Hongjin Chen, Zhaokai Xu, Germain Bayon, Qingchao Fan, Philip A. E. Pogge von Strandmann, Wei Wang, Tianqi Sun, Tiegang Li
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引用次数: 0
Abstract
Despite the crucial role of the Southern Hemisphere (SH) westerlies in modulating modern and past climate evolution, little is known about their behavior and possible forcing mechanisms during the early Cenozoic. We probe changes in the hydroclimate of southwest Australia during 62–51 Ma, based on sedimentary proxy records from the International Ocean Discovery Program Site U1514 in the Mentelle Basin. Our results reveal a transition from a less humid climate to wetter conditions at mid–high latitudes starting from the early Eocene, which suggests poleward migration of the SH westerlies. This long-term trend is punctuated by short-lived events of aridification during the Mid-Paleocene Biotic Event and wetter intervals during the Paleocene-Eocene Thermal Maximum, indicating additional short-term meridional shifting of the westerlies. We propose that the evolution of SH westerlies was driven by the equator-to-pole temperature gradient regulated by global warming and ephemeral growth of the Antarctic ice sheet.
尽管南半球西风在调节现代和过去的气候演变中起着至关重要的作用,但人们对其在新生代早期的行为和可能的作用机制却知之甚少。我们根据门泰勒盆地国际大洋发现计划 U1514 站点的沉积代用记录,探究了澳大利亚西南部 62-51 Ma 期间水文气候的变化。我们的研究结果表明,从始新世早期开始,中高纬度地区的气候从湿度较低向湿润过渡,这表明了SH西风的向极迁移。在这一长期趋势中,古新世中期生物事件和古新世-始新世热极盛期间的干旱化和湿润化事件都是短暂的,这表明西风又发生了短期的经向移动。我们认为,受全球变暖和南极冰盖短暂增长的调节,赤道到极地的温度梯度推动了 SH 西风的演变。
期刊介绍:
Geophysical Research Letters (GRL) publishes high-impact, innovative, and timely research on major scientific advances in all the major geoscience disciplines. Papers are communications-length articles and should have broad and immediate implications in their discipline or across the geosciences. GRLmaintains the fastest turn-around of all high-impact publications in the geosciences and works closely with authors to ensure broad visibility of top papers.