Collaborative Research: Quantifying the ocean's response to solar forcing:Multidecadal to century-scale variability of North Atlantic SSTs over recent millennia

合作研究：量化海洋对太阳强迫的响应：近千年来北大西洋海温数十年至百年尺度的变化

• 批准号: 1103519
• 负责人: Peter DeMenocal
• 金额: $ 26.61万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-15 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1103519&HistoricalAwards=false
• 关键词: Collaborative; Research; Quantifying; ocean; response

The purpose of this project is to develop the first detailed, calendrically-dated records of North Atlantic Sea Surface Temperature (SST) variability in order to investigate the ocean's response to natural solar forcing at multi-decadal to century time scales over the last 3000 years. Despite the availability of reliable SST proxies and of sampling sites with the necessary high deposition rates, there exist no reconstructions of the North Atlantic basin-scale SST field over past millennia based directly or substantially on ocean observations. This is due almost entirely to the lack of adequate age-dating control in marine sediments. This collaborative project, undertaken by a team from both Columbia University's Lamont-Doherty Earth Observatory and the University of Colorado, Boulder, develops a new marine application of the so-called radiocarbon "wiggle-match" dating method in which reliable calendar age estimates are obtained free of assumptions regarding the size and past variability of the local marine reservoir age, which is the principle source of dating uncertainty. Because the method objectively maps down-core marine sediment radiocarbon variations to the late Holocene radiocarbon calibration in tree-rings, which also contains a record of initial atmospheric radiocarbon activity controlled (at the timescale of interest here) largely by variations in the Sun's open magnetic flux, it provides for direct comparison of SST and solar proxy variability in the same sediments. The researchers makes use of eight high-accumulation rate sediment cores with a basin-wide distribution selected to capture the spatial expression of the leading modes of Atlantic temperature variability today (the NAO and AMO). Chronologies for each core are based on AMS radiocarbon dating (at a nominal resolution of 40 years) with calendar ages assigned objectively using an automated wiggle-match algorithm developed for this project. SST reconstructions will be based on foraminiferal oxygen isotope stratigraphy and Mg/Ca, which provide a reliable estimate of past calcification temperature. Together these data will provide the observations necessary to test for any possible basin-wide SST pattern response to solar forcing and whether this response has features in common with the North Atlantic Oscillation (NAO), Atlantic Multidecadal Oscillation (AMO) or with other previously simulated responses. Broader Impacts: This work directly addresses the need to characterize natural climate variability as needed in order to separate ongoing responses to natural and anthropogenic forcing agents and to improve predictive models. Such characterization is presently lacking over the oceans although ocean regions are spatially and, in many instances, energetically dominant. The project will also support education and research training for a PhD student at Columbia University.

该项目的目的是开发北大西洋海面温度（SST）变异性的第一个详细的日历日期记录，以调查过去3000年来海洋对自然太阳能强迫的反应。尽管可靠的SST代理和具有必要高沉积速率的采样地点，但在过去的几千年中，北大西洋盆地规模的SST领域没有重建，直接基于海洋观察。这几乎完全是由于海洋沉积物中缺乏足够的年龄控制。 这个由哥伦比亚大学的Lamont-Doherty地球天文台和科罗拉多大学Boulder的团队进行的合作项目开发了对所谓的放射性碳“ Wiggle-Match”日期的新应用，其中可靠的日历年龄估计是可以在iSpriper of Princir of Princir of Princir of Princir of Princir of Princiriir oveririir of nive of decriper of nipiriir of nive insiriir of nive insiriir of nive insiriir of nistive of nistive of nive unsirii for nive noviriir的估计。 Because the method objectively maps down-core marine sediment radiocarbon variations to the late Holocene radiocarbon calibration in tree-rings, which also contains a record of initial atmospheric radiocarbon activity controlled (at the timescale of interest here) largely by variations in the Sun's open magnetic flux, it provides for direct comparison of SST and solar proxy variability in the same sediments. 研究人员利用八个高积累速率的沉积物核心，并选择了盆地范围的分布，以捕获当今大西洋温度变化的主要模式的空间表达（NAO和AMO）。每个核心的时间顺序是基于AMS放射性碳年代（以40年的标称分辨率），其日历年龄使用为该项目开发的自动Wiggle匹配算法客观地分配。 SST重建将基于有孔虫的氧同位素地层和mg/ca，可靠地估算了过去的钙化温度。这些数据将共同提供必要的观察结果，以测试对太阳强迫的任何可能的盆地范围内的SST模式响应，以及此响应是否具有与北大西洋振荡（NAO），大西洋多年代振荡（AMO）或其他先前模拟的响应相同的特征。 更广泛的影响：这项工作直接解决了根据需要表征自然气候变化的必要性，以分离对自然和人为强迫剂的持续反应并改善预测模型。尽管海洋地区在空间上是空间上的，并且在许多情况下，这种特征目前缺乏海洋。该项目还将支持哥伦比亚大学一名博士生的教育和研究培训。