...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Earth and Planetary Science Letters: A Letter Journal Devoted to the Development in Time of the Earth and Planetary System >Millennial-scale Agulhas Current variability and its implications for salt-leakage through the Indian-Atlantic Ocean Gateway
【24h】

Millennial-scale Agulhas Current variability and its implications for salt-leakage through the Indian-Atlantic Ocean Gateway

机译：千禧年规模Agulhas当前的变化及其对印度-大西洋通道漏盐的影响

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The inter-ocean exchange of warm and salt-enriched waters around South Africa (Agulhas leakage), may have played an important role in the mechanism of deglaciations. Paleoceanographic reconstructions from the Agulhas leakage corridor show that leakage maxima occurred during glacial terminations. Therefore enhanced leakage has been suggested as a forcing mechanism to shift the Atlantic Meridional Overturning Circulation into the interglacial mode of circulation. At present, studies have not considered that upstream changes in the properties of the Agulhas Current itself may, in part, explain the observed variability in the Agulhas leakage and play an important role in defining the upper ocean hydrography of the South Atlantic. Here, we present a multi-proxy record from a marine sediment core (CD154 17-17K) located in the main trajectory of the Agulhas Current that spans the past 100 kyr. The record shows considerable variability in reconstructed upper ocean temperatures and salinity. We also find that the relative abundance of tropical and sub-tropical planktic foraminifera, previously used as a proxy for Agulhas leakage fauna, shows considerable upstream variability, likely reflecting changes in the hydrography of the southwest Indian Ocean sub-gyre (SWIOSG) and upper ocean temperatures. Idealised numerical model simulations demonstrate that both a shifting and an intensification of the Southern Hemisphere westerlies modify the vigour of the SWIOSG. These changes also drive increased kinetic and eddy variability in the Agulhas Return Current that potentially enhances cross frontal mixing of southern sourced waters into the SWIOSG system. Our results suggest that variability in the upstream Agulhas Current hydrography is strongly linked to the dynamics of the Agulhas Return Current and strength of the SWIOSG and that downstream variability in the leakage area (Atlantic sector) at least partly reflects regional variations of the Agulhas Current as a whole.
机译：南非周围温暖和富含盐分的水域之间的大洋交换（Agulhas渗漏）可能在冰川融化机制中发挥了重要作用。 Agulhas渗漏走廊的古海洋学重建表明，在冰川终止期间发生了渗漏最大值。因此，已经提出增强的泄漏作为将大西洋子午线翻转环流转变为冰间环流模式的强迫机制。目前，研究还没有考虑到Agulhas Current自身性质的上游变化可能部分解释了Agulhas渗漏的观测变异性，并且在确定南大西洋的上层海洋水文学中起着重要作用。在这里，我们提供了来自Agulhas Current主轨迹跨越过去100年的海洋沉积物芯（CD154 17-17K）的多代理记录。记录显示，重建的上层海洋温度和盐度变化很大。我们还发现，以前用作Agulhas渗漏动物的代理的热带和亚热带板状有孔虫的相对丰度显示出相当大的上游变化，这可能反映了西南印度洋次回转（SWIOSG）和上层的水文学变化。海洋温度。理想的数值模型仿真表明，南半球西风的移动和加剧都改变了SWIOSG的活力。这些变化也推动了Agulhas回水流的动力学和涡流变化性增加，从而有可能增强南部水域水到SWIOSG系统的跨额混流。我们的结果表明上游Agulhas Current水文的变化与Agulhas回水流的动力学和SWIOSG的强度密切相关，泄漏区域（大西洋地区）的下游变化至少部分反映了Agulhas Current的区域变化。整个。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号