Collaborative Research: Deep Madagascar Basin (DMB) Experiment: A Quest to Find the Abyssal Water Pathways in the Southwest Indian Ocean

合作研究：马达加斯加深盆地 (DMB) 实验：寻找西南印度洋深海水道的探索

基本信息

批准号：
1924388
负责人：
Matthew Mazloff
金额：
$ 49.84万
依托单位：
University of California-San Diego Scripps Inst of Oceanography
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-09-01 至 2024-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1924388&HistoricalAwards=false
关键词：
Collaborative Research Deep Madagascar Basin

项目摘要

The deep oceans play a crucial role in regulating the Earth's climate on long timescales, by exchanging heat and chemical compounds with the atmosphere and moving them globally. Sometimes surface waters are carried into deepest ocean areas where they are sequestered from further exchanges with the atmosphere over long time periods, but where our knowledge of how water moves is incomplete. For instance, twenty years ago in the Madagascar Basin of the southwest Indian Ocean, deep waters were undisturbed by human influence. But newer measurements in 2018 showed significant amounts of human-made chemical compounds there. These inert compounds enter the ocean at the sea surface from the atmosphere, so when and where the surface water sinks, it carries those compounds to the deep sea. The presence of such compounds in the deep Madagascar Basin after only twenty years counters our previous knowledge about the region. A possible explanation is that deep currents as we understood them may have changed course and strength in the last twenty years. To solve this puzzle, this project will measure the deep currents in the region for the first time, using shipboard instruments during a three-week cruise, and with two types of in-water robotic technologies to follow these currents over several years. Combining these novel measurements with computer simulations, this study will identify the pathways that deep waters travel in the Madagascar Basin, and examine what causes such circulation patterns. It will focus on currents starting near Antarctica, where the water sinks, through fissures in massive seafloor mountain ranges and into the Madagascar Basin, and then on how these deep waters spread to fill the basin. The findings from this project will explain why this part of the ocean is changing so fast, advance the knowledge of deep ocean circulation, and help define how heat and chemical compounds are moved around within the ocean. The proposed research will be a US contribution to the 2nd International Indian Ocean Expedition (IIOE-2) and will provide the first direct estimate of the abyssal circulation and temperature variability in the Deep Madagascar Basin on a basin-scale. The project will support two undergraduate students that will be selected to participate in the DMB cruise. The PIs will also host and mentor UCAR's Significant Opportunities in Atmospheric Research and Science and Woods Hole Partnership in Education students for each summer. Scripps Undergraduate Research Fellowship students will also be mentored each summer. Moreover, the cruise will be available to the Indian Ocean community in general for piggy-back projects, and in particular for oceanographers and students from Mauritius, the start and end port for the cruise.The proposed research will investigate the largely unknown Deep Madagascar Basin (DMB) abyssal circulation, how abyssal temperature varies in the interior, and the effects of the tortuous seafloor topography in steering the abyssal flows. The primary objective is to find out by which pathway(s) the younger abyssal water that enters through deep fracture zones in the Southwest Indian Ridge spreads in the basin, which is crucial for a better understanding of the Indian Ocean Meridional Overturning Circulation and its variability. To determine the pathways and the transformation of the abyssal waters in the basin interior, an array of 75 floats ballasted to drift at 4000-m for two years and 3 deep (sea surface to 6000 m) profiling floats will be deployed, complemented by high-resolution hydrographic sections (including tracer analysis) across the mid-basin and the fracture zones. The in-situ observations will be paired with a state-of-art modeling component, which will be used to investigate the underlying dynamics and time evolution of the deep flow field. After validation using the new observational dataset, the model will be used to perform particle tracking simulations to answer some specific questions that are beyond the scope of the in-situ observations alone.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

