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）是大气热量和水分的主要来源，是一个深大气对流和强降雨的区域。WPWP海面温度的微小扰动影响Hadley和Walker环流上升支对流的位置和强度，扰动行星尺度大气环流、大气加热和热带水文，以及温跃层中的热量和二氧化碳储存及其通过印度尼西亚通流向印度洋的输送。与现代气候学的背离将如何影响该地区的水文气候条件，也就是说，是否应该预期更严重的干旱或更强的季风降雨。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，摧毁人口稠密地区的当地经济。国际海洋探索计划（IODP）第363次远征队旨在记录整个西海近第三纪（~0-20 m）气候和古海洋变率在千年和轨道时间尺度上对辐射强迫变化和背景气候状态变化的响应及其驱动机制，以改进该地区气候变化的预测。该奖项支持对363远征队收集的两个岩心的研究。在巴布亚新几内亚（PNG）北部约200 km的Manus盆地U1486站点生成了轨道尺度的底栖生物同位素记录，时间跨度为晚上新世（约2.25 Ma）至今。氧同位素地层学将是解释该站点水文气候变异代用重建的关键，包括对来自PNG的陆源河流输入和浮游有孔虫同位素和元素记录的XRF分析。底栖有孔虫碳同位素和痕量金属记录将用于评估更新世中晚期中水温和碳含量的变化如何影响WPWP的水文特征及其对区域和全球气候的影响。第二个地点（U1485）位于巴布亚新几内亚北部边缘，靠近Sepik/Ramu河口，其特点是沉积速率非常高，将用于重建过去500年以前的间冰期的气候条件。具体来说，将生成终端I和全新世的浮游生物和底栖生物同位素和元素记录，并与终端II和IV以及随后比现在更温暖的间冰期峰值（即Eemian/ MIS 5e和MIS 11）进行比较，以评估WPWP上层海洋如何响应与下个世纪类似的预测边界条件的偏差。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，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.