Pacific circulation during the middle Miocene climate transition: Monitoring ocean overturning and the east-west hydrographic gradient

中新世中期气候转变期间的太平洋环流：监测海洋翻转和东西向水文梯度

• 批准号: 28791703
• 负责人: Professor Dr. Wolfgang Kuhnt
• 金额: --
• 依托单位: College of Earth, Ocean, and Atmospheric Sciences
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2009-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/28791703?language=en
• 关键词: Pacific; circulation; during; middle; Miocene

About 13.9 million years ago, the Earth s climate cooled dramatically after an extended period of relative warmth. This key transition in Earth s climatic and biotic evolution, which marked the final stage of stepwise Cenozoic cooling, remains one of the most enigmatic episodes in Earth s Cenozoic climate history. While there is evidence that orbital forcing and atmospheric CO2 variations strongly influenced climate evolution, the role of the ocean circulation as enhancer or driver of climate change remains unclear. Our primary goals are to investigate circulation changes in the Pacific during the middle Miocene warm climate phase and subsequent global cooling. In particular, we will test the hypothesis that global cooling and ice-sheet expansion at - 13.9 Ma coincided with a fundamental re-organization in Pacific circulation and initiation of a West Pacific Warm Pool system. Our investigation will provide a synthesis of ocean chemistry proxies that will allow detailed correlation of paleoceanographic events in different regions of the Pacific and help constrain modeling studies of past and future climate. Furthermore, the early middle Miocene climate optimum represents an exceptional analogue to study the causes and consequences of global warming, in particular the potential switches in deep-water sources during intervals of rapid warming.

大约1390万年前，地球的气候在经历了一段相对温暖的时期后急剧降温。地球气候和生物演化的这一关键转变标志着新生代逐步变冷的最后阶段，仍然是地球新生代气候史上最神秘的事件之一。虽然有证据表明，轨道强迫和大气CO2变化强烈影响气候演变，但海洋环流作为气候变化的增强者或驱动者的作用仍不清楚。我们的主要目标是调查中中新世温暖气候阶段和随后的全球变冷期间太平洋的环流变化。特别是，我们将测试的假设，全球冷却和冰盖扩张在-13.9马正好与太平洋环流的基本重组和西太平洋暖池系统的启动。我们的调查将提供一个综合的海洋化学代理，将允许在太平洋不同地区的古海洋事件的详细相关性，并帮助约束过去和未来的气候建模研究。此外，早中新世中期气候最佳代表了一个特殊的模拟研究全球变暖的原因和后果，特别是在快速变暖的间隔期间，在深水源的潜在开关。