As part of an ESA initiative to enhance the use of Earth Observation (EO) data in volcanic ash monitoring and forecasting, the project VAST (Volcanic Ash Strategic-initiative Team) was set up. VAST aims at demonstrating the suitability of EO data for these types of activities, and improve on the existing monitoring and forecasting services for ash transport and its interaction with aviation. With the VAST project the following targets for service improvement will be addressed:
- Access to EO data sources for volcanic plume observations.
- Consolidation of EO observations and other ground-based data for characterizing volcanic ash clouds.
- Development of operational volcanic ash products from EO data using advanced retrieval algorithms.
- Further development of dispersion forecast models (global and regional) including data assimilation, inverse modelling, and ensemble techniques to generate a measure of uncertainty of the forecast.
- Availability of real-time monitoring (including satellite data) of the dispersion processes, which is fundamental for the confirmation (validation) or confutation (verification) of model predictions.
- Performance of periodic model inter-comparison/evaluation exercises on volcanic eruptions that should involve VAACs, meteorological services, volcano observatories and other volcanology institutes with operational forecasting capabilities in Europe that are used in support of decision making at the national level.
MOTIVATION FOR THE PROJECT
In April and May 2010, large parts of the European airspace were shut down for several days as a consequence of the eruption of the volcano Eyjafjallajökull in Iceland. The total financial impact of the event has been estimated at € 5 billion (Oxford Economics, 2010). The significant economic impact and public awareness of these air traffic restrictions raised the need to promote initiatives aimed at improving the management of volcanic eruptions in the context of civil aviation. Besides the aviation issues, volcanic ash can, on a larger scale, also affect human health and agriculture.
Looking into a broader context, there are a variety of possible large-scale, trans-boundary emergency scenarios caused by the injection of material into the atmosphere. The injections may be due to natural processes or technical/industrial accidents. The key to the management of all such scenarios is provided by meteorology and atmospheric transport simulations. Without these technologies, the impacts of such events could neither be predicted nor assessed, making the subsequent management of the situation almost impossible.
The problem of transport of ash and its interaction with aviation is a global problem (Prata, 2008), and requires a global approach. Satellite data (earth observation data, referred to hereafter as EO data) is best suited for ash detection and observation because of its global perspective, timeliness and in the case of volcanoes because it presents no risk during acquisition.
Most members of this consortium have been working in the volcano eruption and ash prediction area for many years, and are very experienced in this field. The main motivation of the VAST project is to make use of and integrate the additional experiences gained during the Eyjafjallajökull eruption, and to propose a new sustainable and decentralized service that builds on and adds value to existing services and infrastructures, existing cooperation mechanisms, existing earth observation and in-situ data, and last but not least on the existing Volcanic Ash Advisory Centres (VAACs) established under the umbrella of ICAO/WMO.
SCIENTIFIC AND TECHNICAL BACKGROUND
For decades, volcanic ash has been understood to pose a serious hazard to aviation (e.g., Dunn and Wade, 1994; Miller and Casadevall, 2000; Guffanti and Miller, 2002). From 1973 through 2000, about 100 encounters of aircraft with airborne volcanic ash have been documented. In the same time period, ash falls have forced closures or have severely impacted operations at more than 40 airports in 15 countries.
A recent Special Issue in the journal Natural Hazards summarizes the state of the science of the volcanic ash/aviation problem (Prata and Tupper, 2009). On average, somewhere on Earth, there is about one volcano each week that emits ash and gases into the atmosphere with the potential to intersect aviation airspace.
Volcanoes can eject large amounts (~1-50Tg) of ash and gases high (>20 km) into the atmosphere and thus intersect airspace from the ground up to jet aircraft cruising altitudes (>40,000 ft).