Prolonged monsoon droughts and links to Indo-Pacific warm pool: A Holocene record from Lonar Lake, central India
Prolonged monsoon droughts and links to Indo-Pacific warm pool: A Holocene record from Lonar Lake, central India
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DOI：
10.1016/j.epsl.2014.01.043
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发表时间：
2014-04-01
影响因子：
5.3
通讯作者：
Stebich, M.
中科院分区：
文献类型：
--
作者：
Prasad, Sushma;Anoop, A.;Stebich, M.
对全球气候变化在变暖情况下对区域影响的担忧突显了我们对印度夏季风(ISM，也称为印度洋夏季风)的理解存在差距，以及缺乏来自印度中部核心季风区(CMZ)的长期古气候数据。在这里，我们提出了第一个高分辨率，测年良好，从印度中部洛纳尔湖抬升的10米长的沉积岩芯中重建全新世古气候。结果表明，尽管CMZ早期全新世季风爆发与其他ISM记录相似，但LONAR资料显示，在4.6-3.9和2-0.6卡卡之间有两次持续的干旱(PD，较弱季风的数十年至百年周期)。将我们的记录与其他受ISM影响的地点的现有数据进行比较，结果表明，这些PD的影响在整个ISM领域都有不同程度的观察到，并且与较高的太阳辐射间隔相吻合。我们证明：(I)印度-太平洋暖池(IPWP)的区域变暖通过改变经向翻转环流和异常Walker环流的位置，在引起ISM PD方面发挥了重要作用；(Ii)厄尔尼诺-南方涛动(ENSO)等条件对ISM的长期影响仅开始约2ka BP，并与IPWP南部变暖一致；(Iii)印度中部的第一批定居点恰逢第一次PD的开始，农业人口在两个PD之间蓬勃发展，突显了自然气候变异性和PD作为影响人类住区的主要环境因素的重要性。(C)2014爱思唯尔B.V.保留所有权利。
Concerns about the regional impact of global climate change in a warming scenario have highlighted the gaps in our understanding of the Indian Summer Monsoon (ISM, also referred to as the Indian Ocean summer monsoon) and the absence of long term palaeoclimate data from the central Indian core monsoon zone (CMZ). Here we present the first high resolution, well-dated, multiproxy reconstruction of Holocene palaeoclimate from a 10 m long sediment core raised from the Lonar Lake in central India. We show that while the early Holocene onset of-intensified monsoon in the CMZ is similar to that reported from other ISM records, the Lonar data shows two prolonged droughts (PD, multidecadal to centennial periods of weaker monsoon) between 4.6-3.9 and 2-0.6 cal ka. A comparison of our record with available data from other ISM influenced sites shows that the impact of these PD was observed in varying degrees throughout the ISM realm and coincides with intervals of higher solar irradiance. We demonstrate that (i) the regional warming in the Indo-Pacific Warm Pool (IPWP) plays an important role in causing ISM PD through changes in meridional overturning circulation and position of the anomalous Walker cell; (ii) the long term influence of conditions like El Nino-Southern Oscillation (ENSO) on the ISM began only ca. 2 cal ka BP and is coincident with the warming of the southern IPWP; (iii) the first settlements in central India coincided with the onset of the first PD and agricultural populations flourished between the two PD, highlighting the significance of natural climate variability and PD as major environmental factors affecting human settlements. (C) 2014 Elsevier B.V. All rights reserved.