Testing the Hypothesis: Recurring Century-Length Episodes of Reduced Summer Monsoon Precipitation Are Linked to Ocean/Atmosphere Dynamics in the Tropical Pacific

该奖项扩展了热带太平洋-大气变率和季风变率的代理数据库，以便研究在更长的时间尺度上，热带海洋与印度和中国的季风之间是否存在持续的耦合。该研究是该小组两年前开始的一个项目的延续，该项目通过分析在印度和中国收集的年代洞穴中的氧同位素来重建季风区的高分辨率（年代际分辨率）降水历史，并将其与印度尼西亚的高分辨率（多年代际分辨率）海面温度和降水变化的代理记录进行比较。该研究的核心气候论点是，热带太平洋和印度洋存在百年和千年的海洋-大气变率模式，它涉及温暖水域的轨迹和印度尼西亚上空大气对流强度的变化以及印度洋海面温度梯度，这种变率与落在印度和中国核心季风区的夏季降水强度的变化有关。研究人员正在研究以下问题：热带西部太平洋和印度洋是否存在与印度和中国季风区降水变化有关的百年尺度气候（SST）变化的持续模式？-印度和亚洲季风降雨是否有持续的干旱复发模式？-印度和中国的重大文化活动是否与持续干旱或异常干旱有关？研究人员将通过扩大热带西部太平洋和印度洋海面温度变化的重建，开发印度和亚洲季风变化的复合洞穴氧同位素记录，以及进行全新世千年尺度气候记录的时间序列分析和相互比较来解决这些问题。从这项研究中获得的数据将有助于了解对人口稠密地区有重大影响的大尺度大气特征（亚洲季风）的气候学。该项目具有强大的国际合作教育和研究组成部分，包括支持研究和博士后学者，以及中国、印度和台湾的科学家和学生的积极参与。

This award extends the proxy data base of tropical Pacific ocean-atmospheric variability and monsoon variability in order to investigate whether, on longer time scales, there has been a persistent coupling between the tropical Ocean and monsoons of India and China. The research is a continuation of a project begun two years ago by this group to reconstruct high resolution (decadal resolution) precipitation histories for the monsoon regions through analyses of oxygen isotopes in dated speleothems collected in India and China and compare these to high resolution (multi-decadal resolution) proxy records of sea surface temperature and precipitation variability in Indonesia. The climate thesis at the core of the research is that a centennial and a millennial-length pattern of ocean-atmospheric variability exists within the tropical Pacific and Indian Oceans that involves shifts the locus of warm waters and the strength of atmospheric convection over Indonesia and sea surface temperature gradients in the Indian Ocean and this variability is associated with varying strength of summer precipitation falling on the core monsoon regions of India and China. The researchers are pursuing the following research questions:- Has there been a persistent pattern of centennial-scale climate (SST) variability in the western tropical Pacific and Indian Ocean that is associated with variable precipitation over the monsoon regions of India and China?- Is there a persistent pattern of drought recurrence in the Indian and Asian monsoon rainfall?- Were major cultural events in India and China associated with sustained or exceptional droughts?The researchers will address these questions by expanding the reconstruction of western tropical Pacific and Indian Ocean sea surface temperature changes, developing composite speleothem oxygen isotope records of Indian and Asian monsoon variability, and conducting time series analysis and inter-comparisons of Holocene millennial-scale climate records.The data gained from this research will aid the understanding of the climatology of a large-scale atmospheric feature (Asian monsoon) that has significant impact on a densely populated region. The project has a strong international collaborative education and research component that includes support for research and postdoctoral scholars and active participation by scientists and students in China, India, and Taiwan.