深海通过与大气层交换热和化学化合物并在全球范围内将它们交换，从而在调节地球的气候中起着至关重要的作用。有时，地表水被带入最深的海洋区域，在这些海洋区域中，它们在长期与大气的进一步交流中被隔离，但是我们对水的移动方式的了解是不完整的。例如，二十年前，在印度洋西南亚的马达加斯加盆地，深水不受人类影响力的影响。但是，2018年的新测量结果显示了那里大量的人为化合物。这些惰性化合物从大气中进入海面的海洋，因此地表水下沉时，将这些化合物带到深海。仅仅二十年后，马达加斯加盆地中这种化合物的存在与我们先前对该地区的了解相反。一个可能的解释是，正如我们所理解的那样，在过去的二十年中，我们了解它们可能改变了过程和力量。为了解决这个难题，该项目将在三周的巡航过程中首次使用船舶仪器来测量该地区的深潮流，并采用两种类型的水内机器人技术来遵循几年的这些电流。将这些新颖的测量与计算机模拟相结合，这项研究将确定马达加斯加盆地深水传播的途径，并检查导致这种循环模式的原因。它将集中于从南极洲附近开始的水流，在那里，水沉没，通过大型海底山脉的裂缝进入马达加斯加盆地，然后是这些深水如何扩散以填充盆地。该项目的发现将解释为什么海洋的这一部分变化如此之快，推进了深海循环的知识，并有助于定义海洋中的热和化学化合物如何移动。拟议的研究将是美国对第二届国际印度洋探险队（IIOE-2）的贡献，并将在马达加斯加深层盆地中对深渊循环和温度变化的第一个直接估计。该项目将支持两名将被选为参加DMB巡游的本科生。 PIS还将在每年夏天在教育学生中主持和指导UCAR在大气研究和科学和伍兹孔合作伙伴关系方面的重要机会。 Scripps本科研究奖学金学生也将在每年夏天得到指导。此外，这次巡航将为印度洋社区提供，尤其是毛里求斯的海洋和学生，尤其是巡航的起点和终点端口。拟议的研究将调查在马达加斯加盆地（DMB）的深处深处的深渊循环中，大量的散布，在室内效应的横向散布和横向效应的横向散布的横向变化。主要目的是找出穿过西南印度山脊中深层断裂区域的年轻深渊水在盆地中蔓延开来，这对于更好地了解印度洋子午下的翻转循环及其可变性至关重要。为了确定盆地内部深渊水域的途径和转化，将部署75个浮子的压载阵列，在4000米处漂移两年，三年且深3（海面至6000 m）的浮雕将被部署，并通过中间基础和薄片ZONE的高分辨率水文切片（包括示踪剂分析）进行补充。原位观察结果将与最先进的建模组件配对，该组件将用于研究深流场的基本动力学和时间演变。在使用新的观测数据集进行验证之后，该模型将用于执行粒子跟踪模拟，以回答仅仅在原位观察结果范围之外的一些特定问题。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的审查标准来通过评估来支持的。

项目成果

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Impacts of ice-shelf melting on water mass transformation in the Southern Ocean from E3SM simulations

E3SM 模拟显示冰架融化对南大洋水团转化的影响

DOI：
10.1175/jcli-d-19-0683.1
发表时间：
2020
期刊：
Journal of Climate
影响因子：
4.9
作者：
Jeong, Hyein;Asay-Davis, Xylar S.;Turner, Adrian K.;Comeau, Darin S.;Price, Stephen F.;Abernathey, Ryan P.;Veneziani, Milena;Petersen, Mark R.;Hoffman, Matthew J.;Mazloff, Matthew R.
通讯作者：
Mazloff, Matthew R.

Zonal Distribution of Circumpolar Deep Water Transformation Rates and Its Relation to Heat Content on Antarctic Shelves

南极陆架环极深水转化率的地带性分布及其与热含量的关系

DOI：
10.1029/2022jc019310
发表时间：
2023
期刊：
Journal of Geophysical Research: Oceans
影响因子：
0
作者：
Narayanan, Aditya;Gille, Sarah T.;Mazloff, Matthew R.;du Plessis, Marcel D.;Murali, K.;Roquet, Fabien
通讯作者：
Roquet, Fabien

What Controls the Partition between the Cold and Warm Routes in the Meridional Overturning Circulation?

是什么控制着经向翻转环流冷暖路线的划分？