Upwelling in the Atlantic sector of the Southern Ocean

南大洋大西洋部分的上升流

• 批准号: 197638789
• 负责人: Professorin Dr. Monika Rhein
• 金额: --
• 依托单位: Abteilung Ozeanographie
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2011
• 资助国家: 德国
• 起止时间: 2010-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/197638789?language=en
• 关键词: Upwelling; Atlantic; sector; Southern; Ocean

Upwelling is an important process in setting the characteristic of the mixed layer. Upwelling also provides a pathway for gases, nutrients, and other compounds from the ocean’s interior into the mixed layer and ultimately into the atmosphere. Since the upwelling velocities are small, they cannot be measured directly. Recently, Rhein et al. (2010) exploited the helium isotope disequilibria found in the equatorial eastern Atlantic to infer upwelling speeds, upwelling rates, and vertical heat fluxes between the mixed layer and the ocean’s interior. The disequilibrium in the mixed layer is caused by upwelling of 3He-enriched water from the interior. The surplus 3He is introduced into the deep ocean by hydrothermal activities.A first survey of historical Helium isotope data in the Antarctic Circumpolar Current (ACC) and the Weddell Sea showed, that the mixed layer is also enriched with 3He, which in summer months is supplied by upwelling of water from below the mixed layer. Although the first estimates of upwelling velocities from the historical data set look promising, the present Helium data lack a sufficient resolution in the upper 200-300m to determine the horizontal and vertical He gradients, necessary for the compilation of the upwelling velocity and of the contribution of diapycnal mixing. Here we propose to take the historical He data, and a new dedicated He data sets to be taken in November 2010 – February 2011 during the POLARSTERN cruise ANT 27/2 and January- February 2012 during POLARSTERN cruise ANT28/3 to calculate upwelling speeds and –rates in the Weddell Sea and the ACC, as well as heat fluxes between the interior and the mixed layer.This proposal is part of the Cluster “ Eddies and Upwelling: Major Factors in the Carbon Budget ofthe Southern Ocean”

上升流是确定混合层特征的重要过程。上升流还为气体、营养物和其他化合物从海洋内部进入混合层并最终进入大气层提供了途径。由于上升流速度很小，因此它们不能进入。最近，Rhein 等人（2010）利用赤道东大西洋发现的氦同位素不平衡来推断上升流速度、上升流率，混合层与海洋内部之间的垂直热通量的不平衡是由于富含 3He 的水从内部上升而引起的。剩余的 3He 通过热液活动被引入深海。南极绕极流 (ACC) 和威德尔海的氦同位素数据表明，混合层也富含 3He，在夏季由 3He 提供尽管根据历史数据集对上升流速度的初步估计看起来很有希望，但目前的氦气数据在上层 200-300 m 内缺乏足够的分辨率来确定水平和垂直的氦气梯度，而这对于确定氦气梯度是必需的。在此，我们建议采用历史 He 数据，并在 2010 年 11 月至 2 月期间采用新的专用 He 数据集。 2011 年 POLARSTERN 巡航 ANT 27/2 期间和 2012 年 1 月至 2 月 POLARSTERN 巡航 ANT28/3 期间，计算威德尔海和 ACC 的上升流速度和速率，以及内部和混合层之间的热通量。本提案是“涡流和上升流：南大洋碳预算的主要因素”集群的一部分