Operations of VAAC. before/after Eyjafjalla2010. ESA / EUMESAT Workshop on Eyjafjalla eruption and ash monitoring from space.

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1 Operations of VAAC before/after Eyjafjalla2010 ESA / EUMESAT Workshop on Eyjafjalla eruption and ash monitoring from space Philippe Husson

2 IAVW : 9 V A A C T.J Casadevall,., T. B Thompson,., and T. Fox / ICAO. 9 VAACs designed by ICAO to monitor satellite data and run dispersion models as to issue advisories in text and graphic format.

3 V.A.G. Chart without quantitative value : The area depicted is a VAAC expertise about the area observed and forecast where airspace is contaminated by presence of volcanic ash. What is out of bounds is safe.

4 ICAO WARNING PROCEDURES MWO ATS/AIS VAAC NOF CFMU AOC DETECTION Volc Obs.

5 ICAO ANNEX3 STANDARDS A VAAC shall.. respond to a notification that a volcano has erupted, or is expected to erupt or volcanic ash is reported in its area of responsibility, by : a) monitor relevant geostationary and polar-orbiting satellite data to detect the existence and extent of volcanic ash in the atmosphere in the area concerned; b) activate the volcanic ash numerical trajectory/dispersion model in order to forecast the movement of any ash cloud which has been detected or reported; c) issue advisory information regarding the extent and forecast movement of the volcanic ash cloud

6 VAACs use two tools : - Dispersion models METHODOLOGY BEFORE 20 APRIL - Satellite imagery to calibrate the dispersion models in a qualitative way (expertise is on VAAC s forecaster). In case of weak eruptions (flow plume top and/or short duration), only the observation is used Whenever no image is available, dispersion models are solely used this case is the worst for realism in the area depicted as contaminated area. (cf eruption of Grimsvötn -Nov 2004)

7 DISPERSION FORECAST MOCAGE (accident version) VOLCAN used by the Toulouse VAAC integers Transport by winds Dispersion by turbulence Wash out by clouds, rain-out by precipitations Sedimentation by gravity

8 (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) V O N A (2) Issued /0855Z (3) Volcano: Água de Pau (4) Current Aviation Color Code: RED (5) Previous Aviation Color Code: RED (6) Source: CVARG (Centre of Volcanology and Geological Risks Assessment) (7) Notice Number: 2008/003 (8) Volcano Location: 3746N02528W (9) Area: Azores and Madeira (10) Summit Elevation: 0947 m (3107 ft) (11) Volcanic Activity Summary:. A new explosive eruption at Água de Pau volcano has started approximately at 0845Z and keeps ongoing. This follows the increase in eruptive activity started yesterday, November 5th. Seismic activity remains at high levels. (12) Volcanic Cloud Height: The height of the ash cloud is estimated up to m (50000 feet) above sea level, based on ground observations. (13) Other Volcanic Cloud Information: Preliminary height up to15000 m (50000 feet) above sea level. (14) Remarks: NIL (15) Contacts: Volcano observatory Coordinator Tel: / ; Fax (16) Next Notice A new VONA will be issued when conditions at the volcano warrant changing the aviation color code or when a significant volcanic event occurs within the current color code.

9 Volcanic report

10 DISPERSION FORECAST

11 Models intercomparaison Based on the same source term : The physical process in models are quite comparable and the consistency between weather numerical prediction is generally good.

12 USE OF SATELLITE DATA BY THE VAAC Provides qualitative data About the eruption About volcanic ash cloud Geostationaries allows loops and are a familiar tool for weather forecasters. The apparent flow (direction and speed) can be used to determine the average level of the layer In case of partial or temporary mask by water/ice cloud, flow can be used to provide consistency. MSG Envisat NOAA16

13 SATELLITES GEOSTATIONNAIRES DUST RGB PRODUCT AVAILABLE ON THE VAAC FORECASTER S WORKING STATION

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15 What has changed since April 20 A threshold of concentration of volcanic ash possibly damageable for jet engines has been provided by engine industry. Tests should be probably conducted in wind tunnels with volcanic ash on engines to confirm this number. Dispersion models for volcanic ash therefore can be used no longer in relative but in absolute terms without necessary reference to the observation satellite The uncertainty on the values provided by volcanologists to initialize dispersion models (an order of magnitude, according to them), however, lead to uncertainty of the same value in the depiction of concentration maps provided by these models.

16 Cartes de concentrations Valeurs connues pour avoir entraîné des calages moteurs d un B747 de KLM : 2g/m3

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18 CONCLUSION - QUESTIONS - Now that operators and regulators require quantitative data, how may be used forecasters expertise? (how qualitative may correct quantitative?) - What about the numerous non monitored volcanoes for which no data will be available in real time? - How to estimate the uncertainty in the source term of models (mass rate)? Once known, how to reduce it? - Impact on airlines operations are very level dependant. How to improve the vertical information about presence and concentration?

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