Resolving contradictory hypotheses concerning prolonged late Miocene El Niño-like conditions using the first high-resolution equatorial Pacific climate records

使用第一份高分辨率赤道太平洋气候记录解决有关长期晚中新世厄尔尼诺现象的矛盾假设

• 批准号: 408101468
• 负责人: Dr. Thomas Westerhold
• 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: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/408101468?language=en
• 关键词: Resolving; contradictory; hypotheses; concerning; prolonged

A key dispute concerning Neogene climate centres on whether or not permanent El Niño-like conditions existed in the equatorial Pacific during the Late Miocene. Because anthropogenic global warming projections predict an up to 4°C mean temperature increase by 2100, it is of utmost importance to understand the late Miocene climate system, which was on average 4.5 °C warmer than today. Investigating the existence of permanent El Niño-like conditions during the warm late Miocene can provide critical information for the development of future climate. A modern El Niño, when warm sea surface waters extend far across the equatorial Pacific, causes global precipitation and temperature anomalies, due to the important role of the equatorial Pacific Ocean in driving global atmospheric circulation, precipitation, heat transport and carbon cycling. Prolonged El Niño-like conditions may have had serious, widespread, global consequences and potentially triggered the increase in global aridity observed during the late Miocene.The main scientific goal of this proposed project is to test the hypothesis that permanent late Miocene El Nino-like conditions existed in the equatorial Pacific between 6.5 and 9.7 Ma. To resolve this, I propose reconstructing changes in the water column structure and thermocline depth of the Western Pacific Warm Pool (WPWP), at unprecedented glacial-interglacial resolution, by generating high-resolution benthic and planktonic (mixed layer and thermocline) stable isotope records between 6.0-9.7 Ma, using recently recovered sediments from Site U1488 (IODP Expedition 363). Comparing the new WPWP records at glacial-interglacial resolution with eastern equatorial Pacific records will allow short- and long-term changes to be distinguished from each other. We can thereby test the true extent of late Miocene El Niño-like conditions to be tested and characterise the nature of the ~6.5 Ma transition to La Niña-like conditions. The high-resolution benthic stratigraphy will be used to develop an astronomical age model and to provide a robust correlation between the new U1488 records and existing astronomically tuned records from eastern equatorial Pacific Sites U1337 and U1338 (IODP Exp. 320/321). This project may ultimately resolve the late Miocene permanent El Niño debate and significantly advance our understanding of the global consequences of dominant El Niño conditions during climates warmer than the present.

赤道太平洋地区存在着有关新金元气候中心或不永久性的厄尔尼诺风格条件的关键争议，因为人为的全球变暖项目的平均温度高达2100，这一点非常重要，很重要中新世的气候系统平均为4.5°C。在温暖的中新世晚期，在温暖的中新世期间研究了永久性的El Niandit离子，可以为未来气候的发展提供关键的信息。太平洋引起了赤道海洋的全球降水和温度异常，以驱动全球大气循环，热运输和碳循环。在6.5和9.7 Ma之间的赤道中，我提出了在未经预测的冰川冰期分辨率下的水柱结构型的重建变化，通过产生高分辨率）稳定的同位素记录在6.0-9.7 mA之间，使用网站U1488的近期恢复的沉积物（IODP Expedition 363）。要彼此区分，我们可以将真实的中新世类似的内容进行测试，并表征〜6.5 ma的过渡到LaNiña的含量地层将建立一个天文年龄模型，并提供新的U1488记录与来自东部赤道太平洋网站U1337和U1338（IODPExp。320/321）之间的现有天文记录之间的牢固相关性。永久性的厄尔尼诺辩论，并显着促进了我们对气候在温暖的气候中占主导地位的全球后果的理解。