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

Lead Research Organisation: University of St Andrews
Department Name: Physics and Astronomy

Abstract

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.

Planned Impact

Our main goal is to improve Volcanic Ash Transport and Deposition Models (VATDMs) of dispersing volcanic plumes, by explicitly tackling the "most pressing challenge" for accurate hazard forecasting - a better characterisation of the eruption source term. The project will enable improved operational ash forecasts, thus resulting in academic, societal and economic impact with global reach.

Improved VATDMs will increase the effectiveness of operational public services such as the UK Met Office, VAACs, CAA (in the UK), the US Geological Survey (USGS) and civil defence organisations and disaster emergency response organisations worldwide. Improved models will enhance disaster planning through scenario-testing simulations (for volcanic and other plumes, e.g. from forest fires). This will lead to improved mitigation of volcanic ash hazards such as air/water pollution, agricultural contamination and infrastructure damage, and potentially to policy changes such as ICAO operational procedures for air traffic operations near volcanic eruptions. Building capability for improved operational ash forecasts will minimise disruption and optimise the mitigation response to volcanic plumes internationally. With air travel continuing to increase, and economic losses due to airspace closure from the 2010 Eyjafjallajökull eruption estimated at US$5B, this is a key economic driver, for the UK and worldwide; optimised responses will minimise economic loss at the international scale, reduce economic impact on individual businesses at national scale, and reduce impact on individuals at the local scale.

In the longer term, we will deliver impact through our multi-frequency radar technique enabling 3D plume imaging and providing critical data needed to understand the processes occurring within evolving plumes (e.g. particle aggregation) and to develop the next generation of VATDMs. However, our results, inversion strategies and retrieval algorithms will be of immediate relevance to meteorologists and other atmospheric and remote sensing scientists researching particulates in the environment, including dust and smoke plumes from forest fires. Our results will also guide use of existing radar systems for better determining plume properties, and will inform the development and acquisition of new systems, with implications for radar researchers, manufacturers and operational users. Our new characterisation of ash scattering properties will enable immediate improvement of current radar interpretations to deliver more accurately defined volcanic plume source term parameters, and thus improved VATDM outputs. The transfer of our multi-frequency retrieval algorithms to operational use would be a successful exploitation of scientific knowledge.

The project will develop five PDRA researchers, some of whom already demonstrate accomplished profiles, into leading young researchers with cross-disciplinary skills in hazard modelling and remote sensing of atmospheric particulates. With a network of international academic and applied (i.e. operational) collaborators, they will represent a body of expertise uniquely placed to make a substantial contribution to UK and global geohazard resilience, as well as to other areas of science.

Through outreach work, the project will increase public understanding of the internationally leading research being conducted in the UK. Outreach will be focussed on delivering a better understanding of the hazards and risks associated with ash clouds so that the importance of improved accuracy of ash forecasts is appreciated. Our project embeds links with VAACs who are responsible for aviation hazard forecasting and the USGS, with their connections to national public policy and management of natural hazards, to ensure that the research benefits to society will be realised globally.
 
Description We have built a triple-frequency radar to measure falling volcanic ash in the laboratory, using a fall chamber developed by Lancaster University. The aim is to prove the principle that multi-frequency radar is a technique that could remotely measure the concentration and particle sizes in an ash plume (the 'source term') which currently can not be achieved in the field with existing instrumentation. This information would significantly improve hazard warning for aviation after an eruption as current methods have to use assumed rather than measured values for the source term, which are inevitably inaccurate. Ash dispersal models predict where ash is transported through the atmosphere so providing them with better estimates of the source term will increase the accuracy of their predictions.
The radar instrument has been carefully calibrated with test targets and performs consistently. The radar and chamber have been used to compare the measured radar reflectivity of ash against theoretical predictions. Work is ongoing to close this loop which depends heavily on the ground-truth optical measurements of the in-flight ash particles that are subject to significant fluctuations.
Exploitation Route Lancaster now has a unique measurement facility to investigate the properties of streams of falling particles which could be of interest to users beyond volcanology. Discussions are underway with a German University to make use of the chamber and extend its capabilities to investigate particle aggregation processes. A PhD project based around using the chamber and analysing the data is currently advertised from Lancaster. Our experience in developing this radar has strongly influenced the design of a new instrument currently under development in another NERC grant for characterising th4e scattering properties of snowfall.
Sectors Aerospace

Defence and Marine

Environment

 
Description Collaboration with Lancaster University 
Organisation Lancaster University
Department Lancaster Environment Centre
Country United Kingdom 
Sector Academic/University 
PI Contribution We developed advanced radar hardware for making laboratory measurements of falling volcanic ash. The radar worked with a fall chamber designed and built by Lancaster.
Collaborator Contribution Lancaster developed the ash fall chamber and provided overall direction to meet volcanology objectives.
Impact This project has been inter-disciplinary, spanning earth sciences (volcanology) and physics/engineering (radar development). UStA led 2 conference publications from this work and we contributed to 1 jorunal publication led by Lancaster.
Start Year 2019
 
Description Participation in workshop on volcanic eruptions 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact A 2-day workshop was held at Lancaster University in July 2023 to showcase the research conducted in the R4AsH and V-PLUS NERC Highlight Topic projects which related to the monitoring and understanding of volcanic plumes and the transport of ash and gases through the atmosphere which cause hazards to aviation, agriculture and health. The international audience included representatives of the Volcanic Ash Advisory Centres (VAACs), the US Geological Survey, Rolls-Royce, the Met Office, and from Universities and research centres across 4 European countries as well as the UK. The meeting included talks, posters, lively discussion sessions, tours of the ash fall chamber and radar equipment, and a panel session to discuss future opportunities.
Year(s) Of Engagement Activity 2023