。轨道和太阳强迫的综合效应解释了过去6000年来AISM降雨时间演变的重要细节。相比之下，我们既没有发现火山强迫AISM变化的证据，也没有发现厄尔尼诺-南方涛动（ENSO）长期变化的控制。
The Australian–Indonesian monsoon has a governing influence on the agricultural practices and livelihood in the highly populated islands of Indonesia. However, little is known about the factors that have influenced past monsoon activity in southern Indonesia. Here, we present a ∼6000 years high-resolution record of Australian-Indonesian summer monsoon (AISM) rainfall variations based on bulk sediment element analysis in a sediment archive retrieved offshore northwest Sumba Island (Indonesia). The record suggests lower riverine detrital supply and hence weaker AISM rainfall between 6000 yr BP and ∼3000 yr BP compared to the Late Holocene. We find a distinct shift in terrigenous sediment supply at around 2800 yr BP indicating a reorganization of the AISM from a drier Mid Holocene to a wetter Late Holocene in southern Indonesia. The abrupt increase in rainfall at around 2800 yr BP coincides with a grand solar minimum. An increase in southern Indonesian rainfall in response to a solar minimum is consistent with climate model simulations that provide a possible explanation of the underlying mechanism responsible for the monsoonal shift. We conclude that variations in solar activity play a significant role in monsoonal rainfall variability at multi-decadal and longer timescales. The combined effect of orbital and solar forcing explains important details in the temporal evolution of AISM rainfall during the last 6000 years. By contrast, we find neither evidence for volcanic forcing of AISM variability nor for a control by long-term variations in the El Niño-Southern Oscillation (ENSO).