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Process study of vertical mixing near the sea floor inside the central valley of the Mid-Atlantic Ridge near 37°N

北纬37°附近大西洋中脊中央山谷内海底附近垂直混合过程研究

基本信息

批准号：
189959130
负责人：
Professor Dr. Torsten Kanzow, Ph.D.
金额：
--
依托单位：
GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2010
资助国家：
德国
起止时间：
2009-12-31 至 2017-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/189959130?language=en
关键词：
Process study vertical mixing near

项目摘要

Vertical mixing associated with dissipation of turbulent kinetic energy sustains the circulation of the deep and abyssal ocean. New evidence is emerging that the highest mixing rates are found within the central valleys and ridge flank (transform) canyons of mid-oceanic ridge systems. An expedition is proposed to take place in August 2010 during which near-bottom oceanographic and marine-geologic measurements will be carried out in the central valley of the Mid-Atlantic Ridge near 37°N, using an autonomous underwater vehicle (AUV), complemented by “classical” lowered and mooring-based techniques. It is currently unclear, which physical mechanisms control the intense turbulent dissipation in deep ocean canyons. Recent studies point to a potential role of hydraulic jumps, which have been observed in shallow water studies. We aim at testing whether tidally varying hydraulic jumps can explain the observed large vertical mixing over a sill in the central valley. To resolve the jumps AUV-based high-resolution horizontal fields of near-bottom turbulent kinetic energy dissipation and of flow velocities will be obtained. Further, high-resolution AUV multi-beam echosounder mapping will allow us to study (i) the relationship between vertical mixing processes and the bathymetry, and (ii) the dynamic processes underlying the “mixing active” morphology.

与湍动能耗散有关的垂直混合维持了深海和深海的循环。新的证据表明，最高的混合率出现在大洋中脊系统的中央峡谷和脊侧(变换)峡谷中。拟于2010年8月进行一次考察，在此期间，将使用自主水下航行器，辅之以“经典”的下沉和系泊技术，在北纬37°附近的大西洋中脊中央谷地进行近海底海洋学和海洋地质测量。目前还不清楚是什么物理机制控制了深海峡谷中强烈的湍流消散。最近的研究指出了水力跳跃的潜在作用，这在浅水研究中已经观察到了。我们的目的是测试潮汐变化的水力跳跃是否可以解释在中央山谷的基床上观察到的大型垂直混合。为了解决跳跃问题，将获得基于AUV的高分辨率水平近底湍动能耗散场和流速场。此外，高分辨率AUV多波束回声测绘将使我们能够研究(1)垂直混合过程与水深测量之间的关系，以及(2)“混合活跃”形态背后的动力学过程。