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

浊度流是我们这个星球上泥沙运输的体积上最重要的过程。一条海底流可以运送十倍于世界上所有河流的年沉积物通量，它们形成了地球上最大的沉积物堆积（海底扇）。这些流破坏了具有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海底基础设施。古流体在世界各地形成了许多深水地下油气藏。值得注意的是，我们对海底流动的直接测量非常少，这与其他主要的沉积物运输过程（如河流）形成鲜明对比。沉积物浓度是记录浊度流的最基本参数，但从未测量过到达海底风扇的水流。那么我们如何知道在水槽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？如果我们要在理解上做出阶段性的改变，就迫切需要直接监控流程。流的发展非常显著，因此需要从源到汇的数据，并且我们需要在不同的设置中监视流，因为它们的特征可能会有很大的变化。该项目将协调和推动国际上监测实际浊度流的努力。工作将集中在捕获主要类型的流和触发器的关键“测试站点”上。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。测试地点被选择在已知流量是活跃的地方——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了基础，并且可以访问合适的基础设施（例如船只）。最初的试验点包括由河流提供的浊流系统，在那里河流进入海洋或淡水，以及在那里经常发生或不存在汹涌的河流洪水。它们还包括产生强大气流的地点，这些气流到达深海并形成海底风扇。该项目是新颖的，因为还没有建立监测浊度流的可比较网络。数值和实验室建模也需要了解现场观测的意义，我们的目标也是让建模人员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，以研究系统的长期演变，以及更不常见的流动类型。对于露头和地下油气储层地质学家来说，了解矿床与流动之间的联系非常重要。这项建议是及时的，因为最近努力开发监测流量的新技术，前景广阔。这一套新技术是必要的，因为浊流可能非常强大（高达20米/秒），会破坏放置在海底传统系泊处的传感器。这包括新的传感器，将传感器放置在活动流层或近层层上的新方法，以及通过自动滑翔机恢复数据的新方法。一些试验点缺乏关键的初步数据，例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，以便将来提交更大规模的监测项目。该项目将为现有的NERC赠款（2014-2017年监测蒙特雷峡谷的流量）和由海底电缆运营商主办的NERC行业奖学金增加相当大的价值。taling是两项NERC标准补助金、一项NERC行业奖学金和NERC研究计划联盟奖的PI。他也是NERC中心的一员，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.