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

爆炸性喷发产生的火山羽流对健康、环境和经济构成全球性危害。空中火山灰对航空业造成的破坏有据可查，并可能产生严重的经济影响。因此，预测含灰羽流的范围和演化对危害评估至关重要。然而，数值羽流模型的准确性目前受到输入喷发参数或“源项”的不确定性的限制，这些参数描述了大气中灰烬的初始分布。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最先进的火山羽流卫星观测来改进源项参数的估计。将这种方法应用到最近火山喷发的数据中，将对羽流在分散过程中是如何演变的，以及所涉及的过程，如颗粒沉积和聚集，提供关键的见解。我们目前还没有在关键源区观测这些过程的技术，而这种实时数据将是灰危害预测的转换。为了解决这个问题，我们提出多频雷达作为一种强大的新型测量工具，能够提供描述粒径分布和质量负载的关键源项参数。我们将利用实验室实验和先进的羽流数值模拟来开发和展示这种技术的潜力。结果将立即与目前用于观测羽流的现有单频雷达系统相关，并将为下一代多频系统的设计和部署提供信息。这个项目是火山学家、大气和雷达物理学家和气象学家之间的合作，他们是实验室实验、遥感、环境系统不确定性和数值模拟方面的专家。通过与英国气象局的直接合作，我们将把对不确定性的理解提高到一个新的水平，从而实现可操作的远程空中火山灰浓度预测。研究结果将为国际工作人员在火山羽流预测和危害评估方面带来巨大的好处，并将为接近实时的三维量化火山羽流过程打开大门。对大气中火山灰扩散的更准确预测，将有助于更好地减轻对健康的影响、对基础设施的破坏、农业污染和航空危害，从而产生重大的、与全球相关的社会、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.