Radar-supported Next-Generation Forecasting of Volcanic Ash Hazard (R4AsH)

火山喷发产生的火山羽流对健康、环境和经济构成全球危害。空中火山灰对航空造成的破坏是有据可查的，并可能产生严重的财务影响。因此，预测富含火山灰的羽流的范围和演化对于危险评估至关重要。然而，目前数值烟羽模型的准确性受到描述大气中火山灰初始分布的输入喷发参数或源项的不确定性的限制。我们将开发一种新的方法，通过结合先进的数值模型、理解不确定性的技术和对火山羽流的最新卫星观测来改进源项参数的估计。将这种方法应用于最近喷发的数据，将提供至关重要的洞察，了解羽流在分散时如何演变，以及涉及的过程，如粒子沉淀和聚集。我们目前还没有在临界源项区域观察这些过程的技术，这种实时数据将对灰烬危险预测产生重大影响。为了解决这一问题，我们提出了多频雷达作为一种强大的新的测量工具，能够提供描述颗粒尺寸分布和质量负载的关键源项参数。我们将使用实验室实验和先进的羽流数值模拟来开发和演示这项技术的潜力。研究结果将与目前用于观测羽流的现有单频雷达系统立即相关，并将为下一代多频系统的设计和部署提供信息。该项目是火山学家、大气和雷达物理学家以及气象学家的合作项目，他们在实验室实验、遥感、环境系统的不确定性和数值模拟方面都是专家。通过直接与英国气象局合作，我们将把不确定性理解提高到可操作的远程气载火山灰浓度预测的新水平。这一结果将对国际工作人员在火山羽流预报和危险评估方面大有裨益，并将为近实时地对羽流过程进行3D量化打开大门。更准确地预测火山灰在大气中的扩散将有助于改善对健康影响、基础设施破坏、农业污染和航空危害的缓解，从而产生重大的全球相关的社会、环境和经济影响。

Volcanic plumes from explosive eruptions present a global hazard to health, the environment and the economy. The disruption caused by airborne ash to aviation is well documented and can have serious financial repercussions. Consequently, forecasting the extent and evolution of ash-rich plumes is vital for hazard assessment. However, the accuracy of numerical plume models is currently limited by uncertainties in the input eruption parameters, or 'source term', that describe the initial distribution of ash in the atmosphere.We will develop a new approach to improve estimates of source term parameters by combining advanced numerical models, techniques for understanding uncertainty and state-of-the-art satellite observations of volcanic plumes. Applying this method to data from recent eruptions will provide critical insight into how plumes evolve as they are dispersed, and into the processes involved, such as particle sedimentation and aggregation. We currently have no technique for observing these processes in the critical source term region, and such real-time data would be transformational for ash hazard forecasting. To address this, we propose multi-frequency radar as a powerful new measurement tool capable of providing the key source term parameters that describe particle size distribution and mass loading. We will develop and demonstrate the potential of this technique using laboratory experiments and advanced numerical simulations of plumes. The results will be immediately relevant to existing single-frequency radar systems currently used to observe plumes, and will inform the design and deployment of next-generation multi-frequency systems.This project is a collaboration between volcanologists, atmospheric and radar physicists and meteorologists, who are expert in laboratory experiments, remote sensing, uncertainty in environmental systems and numerical modelling. By working directly with the UK Met Office, we will deliver a new level of uncertainty understanding into operational long-range airborne ash concentration forecasts. The results will be of enormous benefit to international workers in volcanic plume forecasting and hazard assessment, and will open the door to near-real-time 3D quantification of plume processes. More accurate forecasts of the dispersal of ash in the atmosphere will enable improved mitigation for health effects, infrastructure damage, agricultural contamination and aviation hazards to deliver significant and globally relevant social, environmental and economic impacts.