Transforming our understanding of the Indonesian Throughflow variability and its climatological influence, long coral records from strategic sites

改变我们对印度尼西亚流量变化及其气候影响、战略地点的长期珊瑚记录的理解

• 批准号: NE/W001314/1
• 负责人: Jens Zinke
• 金额: $ 65.77万
• 依托单位: University of Leicester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FW001314%2F1
• 关键词: Transforming; our; understanding; Indonesian; Throughflow

The Indonesian Throughflow (ITF) current is the world's only major oceanic current situated in the tropics. It propagates heat and salt-content anomalies from the Earth's largest heat engine, the vast mass of warm and relatively low-salinity ocean surface waters of the Western Pacific Warm Pool, into the Indian Ocean and beyond. ITF variability is, therefore, deeply implicated in modulating sea-level-, climate- and weather-anomalies seasonally over southeast Asia, Australia and Africa, affecting biodiverse ecosystems and the lives of millions of people. However, our understanding of ITF variability is limited to instrumented observational records that date back to only 1984, and these records are often discontinuous. These data sets provide a basic understanding of the linkages between very recent ITF variability and extreme climate events such as the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). However, because the record is so short, these analyses struggle to isolate the anthropogenically-forced component of change from natural variability. This problem severely limits our ability to make confident predictions of the response of the ITF and the Asian, Australian and African monsoons to 21st century human-induced warming. Longer records of ITF-variability are desperately needed.This project will transform our understanding of ITF variability. It will reach back into the past to pre-industrial times by extending the records of ITF temperature and salinity from 1984 to 1770. Our analysis will be based on the chemistry of giant coral (Porites sp.) skeletons. These corals live in a "bulls-eye" location for ITF outlet waters, on the Northwest Australian margin where ITF-temperature and ITF-salinity anomalies are greatest and ITF-control is unequivocal (CfS, Fig. 1). The coral cores were already collected in 2011 and precisely dated by annual growth band counting (by Project Partners Lough and Cantin). Our pilot study data from the youngest layers of the coral skeletons from our study site demonstrate that these corals faithfully record ITF-temperature and -salinity anomalies (CfS, Fig. 2). Our new 240 year-long record of ITF temperature and salinity will be combined with numerical ocean model outputs (involvement of Project Partners England and Feng) and published monsoon records (e.g., tree-ring data sets from Australia, South East Asia and Africa) to revolutionise understanding of ITF-variability and its climatological influence.Our project will make a step-change contribution to our knowledge of the relationship between south-eastern Indian Ocean and onshore-offshore Austral-Asian climate, including rainfall, floods, drought and bushfires. This is vital for preparing societies for a warming climate and an ever-increasing human footprint in the Austral-Asian-African monsoon regions.

印度尼西亚穿流（ITF）流是世界上唯一位于热带的主要洋流，它从地球上最大的热力发动机（西部大量温暖且盐度相对较低的海洋表面水域）传播热量和盐含量异常。因此，太平洋暖池、印度洋及其他地区的 ITF 变化与东南亚、澳大利亚和非洲的海平面、气候和天气异常季​​节性调节密切相关。然而，我们对 ITF 变异性的理解仅限于 1984 年的仪器观测记录，并且这些记录通常是不连续的。 ITF 变化和极端气候事件，如厄尔尼诺南方涛动 (ENSO) 和印度洋偶极子 (IOD) 然而，由于记录很短，这些分析很难分离出这些事件。这一人为强制的自然变化因素严重限制了我们对 ITF 以及亚洲、澳大利亚和非洲季风对 21 世纪人类引起的变暖的反应做出可靠预测的能力。该项目将通过将 ITF 温度和盐度的记录从 1984 年延伸到 1770 年，从而改变我们对 ITF 变化的理解。我们的分析将基于巨型珊瑚 (Porites sp.) 骨骼的化学成分，这些珊瑚生活在 ITF 出口水域的“靶心”位置，位于澳大利亚西北部边缘，那里的 ITF 温度和 ITF 盐度异常最为严重。 ITF 控制是明确的（CfS，图 1），珊瑚核心已于 2011 年收集，并通过年度生长带计数精确确定了日期（由项目合作伙伴 Lough 和 Cantin 进行）。来自我们研究地点最年轻的珊瑚骨骼层的试点研究数据表明，这些珊瑚忠实地记录了 ITF 温度和盐度异常（CfS，图 2）。结合数值海洋模型输出（项目合作伙伴 England 和 Feng 的参与）和已发布的季风记录（例如来自澳大利亚、东南亚和非洲的树木年轮数据集），以彻底改变了解 ITF 变异性及其气候影响。我们的项目将为我们了解东南印度洋与澳大利亚-亚洲陆上和近海气候之间的关系（包括降雨、洪水、干旱和丛林大火）做出重大贡献。对于让社会做好应对气候变暖和澳大利亚-亚洲-非洲季风地区不断增加的人类足迹的准备至关重要。