North Atlantic Bottom Water Temperature and Ice Volume Records from the Mid-Pleistocene Transition

中更新世过渡期北大西洋底层水温和冰量记录

• 批准号: 1436014
• 负责人: Heather Ford
• 金额: $ 22.13万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-10-01 至 2016-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1436014&HistoricalAwards=false
• 关键词: North; Atlantic; Bottom; Water; Temperature

Understanding the effects of solar strength, global ice volume and carbon dioxide levels on the global climate system is essential for climate models' ability to reconstruct past and future climate. In particular, studying past ice volume variations are of vital importance to predicting ice sheet stability and sea level change. During the mid-Pleistocene transition (~600,000 to 1,200,000 years ago), the climate's response to solar strength changed dramatically and variations in ice volume and carbon dioxide levels may have contributed to this transition. This project aims to resolve changes in ocean bottom water temperature and circulation to evaluate global ice volume variability as a potential driving factor for the mid-Pleistocene transition. The broader impacts include support for a female postdoctoral scientist, undergraduate research experiences, and educational displays designed for the Lamont-Doherty Earth Observatory Core Repository in New York.Most climate interpretations for the mid-Pleistocene transition come from oxygen isotope records from benthic foraminifera, which record a combination of temperature and ice volume signals. The Mg/Ca ratio of benthic foraminifera may serve as an independent proxy of ocean bottom water temperature and has been used to separate ocean bottom water temperature and ice volume components in the oxygen isotope records from benthic foraminifera. Currently there are only two high-resolution records of ocean bottom water temperature and seawater oxygen isotope composition (as a proxy for ice volume) during the mid-Pleistocene transition. However, these studies record fundamentally different trends, suggesting different mechanisms for the mid-Pleistocene transition. This project will use coupled Mg/Ca and oxygen-isotope values of benthic foraminifera to evaluate regional and global signals in ocean bottom water temperature and ice volume signals from the North Atlantic. These data will be used to assess any changes in ocean bottom water temperature, the timing of ice volume growth and the magnitude of sea level variation during the mid-Pleistocene transition. This will aid climate modelers in setting boundary conditions for the mid-Pleistocene transition and in identifying the key factors influencing global climate.

了解太阳能，全球冰量和二氧化碳水平对全球气候系统的影响对于气候模型重建过去和未来气候的能力至关重要。特别是，研究过去的冰量变化对于预测冰盖稳定性和海平面变化至关重要。在中世过渡期间（〜600,000至1,200,000年前），气候对太阳强度的反应发生了巨大变化，冰量和二氧化碳水平的变化可能导致了这种过渡。该项目旨在解决海洋底部水温和循环的变化，以评估全球冰量变异性，这是中世代中期过渡的潜在驱动因子。更广泛的影响包括对女性博士后科学家的支持，本科研究经验以及为纽约Lamont-Doherty Earth天文台核心库库设计的教育展示。中期过渡的最多气候解释来自氧气同位素记录，来自Benthic Foraminifera的氧气同位素记录。记录温度和冰量信号的组合。底栖有孔虫的mg/ca比可作为海洋底部水温的独立代理，并已用于将氧同位素记录中的海洋底部水温和冰分成分与底栖有孔虫分离。目前，在中期过渡期间，海洋底部水温和海水氧同位素组成（作为冰量的代理）只有两个高分辨率记录。然而，这些研究从根本上记录了不同的趋势，这表明了中期过渡的不同机制。该项目将使用底栖有孔虫的MG/CA和氧同位素值耦合，以评估来自北大西洋的海洋底部水温和冰量信号中的区域和全球信号。这些数据将用于评估海洋底部水温的任何变化，冰量生长的时机以及中期过渡期间海平面变化的幅度。这将有助于气候建模者为中期过渡设置边界条件，并确定影响全球气候的关键因素。