Comparison of Deepglider and RAPID-MOCHA Moored Array Observations

Deepglider 和 RAPID-MOCHA 系泊阵列观测的比较

• 批准号: 1458174
• 负责人: Charles Eriksen
• 金额: $ 108.57万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-03-01 至 2018-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1458174&HistoricalAwards=false
• 关键词: Comparison; Deepglider; RAPID; MOCHA; Moored

The Atlantic Meridional Overturning Circulation (AMOC) is a principal element of the global climate system. At 26.5 degrees North latitude, the AMOC is responsible for carrying about sixty percent of the net poleward heat flux carried by the oceans and about thirty percent of the total heat flux carried by the atmosphere and ocean together, integrated zonally around the globe. Through sea surface temperature modulation, the AMOC is linked to climate signals on interannual to multi-decadal time scales that can have extensive societal impact. Climate models predict substantial weakening of the AMOC over the next century, a change with potentially wide ramifications. For the past decade, U.S. and U.K. scientists have maintained a transatlantic heavily instrumented moored array to observe fluctuations in the AMOC and its heat flux. Variability on time scales longer than ten days is dominated by geostrophic current fluctuations inferred from transatlantic dynamic height differences and boundary current fluctuations. While effective, the moored array is costly to maintain. This project is an attempt to assess the effectiveness of very long-range full ocean depth underwater gliders in measuring aspects of the AMOC side-by-side the moored array. These autonomous vehicles, named Deepgliders, collect sea-surface to sea-floor profiles of temperature, salinity, and dissolved oxygen along slanting trajectories through the ocean in near-real time. They also return estimates of the full-depth average current. Successful application of Deepgliders to the 26.5 degrees North latitude line will motivate applying the technique to other transects of interest (such as in the North Atlantic subpolar gyre and the South Atlantic subtropical gyre), to address the challenges of repeat hydrography globally, and reduce the overall cost of such programs in order that such ocean climate projects can be afforded as a whole by funding agencies. These together will lead to deeper understanding of earth?s climate.The overall goal of the project is to learn how to assist the sustainable continuation of AMOC monitoring through coming decades. Learning to measure the AMOC using Deepgliders will help sustain operation of the current array at 26.5 degrees North for the many decades required to resolve interannual and multi-decadal variability. Only by operating for several decades will the signals associated with natural climate variability and anthropogenic climate change be evident and potentially distinguishable. A Deepglider is designed to make about 250 dives to as deep as 6000 m in missions lasting as long as 18 months while traveling as much as 10,000 km through the ocean on a single set of lithium batteries. It samples temperature, salinity, and dissolved oxygen along saw tooth paths through the ocean and communicates them to shore each time it reaches the sea surface via satellite telemetry. Two-way communication allows commands to be transmitted to Deepgliders so that its autonomous behavior can be controlled remotely from a pilot anywhere with an internet connection. As a pilot experiment, four one-year Deepglider missions are planned over a 2-year period overlapping moored deployments. Two of these will concentrate on maintaining position close to a RAPID-MOCHA mooring just offshore Abaco, Bahamas to resolve the principal variability in dynamic height for use in estimating the interior ocean contribution to AMOC variability. Two more will repeat a short section intended to capture temporal and spatial variations in Antilles and Deep Western Boundary Current flow. Deepglider and moored measurements will be compared to assess relative efficacy.

大西洋经向翻转环流（AMOC）是全球气候系统的主要组成部分。在北纬26.5度，AMOC负责携带大约60%的海洋携带的净极向热通量，以及大约30%的大气和海洋一起携带的总热通量，围绕地球仪进行纬向整合。通过海洋表面温度调制，AMOC与年际到数十年时间尺度上的气候信号联系起来，可以产生广泛的社会影响。气候模型预测，在下一个世纪，AMOC将大幅减弱，这一变化可能会产生广泛的影响。在过去的十年里，美国和英国科学家们在大西洋两岸维持了一个装有大量仪器的系泊阵列，以观察AMOC及其热通量的波动。大于十天的时间尺度上的变化主要由从跨大西洋动力高度差和边界流波动推断的地转流波动决定。虽然有效，但系泊阵列的维护成本很高。该项目试图评估超远程全海洋深度水下滑翔机在测量AMOC并排系泊阵列方面的有效性。这些名为Deepgliders的自动驾驶车辆几乎实时地沿着倾斜的轨迹收集海面到海底的温度，盐度和溶解氧的剖面。它们还返回全深度平均海流的估计值。Deepgliders在北纬26.5度线的成功应用将推动将该技术应用于其他感兴趣的断面（例如北大西洋亚极地环流和南大西洋亚热带环流），以应对全球重复水文的挑战，并降低此类计划的总体成本，以便这些海洋气候项目可以作为一个整体由资助机构提供。这些加在一起会让我们对地球有更深的了解吗？该项目的总体目标是了解如何在未来几十年内协助AMOC监测的可持续性。学习使用Deepgliders测量AMOC将有助于维持当前阵列在北纬26.5度的操作，以解决年际和数十年变化所需的几十年。只有经过几十年的运行，与自然气候变率和人为气候变化相关的信号才能明显并可能区分开来。Deepglider的设计目的是在长达18个月的任务中进行约250次潜水，最深可达6000米，同时在一组锂电池上在海洋中行驶多达10，000公里。它沿着沿着锯齿状的路径在海洋中采集温度、盐度和溶解氧的样本，并在每次到达海面时通过卫星遥测将这些数据传送到海岸。双向通信允许将命令传输到Deepgliders，以便可以通过互联网连接从任何地方的飞行员远程控制其自主行为。作为一项试点实验，计划在两年的时间内进行四次为期一年的Deepglider任务，重叠停泊部署。其中两个将集中在保持位置接近快速-MOCHA系泊就离岸阿巴科，巴哈马，以解决动态高度的主要变化，用于估计内部海洋的AMOC变异的贡献。另外两个将重复一个简短的部分，旨在捕捉安的列斯群岛和深层西边界电流流动的时间和空间变化。将比较Deepglider和系泊测量值，以评估相对有效性。