Collaborative Research: Testing Mechanisms of Tropical Climate Change and Variability Using New Cores from the Line Islands

合作研究：利用莱恩群岛的新核心测试热带气候变化和变异的机制

• 批准号: 1401649
• 负责人: Pratigya Polissar
• 金额: $ 30.55万
• 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: 2014-07-15 至 2018-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1401649&HistoricalAwards=false
• 关键词: Collaborative; Research; Testing; Mechanisms; Tropical

Coupled ocean-atmosphere interactions in the tropical Pacific are the leading source of modern global interannual climate variability. This variability, expressed as the El Niño-Southern Oscillation (ENSO), extends far beyond the tropical Pacific, affecting climate and human populations globally. Understanding how climate change alters these interactions is therefore critical for human societies to mitigate and adapt to future change. Discovering whether external forcing or internal variability determines ENSO behavior will greatly deepen our theoretical understanding of ENSO and improve our ability to accurately forecast ENSO behavior under altered climates. In addition to these broad scientific and societal benefits, this project will provide research opportunities for graduate and undergraduate students. The project also provides a platform for the development of K-12 teaching modules, which will be designed in collaboration with public school teachers as well as an undergraduate science teacher in training at the University of California, Santa Cruz.This project is developing records of equatorial Pacific Ocean sea-surface temperature variability during the past 250,000 years to test factors that alter tropical climate and the behavior of the El Niño-Southern Oscillation (ENSO). ENSO is the dominant cause of interannual climate variability globally, yet it is not known how its behavior could change with future climate change. Understanding past changes in the behavior of ENSO, when global temperatures were different, will be a significant advance in this regard. ENSO behavior is reconstructed from the variability of sea-surface temperatures determined by the chemistry of fossil foraminifera shells in deep-sea sediments near the Line Islands, in the central Pacific. The Mg/Ca ratio and oxygen isotope composition of each individual planktonic foraminifera shell records a one-month snapshot of sea-surface temperature. Measurement of many individual shells from a single sediment layer documents the variability of sea surface temperatures over the time of deposition. Because ENSO is the primary cause of sea-surface temperature variability near the Line Islands, past changes in temperature variability show how ENSO behavior changed in the past. These data will test the dynamic response of the equatorial Pacific to changes in solar insolation from Earth's orbit, and to glacial-interglacial changes in global temperature and greenhouse gas (pCO2) forcing, improving our understanding of the ENSO phenomenon and how it might change in the future.

热带太平洋的海洋-大气耦合相互作用是现代全球年际气候变化的主要来源，这种变化以厄尔尼诺南方涛动（ENSO）的形式延伸到热带太平洋以外，影响着全球的气候和人口。因此，气候变化如何改变这些相互作用对于人类社会缓解和适应未来变化至关重要，探索外部强迫或内部变异是否决定ENSO行为将大大加深我们对ENSO行为的理论理解，并提高我们准确预测ENSO行为的能力。除了这些广泛的科学和社会效益外，该项目还将为研究生和本科生提供研究机会，该项目还为开发 K-12 教学模块提供了一个平台，该模块将与公众合作设计。该项目正在开发过去 25 万年赤道太平洋海面温度变化的记录，以测试改变热带气候和海洋行为的因素。南方厄尔尼诺现象振荡 (ENSO) 是全球年际气候变化的主要原因，但目前尚不清楚当全球气温不同时，其行为会如何变化。 ENSO 行为是根据海面温度的变化来重建的，海面温度的变化是由太平洋中部莱恩群岛附近的深海沉积物中的化石有孔虫贝壳的化学成分、镁/钙比和氧气决定的。每个单独的浮游有孔虫贝壳的同位素组成记录了一个月的海面温度快照。对单个沉积物层中许多单独贝壳的测量记录了海面温度随沉积时间的变化。莱恩群岛附近的海面温度变化、过去温度变化的变化显示了 ENSO 行为过去如何变化，这些数据将测试赤道太平洋对地球轨道太阳辐射变化的动态响应，以及气候变化对全球温度和温室气体 (pCO2) 强迫的冰期-间冰期变化的影响，提高了我们对 ENSO 现象及其未来可能发生的变化的了解。