IODP Expedition 363 Objective Research: Evolution of the Indo-Pacific warm pool and deep Pacific circulation during major global climate transitions since the latest Miocene

因为世界的巨大容量？鉴于海洋吸收、储存和释放热量和碳的能力，研究海洋在全球气候变化和全球碳循环中的作用至关重要。印度太平洋暖池（IPWP）是世界上最大的非常温暖的海洋表面温度（≥28&#730；C）。美国的海洋和大气最大的能量和水分来源；因此，它与大气环流、降雨模式和全球气候密切相关。在海洋表面之下是太平洋深处，它是世界上最大的盆地。拥有巨大的碳和热储存能力的美国海洋。因此，它在碳循环、热传输和全球气候变化中发挥着关键作用。虽然从现代条件的研究可以清楚地看出，IPWP和深太平洋是气候系统的关键组成部分，但关于这些地区如何响应和参与长期全球气候变化，特别是在全球变暖的情况下，还有很多不为人知的地方。为了探索这些主题，该项目将重点放在过去的地质时代，当时全球气候与今天截然不同。该项目将涉及一名博士后学者和至少十名UCSC的本科生，从而为早期职业科学家和寻求STEM领域培训的本科生提供关键的培训和指导。将特别关注参与原创研究和招募多样化研究团队的本科生。该项目将研究上新世早期暖期和更新世向寒冷冰期气候的过渡。这个时间间隔(6 ？在温暖期和主要的长期气候转变期间，为我们对气候行为的理解提供了宝贵的测试。为此，2016年10月6日至12月8日，国际海洋发现计划远征363 （IODP Exp 363）从IPWP地区的9个地点回收了约7公里的沉积物。作为与其他IODP Exp 363船上科学家国际合作努力的一部分，该项目将实现IODP Exp 363的两个主要目标。首先，为了验证IPWP在全球气候发生重大变化时仍保持稳定的原假设，本文将生成几个IPWP站点（U1482/3和U1488）过去6 myrs浮游有孔虫表面和地下Mg/ ca温度的估计。这些站点之间的比较以及与其他温度代理测量的比较对于评估代理偏差、温跃层的作用以及印度-太平洋通流对IPWP演变的影响至关重要。其次，为了验证中新世晚期和上新世暖期北太平洋有深水形成的观点，将生成两个西太平洋遗址（U1488和U1489）的底栖有孔虫同位素记录。与太平洋其他地方公布的底栖生物同位素数据进行比较，并与模型模拟进行比较，将把这些新的测量结果置于全球背景下。这些数据对高分辨率年龄模型的发展也至关重要，为其他研究核心的研究人员提供了关键框架。总体而言，该项目的结果将与其他363远征队科学家以及海洋和气候建模者产生的数据相结合，以便更深入地了解印度-太平洋地区在全球气候过程中的作用。此外，它将确定北太平洋深水是否在过去的温暖时期形成并促进了全球热输送。

Because of the enormous capacity of the world?s oceans to absorb, store, and release heat and carbon, it is critically important to study the role of the oceans in global climate change and in the global carbon cycle. The Indo-Pacific warm pool (IPWP) is the largest mass of very warm surface ocean temperatures (≥28˚C) of the world?s oceans and the biggest source of energy and moisture to the atmosphere; as such, it is intimately linked to atmospheric circulation, rainfall patterns, and global climate. Beneath the surface ocean is the deep Pacific, which is the largest basin of the world?s ocean with enormous capacity to store carbon and heat. Thus, it plays a critical role in the carbon cycle, in heat transport, and in global climate change. Although it is clear from studies of modern conditions that the IPWP and the deep Pacific are crucial components of the climate system, there is a lot that is not understood about how these regions respond to, and participate in, long term global climate change especially in a warming world. To probe these topics, this project is focused on past geological epochs when global climate was dramatically different than today. This project will involve a post-doctoral scholar and at least ten undergraduates at UCSC, thereby providing critical training and mentoring for an early career scientist and for undergraduates seeking training in STEM fields. There will be special attention placed on undergraduates being involved in original research and in recruiting a diverse team of researchers.This project will investigate the early Pliocene warm period and the transition to the cold Ice Age climate of the Pleistocene. This time interval (6 ? 0 million years ago) provides valuable tests of our understanding of the behavior of the climate during warm periods and during major long-term climate transitions. To this end, from Oct. 6 to Dec. 8, 2016, the International Ocean Discovery Program Expedition 363 (IODP Exp 363) recovered ~7 km of sediment from nine sites in the IPWP region. As part of an international collaborative effort with other IODP Exp 363 shipboard scientists, this project will achieve two of the primary objectives of IODP Exp 363. First, to test the null hypothesis that the IPWP was stable even while there were major changes in global climate, planktonic foraminifera surface and subsurface Mg/Ca-temperature estimates covering the last 6 myrs at several IPWP sites (U1482/3 and U1488) will be generated. Comparison between these sites, and comparison to other temperature proxy measurements will be critical for evaluating proxy biases, the role of the thermocline, and the influence of the Indo-Pacific Throughflow, on the evolution of the IPWP. Second, to test the idea that there was North Pacific deep water formation in the latest Miocene and warm Pliocene period, benthic foraminifera isotope records at two West Pacific sites (U1488 and U1489) will be generated. Comparison to published benthic isotope data from elsewhere in the Pacific, and to modeling simulations, will put these new measurements into a global context. These data will also be critical to the development of high-resolution age models, providing a key framework for other researchers working on the cores. Overall, the results of this project will be combined with data being generated by other Expedition 363 scientists, and with ocean and climate modelers, in order to achieve a deeper mechanistic understanding of the role of the Indo-Pacific region in global climate processes. In addition, it will determine if North Pacific deep water formed and contributed to global heat transport during past periods of warmth.