Persistent multidecadal power of the Indian Summer Monsoon
Persistent multidecadal power of the Indian Summer Monsoon
复制标题
DOI：
10.1016/j.epsl.2009.12.017
复制
发表时间：
2010-02-15
影响因子：
5.3
通讯作者：
Cannariato, Kevin
中科院分区：
文献类型：
--
作者：
Berkelhammer, Max;Sinha, Ashish;Cannariato, Kevin
印度夏季风（ISM）降水的仪器记录显示两个完整的表现推断的几十年循环。目前，没有降水敏感的代理记录从印度次大陆有必要的分辨率和长度，以充分评估这一观察到的功能是否是一个内在的方面，ISM系统在较长的时间尺度。在这里，我们提出了令人信服的证据，持久性的这个周期使用千年的长度（公元600-1550年）和分年度解决洞穴氧同位素记录（三角洲O-18）在印度中东部的Dandak洞穴。该记录显示了高度的相关性与一个洞穴为基础的亚洲季风重建从万象洞在中国中北部的年度到十年的时间尺度上显示这些发现的区域意义。在我们的季风重建所观察到的时期与Gleissberg太阳活动周期和北大西洋（AMO）的几十年海表温度变化，这两者都经常被引用为突出的起搏器ISM变化的几十年的时间尺度上的相似。我们记录ISM降水量和太阳变率之间的瞬态一致性，持续专门在世纪之前和中世纪气候异常（名义上，公元950-1300年）。这里提出的SFV-季风关系的非平稳性质可能是热带海洋-大气动力学对太阳-季风联系的时变影响的证据;然而，不可能有意义地表明，这一时期的相干性只不过是具有相似光谱的两个时间序列的人工制品。因此，我们倾向于将我们的记录解释为太阳变率在驱动ISM持续数十年变率中的最小作用的证据。北大西洋的多年代SST变率仍然是这一周期持续存在的可能替代驱动因素。无论成因机制（S），振幅和区域签名的观测周期在ISM降水突出其社会的重要性，相对于预测ISM降水的几十年的时间尺度。(C)2009爱思唯尔有限公司版权所有。
The instrumental record of Indian Summer Monsoon (ISM) precipitation displays two complete manifestations of an inferred multidecadal cycle. Hitherto, no precipitation-sensitive proxy record from the Indian subcontinent has had the necessary resolution and length to adequately assess whether this observed feature is an inherent aspect of the ISM system on longer timescales. Here we present compelling evidence for persistence of this cycle using a millennial length (AD 600-1550) and sub-annually resolved speleothem oxygen isotope record (delta O-18) from Dandak Cave in east-central India. The record displays a high degree of correlation with a speleothem-based Asian monsoon reconstruction from Wanxiang Cave in north-central China on annual to decadal timescales showing the regional significance of these findings. The observed period in our monsoon reconstruction is similar to that associated with the Gleissberg solar cycle and multidecadal sea surface temperature variability in the north Atlantic (AMO), both of which are often cited as the prominent pacemakers of ISM variability on multidecadal timescales. We document transient coherence between ISM precipitation amount and solar variability that persists exclusively in the century prior to and during the Medieval Climate Anomaly (nominally, AD 950-1300). The non-stationary nature of the SFV-monsoon relationship presented here may be evidence of the time-varying influence of tropical ocean-atmosphere dynamics on the solar-monsoon link; however, it is not possible to show with significance that this period of coherence is anything more than an artifact of two timeseries with similar spectra. We therefore, are inclined to interpret our record as evidence of a minimal role of solar variability in driving persistent multidecadal variability of the ISM. Multidecadal SST variability in the North Atlantic remains as the likely alternative driver for persistence of this cycle. Regardless of the causative mechanism(s), the amplitude and regional signature of the observed cycle in ISM precipitation highlight its societal importance with respect to forecasting ISM precipitation on multidecadal timescales. (C) 2009 Elsevier B.V. All rights reserved.