Global and regional perspectives of Pleistocene paleoceanography in the western Pacific warm pool based on new sites from IODP Expedition 363

西太平洋暖池(WPWP)是大气的主要热量和水汽来源，是大气深层对流和强降雨的地区。WPWP海面温度的小扰动影响了Hadley环流和Walker环流上升支中对流的位置和强度，扰乱了行星尺度的大气环流、大气加热和热带水文，以及温跃层中的热量和二氧化碳的储存，以及它们通过印尼横流输送到印度洋。现代气候学的偏离将如何影响这一地区的水文气候条件，即是否应该预期更严重的干旱或更强的季风雨，模型之间存在分歧。无论哪种方式，这些变化都可能扰乱受影响地区许多人的生活，通过农作物歉收、山体滑坡、沿海地区洪水以及人类和野生动物的损失来摧毁人口稠密地区的当地经济。国际海洋发现计划(IODP)第363次探险力求记录WPWP在千年和轨道时间尺度上整个新近纪(~0-20My)气候和古海洋学变异性的区域表达和驱动机制，以应对辐射强迫和变化的背景气候状态的变化，以便改进对该区域气候变化的预测。该奖项支持对探险363期间收集到的两个岩芯的研究。在巴布亚新几内亚(PNG)以北约200公里处的马努斯盆地U1486站将产生轨道尺度的海底同位素记录，时间跨度为上新世晚期(约2.25 Ma)至今。氧同位素地层学将是解释在该地点获得的水文气候变异性的替代重建的关键，包括对来自PNG的陆源河流输入的XRF分析以及浮游有孔虫的同位素和元素记录。将利用海底有孔虫的碳同位素和痕量金属记录来评估中层水温和碳含量的变化如何影响中更新世至晚更新世的WPWP水文地理学及其对区域和全球气候的影响。位于巴新北缘靠近Sepik/Ramu河口的第二个地点(U1485)，以非常高的沉积速率为特点，将用于重建过去500年间冰期的气候条件。具体地说，将为终止期一和全新世生成浮游和海底同位素和元素记录，并与终止期二和终止期四以及随后比现在更暖的间冰峰(即Eemian/MIS5e和MIS11)进行比较，以评估WPWP上层海洋对与下个世纪预测的边界条件类似的偏离边界条件的反应。资金支持博士后科学家和本科生的研究机会该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The Western-Pacific Warm Pool (WPWP) is a major source of heat and moisture to the atmosphere, being a region of deep atmospheric convection and heavy rainfall. Small perturbations in sea surface temperature of the WPWP influence the location and strength of convection in the rising limb of the Hadley and Walker circulations, perturbing planetary scale atmospheric circulation, atmospheric heating, and tropical hydrology, as well as heat and CO2 storage in the thermocline and their transport to the Indian Ocean through the Indonesian Throughflow. Models disagree how departures from modern climatology will affect the hydroclimate conditions in this area i.e., whether more intense droughts or stronger monsoonal rains should be expected. Either way, these changes can disrupt the lives of many people in regions so affected, devastating local economies of heavily populated regions through crop failure, landslides, flooding of coastal regions, and loss of human and wild lives. International Ocean Discovery Program (IODP) Expedition 363 sought to document the regional expression and driving mechanisms of climate and paleoceanographic variability throughout the Neogene (~0-20 My) in the WPWP on millennial and orbital time scales in response to changes in radiative forcing and varying background climate states, in order to improve predictions of climate change in this region. This award supports research on two of the cores collected during Expedition 363. Orbital-scale benthic isotope record will be generated at Site U1486 in the Manus Basin, ~200 km north of Papua New Guinea (PNG) spanning the late Pliocene (~2.25 Ma) to Present. The oxygen isotope stratigraphy will be key for interpreting proxy reconstructions of hydroclimate variability obtained at this site, including XRF analysis of terrigenous riverine inputs originated from PNG and planktonic foraminiferal isotope and elemental records. Benthic foraminifera carbon isotope and trace metal records will be used to assess how changes in intermediate water temperature and carbon content affected the WPWP hydrography through the mid-to-late Pleistocene and their implications to the regional and global climate. A second site (U1485) on the northern margin of PNG close the Sepik/Ramu River mouths, characterized by very high sedimentation rates, will be used to reconstruct climate conditions during previous interglacials of the past 500 My. Specifically, both planktonic and benthic isotope and elemental records will be generated for Termination I and the Holocene, and compared with Terminations II and IV and the following warmer-than-present interglacial peaks (i.e., Eemian/ MIS 5e and MIS 11) to assess how the WPWP upper ocean responded to deviations from boundary conditions similar to those predicted for the next century. Funding supports a postdoctoral scientist and research opportunities for undergraduate studentsThis award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.