APPLICATIONS OF METEOSAT SECOND GENERATION (MSG)

1. APPLICATIONS OF METEOSAT SECOND GENERATION (MSG) VOLCANIC ASH & SO2 DETECTION Authors: J. Kerkmann (EUMETSAT), B. Connell (CIRA) jochen.kerkmann@eumetsat.int connell@cira.colostate.edu Contributors: F. Prata (CSIRO), S. Watkin (Met Office)

2. Outline 1) Background: detection of volcanic ash for aviation hazards 2) Background: detection of volcanic ash & SO2 for human health hazards 3) Techniques for ash detection 4) Examples 5) Limitations 6) Selected References

3. 1. Background: Detection of Volcanic Ash for Aviation Hazards Eruption of Grimsvötn, 2 Nov 2004

4. Motivation “Ash clouds are not an everyday issue and they do not provide frequent hazard. But if encountered, volcanic ash can spoil your entire day.” (Engen, 1994)

5. Motivation • Between 1975 and 1994, more than 80 jet airplanes were damaged due to unplanned encounters with drifting clouds of volcanic ash. • Seven of these encounters caused in-flight loss of jet engine power, .. Putting at severe risk more than 1,500 passengers. • The repair and replacement costs associated with with airplane-ash cloud encounters are high and have exceeded $200 million. (Casadevall, 1994)

6. This picture shows the blades from a jet turbine which ingested airborne volcanic ash. The ash was melted and formed a glassy coating on the blades, covering cooling passeges and destroying the engine's efficiency.

7. More Background • The primary cause of in-flight engine loss was the accumulation of melted and resolidified ash on interior engine vents which reduced the effective flow of air through the engine, causing it to stall. • Volcanic ash is abrasive, mildly corrosive, and conductive. Airframes and engine components can be destroyed. Windshields are especially vulnerable to abrasion and crazing.

8. Global volcano distribution. Open triangles represent volcanoes believed to have erupted within the last 10,000 years, and filled triangles indicate those that have erupted within the 20th century. (Simkin, 1994)

9. Important Aviation Considerations • The height that columns can reach and then disperse their load of ash into the prevailing winds. • The column rise rate. • The content of fine ash that may be suspended or falling in the atmosphere for considerable distances or periods. • The duration of the ash clouds.

10. Importance of Remote Sensing • Global coverage • Allows for tracking of the plume both during the day and at night. • Provides information in remote locations • Can be used in conjunction with soundings to determine plume height and probable plume movement.

11. Three parts or regions of an eruption column: gas thrust, convective thrust, and umbrella. (Self and Walker, 1994)

12. Three possible modes of behavior of eruption columns - intensity of eruption increases from left to right. Wind is from the left in each case. At side of each diagram are shown normalized velocity (v) profiles versus height (h) for these columns. Left, weak isolated thermals, which are influenced by the wind. Center, a higher intensity buoyant column, influenced by wind only at the top. Right, a high intensity, superbuoyant column with a pronounced umbrella region. (Self and Walker, 1994)

13. 2. Background: Detection of Volcanic Ash and SO2 for Human Health Hazards Mt. Etna Eruption in October 2002

14. Volcanic Ash: Effects on Human Health • Respiratory symptons: potential respiratory symptoms from the inhalation of volcanic ash. • Eye symptons: because volcanic ash is abrasive, people typically experience eye discomfort or irritation during and after ash fall, especially among those that use contact lenses. • Skin irritation: minor skin irritations are sometimes reported following ashfall. • Mechanical effects: roof collapses and automobile accidents. The weight of volcanic ash on roofs can lead to their collapse, especially if the ash is wet and the building is not designed to support a heavy load. from: U.S. Geological Survey

15. Volcanic Ash: Effects on Human Health Principal health effects caused by ash fall from selected historical eruptions from: U.S. Geological Survey

16. SO2: Effects on Human Health • Stomach illnesses • Respiratory and bone diseases • Fluoride overdoses cause a variety of sickness and turning people's teeth transparent Other Effects • SO2 produces acid precipitation • Destruction of land by volcanic fallout

17. 3. Techniques for Ash Detection Eruption of Grimsvötn, 2 Nov 2004

18. Techniques for Ash Detection Use of single-channel imagery: • HRV (channel 12) • IR3.9 (reflected component) Use of multi-channel imagery: • 12.0 m – 10.8 m brightness temperature difference (BTD) • 3.9 m - 10.8 m BTD • 10.8 m - 8.7 m BTD • 13.4 m - 7.3 m BTD • 3.9 / 8.7 / /10.7 / 12.0 / 13.4 m combined product RECALL: emissivity + reflectivity + transmissivity = 1

19. HRV • Difficulty to detect thin ash clouds • Detection depends on reflectivity of underlying surface (detection easier over dark ocean) • Detection depends on satellite and sun angles (detection easier in the early morning hours) • Animation helps!

