Tracking Past Shifts of the Eastern Pacific ITCZ with Oxygen Isotopes and Magnesium Paleothermometry

利用氧同位素和镁古温度测量追踪东太平洋 ITCZ 过去的变化

• 批准号: 0402478
• 负责人: Peter DeMenocal
• 金额: --
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0402478&HistoricalAwards=false
• 关键词: Tracking; Past; Shifts; Eastern; Pacific

Abstract: Under this award the PIs will reconstruct the latitudinal migrations of the Intertropical Convergence Zone (ITCZ) in the Pacific Ocean. The location and latitudinal range of the ITCZ in this basin is inseparably tied to ENSO dynamics and to the strength of the equatorial upwelling, which affect global climate through various mechanisms such as ENSO teleconnections. Moreover, anomalous tropical rainfall patterns due to ITCZ shifts can impact the ocean's thermohaline circulation through control of surface salinity, and alter moisture and ecosystem balance over land triggering climate feedbacks via land-vegetation and biogeochemical processes (e.g. methane emissions and carbon storage). The proponents propose a study to investigate variability in this system in the orbital frequency band, encompassing the interval 0-250,000 years BP, which includes glacial stages 2, 6 and 8, and interglacial stages 1, 5 and 7. This is sufficiently long to discern glacial-interglacial (G-I) (100 ky) variability in addition to precession and obliquity forcing (19-23 ky, and 41 ky). The work will focus on four deep sea cores in a N-S transect across the equator (7N-2S) and will involve measurements of planktonic foraminiferal oxygen isotope (d18O) and Mg/Ca ratios as proxies of surface ocean hydrology and temperature respectively.

翻译后摘要：根据这个奖项的PI将重建纬度迁移的热带辐合带（ITCZ）在太平洋。ITCZ在该盆地的位置和纬度范围与ENSO动力学和赤道上升流的强度密不可分，这些动力学和赤道上升流通过ENSO遥相关等各种机制影响全球气候。此外，由于ITCZ变化引起的异常热带降雨模式可以通过控制表面盐度影响海洋的温盐环流，并改变陆地上的水分和生态系统平衡，通过陆地植被和生物地球化学过程（例如甲烷排放和碳储存）引发气候反馈。 支持者建议进行一项研究，调查该系统在轨道频率带的变化，涵盖0- 250，000年BP的间隔，其中包括第2、6和8次冰期以及第1、5和7次间冰期。这是足够长的时间来辨别冰川-间冰期（G-I）（100千公里）的变化，除了岁差和地磁强迫（19-23千公里，和41千公里）。这项工作将侧重于横跨赤道南北断面（7 N-2S）的四个深海岩心，并将涉及测量浮游有孔虫氧同位素（d18 O）和Mg/Ca比率，分别作为表层海洋水文和温度的替代指标。