1. Support to Aviation Control Service Jos van Geffen, Michel Van Roozendael, Isabelle De Smedt, Caroline Fayt (BIRA-IASB) Walter Di Nicolantonio, Giovanni Ballista, Alessandra Cacciari (CGS) Pieter Valks, Diego Loyola, Thilo Erbetseder (DLR) Ronald van der A (KNMI) TEMIS User Workshop – 8-9 October 2007 ESA/ESRIN, Frascati, Italy

2. Contents Background and Users of the Service Structure of the Service Examples Concluding remarks Eruption of the Grímsvötn volcano on Iceland in November 2004; photo by Matthew J. Roberts

3. Volcanic eruptions and aviation Volcanic clouds can contain: – Rock fragments, fine particles (ash). – Corrosive gases (incl. SO2), water vapour. Hazard to aviation: ash (major) and SO2. More than 90 aircraft damaged by ash clouds: – At least 7 cases of in-flight loss of power. – Three 747’s lost all engines (Indonesia 1982, Alaska 1989). – Pinatubo: aircraft damaged > 1000km from eruption. On average 10 eruptions per year reach flight levels. Economic cost estimation of US$ 250 Million between 1982-2000. Avoidance of ash clouds is the only safe procedure for the aircraft. sheet info: thanks to Claire Witham, UK Met Office / London VAAC

4. Aim and users of the service The aim of the Support to Aviation Control Service (SACS) is to deliver in near-real-time data derived from satellite measurements regarding SO2 and aerosol emissions possibly related to volcanic eruptions, and where possible to track volcanic plumes. The Volcanic Ash Advisory Centres (VAACs) are the official organisations to gather information on volcanic ash clouds and on the basis of that issue advices and alerts to air line and air traffic control organisations on the possible danger of volcanic clouds. Notifications of “exceptional SO2 concentrations” and data from SACS can assist the VAACs with their task: to assess volcanic activity and if necessary to issue alerts to air traffic control and airline organisations. Key users: the Toulouse and London VAACs.

5. The VAACs The VAACs are part of an international system set up by the International Civil Aviation Organization (ICAO) called the International Airways Volcano Watch (IAVW), which was founded at an ICAO meeting in 1995. VAAC responsibilities to aviation users include: Utilise satellite data, pilot reports, etc. to detect and track ash clouds. Use trajectory/dispersion models to forecast the motion of ash plumes.

6. Structure of the service http://www.temis.nl/aviation/so2.php

7. Predefined regions Default maps are made for the world, plus: 42 volcano regions of 30 by 30 degrees 11 air quality regions of 40 by 40 degrees

8. Example: Southern Africa Data available as: Daily orbit coordinates 1-day gridded data 3-day composite Monthly average

9. Example of a notification SACS notification of exceptional SO2 concentration ================================================== Process date : 2007 08 27 Process time : 06:30:01 CEST Instrument : SCIAMACHY No. notices : 1 Alert notice : 1 -------------------- Volcano reg. : 26 Kurile Islands Volcano reg. : 27 Kamchatka Peninsula http://www.oma.be/BIRA-IASB/Molecules/SO2nrt/alert/?alert=2007... Start date : 2007 08 27 Start time : 00:25:42.712 UTC Aver. long. : 156.4 deg. Aver. latit. : 55.0 deg. Aver. sza : 47.2 deg. Max. SO2 scd : 7.2 DU SO2 vcd @ max: 2.4 DU Cloud data : used for vcd...

12. Example of a notification The criteria for an alert are based on the SO2 slant column values. Reports mention activities of some volcanoes on the Kamchatka Peninsula and on the Kuril Islands at the end of August: SHIVELUCH 56.65°N, 161.36°E summit elev. 3,283 m KARYMSKY 54.05°N, 159.43°E summit elev. 1,536 m CHIKURACHKI 50.33°N, 155.46°E summit elev. 1,816 m

13. Piton de la Fournaise – SCIA

14. Piton de la Fournaise – OMI / GOME-2

15. Volcanic aerosols from SEVIRI Etna on 14 July 2006 at 05h, 06h and 10h UTC (BTD technique) Etna on 22 July 2006 at 05h, 06h and 10h UTC

16. Trajectory analysis SO2 peak west of Hawaii : from Anatahan (788 m), emitted 4 days before? Depending on the intitial height of the backward trajectories, the SO2 could have come from “anywhere” → must be careful !!

17. Eruption of Jebel at Tair (Yemen) Eruption: evening of 30 Sept. 2007. SO2 alerts issued on 01 Oct. and later. Toulouse VAAC: no ash cloud visible. 3-km long island in the Red Sea; last eruption: 1883.

18. Eruption of Jebel at Tair (Yemen) OMI – KNMI/NASA/NIVR

19. Eruption of Jebel at Tair (Yemen)

20. Recent web statistics Sep | Oct

21. Concluding remarks The service is set up using SCIAMACHY data: suitable for testing. The processing and analysis works fine, though some problems remain, in particular retrieval at high solar zenith angle and artifacts due to the South Atlantic Anomaly. SO2 released by volcanic eruptions (and anthropogenic activities) clearly detected in several cases and alerts were sent. Experience of the key users so far is that the service does provide an additional source of information for the VAAC’s tasks, despite the poor geographic and temporal coverage of SCIAMACHY. Major improvements are expected once OMI and GOME-2 data is included, due to the high spacial resolution of OMI and because GOME-2 measures in the morning and OMI early afternoon. http://www.temis.nl/aviation/so2.php