20. HRV: Example Met-8, 2 September 2005, 06:00 UTC, Mt. Etna, Sicily Click on the icon to see the animation(05:30-07:15 UTC, MPG, 1533 KB) !

21. IR12.0 - IR10.8 BTD • Volcanic ash clouds with a high concentration of silicate particles exhibit optical properties in the infrared (8-13 m) that can be used to discriminate them from normal water/ice clouds. • Emissivity of silicate particles is lower at 10.8 m than at 12.0 m • Emissivity of water/ice particles is higher at 10.8 m than at 12.0 m ==> IR12.0 - IR10.8 BTD tends to be positive for ash clouds with a high concentration of silicate particles (also for dust storms and desert surfaces) ! Remember: This BTD also depends on height of the cloud/humidity content.

22. IR12.0 - IR10.8 BTD Focus on zenith angles < 50 degrees: For quartz: IR11.8 - IR10.9 = positive For volcanic dust: IR11.8 - IR10.9 =~no difference For ice and water IR11.8 - IR10.9 = negative Satellite simulated brightness temperatures as a function of zenith angle for quartz and volcanic dust clouds (left) and water and ice clouds (right) at 10.9 m and 11.8 m (Prata and Barton, 1994)

23. IR12.0 - IR10.8 BTD: Example positive differences negative differences IR10.7 Difference IR12.0 - IR10.7 GOES-8, 20 July 2000, 16:39 UTC, Lascar, Chile

24. IR12.0 - IR10.8 BTD: Scatterplot

25. IR3.9 - IR10.8 BTD • The 3.9 um channel has both a strong reflected component during the day, as well as an emitted terrestrial component. • At night, there is no reflected component – only the emitted (and transmitted) components.

26. IR3.9 - IR10.8 BTD: Day-Time Examples MSG-1, 2 Nov 2004, 14:00 UTC Eruption of Grimsvötn Range: 0 K (black) to +50 K (white) MSG-1, 25 Jun 2003, 10:00 UTC Dust storms Middle East Range: -5 K (black) to +45 K (white)

27. IR10.8 - IR8.7 BTD • Volcanic plumes with a high concentration of sulfur dioxide (SO2) can be detected in the IR10.8 - IR8.7 BTD image (because of SO2 absorption band at IR8.7) • SO2 clouds are more transparent at IR10.8 than at IR8.7 (i.e. positive IR10.8 - IR8.7 BTD) • Ice clouds are more transparent at IR8.7 than at IR10.8(i.e. negative IR10.8 - IR8.7 BTD) • IR10.8 - IR8.7 BTD for SO2 clouds depends on lapse rate and can be negative in case of temperature inversions

28. IR13.4 - WV7.3 BTD • Volcanic plumes with a high concentration of sulfur dioxide (SO2) can also be detected in the IR13.4 - WV7.3 BTD image (because of SO2 absorption band at IR13.4) • However, IR13.4 - WV7.3 BTD is strongly influenced by surface temperature variations and by changes in the water vapour content so that the signal from the SO2 plume is only visible at certain times (e.g. at night in the case of the Nyiragongo eruption in July 2004) • Also, IR13.4 - WV7.3 not sensitive to low-level SO2 clouds

29. Transmittance of SO2 Clouds (From CIMSS, University of Wisconsin and CSIRO, Melbourne)

30. Nyiragongo IR10.8 - IR8.7 IR10.8 IR10.8 - IR8.7 BTD: Example MSG-1, 12 July 2004, 08:15 UTC Nyiragongo eruption, Dem. Republic of the Congo

31. Combined ProductsExperimental Volcanic Ash Product (Ellrod et al. 2001) B = C + m [T(12.0) - T(10.7)] + [T(3.9) - T(10.7)] with: B= output brightness value C=constant=60 (determined empirically) M=scaling factor=10 (determined empirically) T= brightness temperature at (wavelength) Experimental Ash Product Lascar, Chile, 20 July 2000, 16:39 UTC

33. Combined ProductsPossible RGB Composites • RGB VIS0.8, IR10.8-IR8.7, IR12.0-IR8.7 • (for SO2 clouds) • RGB IR12.0-IR10.8, IR10.8-IR8.7, IR10.8 • (similar to dust RGB, but different ranges) • RGB IR12.0-IR10.8, IR10.8-IR3.9, IR10.8 • (similar to fog RGB, but different ranges) • RGB IR12.0-IR10.8, IR3.9-IR10.8, IR10.8-IR8.7 • RGB HRV, HRV, IR10.8-IR12.0 • ...

