CO-ORDINATING AND PUMP-PRIMING INTERNATIONAL EFFORTS FOR DIRECT MONITORING OF ACTIVE TURBIDITY CURRENTS AT GLOBAL 'TEST SITES'

浑浊流是地球上最重要的泥沙输运过程。一股海底水流可以输送十倍于世界上所有河流的年泥沙流量，它们形成了地球上最大的泥沙堆积(海底风扇)。这些流动破坏了具有重要战略意义的海底电缆网络，这些网络承载着全球95%的数据流量，包括互联网和金融市场，并威胁到用于开采石油和天然气的昂贵的海底基础设施。古老的水流在世界各地形成了许多深水地下油气藏。发人深省的是，我们从海底流动中获得的直接测量数据是如此之少，这与河流等其他主要泥沙输送过程形成了鲜明对比。泥沙浓度是记录浑浊流的最基本参数，对于到达海底扇的水流，从来没有测量过泥沙浓度。那么，我们如何知道在水槽水池中建立哪种类型的流动模型，或者使用哪些假设来制定数值或分析模型？如果我们要逐步改变理解，就迫切需要直接监测流动。流发生了显著的变化，因此需要从源到宿数据，我们需要监视不同设置中的流，因为它们的特征可能会有很大差异。该项目将协调和推动国际努力，以监测实际行动中的浑浊水流。工作将集中在捕捉主要类型的流和触发器的关键“测试地点”。其目标是在关键地点建立完整的从源到汇的信息，而不是在不同的地点产生更多不完整的数据集。试验点选择在已知流量活跃的地方--每年或更短的时间尺度上发生，以前的工作为未来的项目提供基础，以及可以进入合适的基础设施(例如船只)。最初的试验点包括由河流注入的浑浊水流系统，河流进入海水或淡水的地方，以及经常发生或没有暴跌的河流洪水的地方。它们还包括产生强大水流到达深海并建造潜艇风扇的地点。该项目之所以新颖，是因为还没有为监测浑浊洋流建立类似的网络，因此还需要建立数值和实验室模型来了解实地观测的意义，我们的目标也是让模型师参与监测数据集的设计和分析。这项工作也将有助于检验各种类型模型的有效性。我们将收集沉积物岩心和地震数据，以研究系统的较长期演化，以及较罕见的流动类型。对于露头和地下油气藏地质学家来说，了解沉积物与流动的联系是很重要的。这一建议是及时的，因为最近努力开发新的流动监测技术，这一技术前景广阔。之所以需要这套新技术，是因为浑浊水流的威力非常大(高达20米/S)，会摧毁放置在海底传统系泊设备上的传感器。这包括新的传感器，将这些传感器放置在活跃流动上方或近床层的新方法，以及通过自动滑翔机恢复数据的新方法。一些试验场缺乏关键的初步数据，如详细的水深底图或地震数据集。我们的最终目标是填补现场调查数据中的关键空白，以便在未来提交更大规模的监测项目。这个项目将为现有的2014-2017年监测蒙特利峡谷流量的NERC补助金和由海底电缆运营商主办的NERC行业联谊会增加相当大的价值。Tling是两项NERC标准拨款、一项NERC行业奖学金和NERC研究计划联盟奖的PI。他也是NERC中心的一部分，因此符合该计划的所有四个标准。

Turbidity currents are the volumetrically most import process for sediment transport on our planet. A single submarine flow can transport ten times the annual sediment flux from all of the world's rivers, and they form the largest sediment accumulations on Earth (submarine fans). These flows break strategically important seafloor cable networks that carry > 95% of global data traffic, including the internet and financial markets, and threaten expensive seabed infrastructure used to recover oil and gas. Ancient flows form many deepwater subsurface oil and gas reservoirs in locations worldwide. It is sobering to note quite how few direct measurements we have from submarine flows in action, which is a stark contrast to other major sediment transport processes such as rivers. Sediment concentration is the most fundamental parameter for documenting what turbidity currents are, and it has never been measured for flows that reach submarine fans. How then do we know what type of flow to model in flume tanks, or which assumptions to use to formulate numerical or analytical models? There is a compelling need to monitor flows directly if we are to make step changes in understanding. The flows evolve significantly, such that source to sink data is needed, and we need to monitor flows in different settings because their character can vary significantly. This project will coordinate and pump-prime international efforts to monitor turbidity currents in action. Work will be focussed around key 'test sites' that capture the main types of flows and triggers. The objective is to build up complete source-to-sink information at key sites, rather than producing more incomplete datasets in disparate locations. Test sites are chosen where flows are known to be active - occurring on annual or shorter time scale, where previous work provides a basis for future projects, and where there is access to suitable infrastructure (e.g. vessels). The initial test sites include turbidity current systems fed by rivers, where the river enters marine or freshwater, and where plunging ('hyperpycnal') river floods are common or absent. They also include locations that produce powerful flows that reach the deep ocean and build submarine fans. The project is novel because there has been no comparable network established for monitoring turbidity currentsNumerical and laboratory modelling will also be needed to understand the significance of the field observations, and our aim is also to engage modellers in the design and analysis of monitoring datasets. This work will also help to test the validity of various types of model. We will collect sediment cores and seismic data to study the longer term evolution of systems, and the more infrequent types of flow. Understanding how deposits are linked to flows is important for outcrop and subsurface oil and gas reservoir geologists.This proposal is timely because of recent efforts to develop novel technology for monitoring flows that hold great promise. This suite of new technology is needed because turbidity currents can be extremely powerful (up to 20 m/s) and destroy sensors placed on traditional moorings on the seafloor. This includes new sensors, new ways of placing those sensors above active flows or in near-bed layers, and new ways of recovering data via autonomous gliders. Key preliminary data are lacking in some test sites, such as detailed bathymetric base-maps or seismic datasets. Our final objective is to fill in key gaps in 'site-survey' data to allow larger-scale monitoring projects to be submitted in the future.This project will add considerable value to an existing NERC Grant to monitor flows in Monterey Canyon in 2014-2017, and a NERC Industry Fellowship hosted by submarine cable operators. Talling is PI for two NERC Standard Grants, a NERC Industry Fellowship and NERC Research Programme Consortium award. He is also part of a NERC Centre, and thus fulfils all four criteria for the scheme.