34. 4. Examples Eruption of Pinatubo, June 1991

35. Volcanic Eruption, 10 May 2004 Mt. NyamuragiraDemocratic Republic of the Congo

36. MSG VIS Channels, 06:00 UTC Mt. Nyamuragira Channel 01 (VIS0.6) Channel 02 (VIS0.8)

37. MSG NIR Channels, 06:00 UTC Channel 03 (NIR1.6) Channel 04 (IR3.9)

38. MSG IR Channels, 06:00 UTC Channel 07 (IR8.7) Channel 09 (IR10.8)

39. MSG HRV Channel, 06:00 UTC Lake Victoria Rwanda SO2 plumefaintly visible Burundi

40. MSG Differences IR Channels, 06:00 UTC The SO2 plume is best visible in the IR10.8 - IR8.7 brightness temperature difference image. As can be seen in the animation, large parts of Rwanda and Burundi are covered by the SO2 cloud, which moves in a south-easterly direction Difference IR10.8 - IR8.7 Difference IR12.0 - IR8.7 Range: -3 K (black) to +8 K (white) Range: -3 K (black) to +8 K (white) Click on the icon to see the animation(00:00-12:00 UTC, AVI, 6451 KB) !

41. IR10.8 - IR8.7 Colour Enhancement

42. MSG IR10.8 - IR8.7 vs IR13.4 - IR7.3 Difference IR10.8 - IR8.7 Difference IR13.4 - WV7.3 Range: -3 K (black) to +8 K (white) Range: 0 K (black) to +22 K (white)

43. RGB VIS0.8, IR10.8-IR8.7, IR12.0-IR8.7

44. Volcanic Eruption, 12 July 2004 Mt. NyiragongoDemocratic Republic of the Congo

45. Channel 12 (HRV) Shows Time Evolution Mt. Nyiragongo Click on the iconto see the animation(06:00-12:00 UTC,AVI, 3085 KB) ! Lake Kivu MSG-1, 12 July 2004, 08:15 ITC, Channel 12 (HRV) The animation shows two plumes coming from two locations close to each other: a faint plume extending southwest of the volcano, a thick plume extending to the southeast and an arc of ash stretching over Lake Kivu between the two plumes.

46. MODIS gives horizontal details but does not show time evolution Terra MODIS, 12 July 2004, RGB Composite Info on time evolution is not contained in single images from polar-orbiting satellites.Thus, one could have thought that the thin plume was something like the remnantsof the plume from an earlier eruption.

47. MSG IR Channels, 08:15 UTC Channel 07 (IR8.7) Channel 09 (IR10.8) The thicker plume extending to the southeast can faintlybe detected in the infrared channels

48. MSG IR10.8 - IR8.7 vs IR13.4 - IR7.3 IR13.4 - WV7.3 difference is strongly influenced by surface temperature variations and by changes in the water vapour content so that the signal from the SO2 plume is only visible at certain times ! Difference IR10.8 - IR8.7 Difference IR13.4 - WV7.3 Range: -8 K (black) to +8 K (white) Range: -6 K (black) to +20 K (white) Click on the icon to see the animation(10-12 July, hourly, AVI, 6297 KB) ! Click on the icon to see the animation(10-12 July, hourly, AVI, 6375 KB) !

49. MSG Diff. IR12.0 - IR10.8, 08:15 UTC Click on the icon to see the animation (10-12 July, hourly,AVI, 6389 KB) ! No ash plume visible ! (ash at high altitudes normally has a distinctive positive IR12.0 - IR10.8 temperature difference of more than 2 K) • Conditions for seeing the ash plume ! • semi-transparent ash clouds • small ash particles • large temperature difference between ash cloud and underlying surface • low water content in ash cloud Difference IR12.0 - IR10.8 Range: -10 K (black) to +1 K (white)

50. Sulphur Plant Explosion, 25 June 2003 Al-Mishraq , Mossul, Northern Iraq -Biggest ever man-made sulphur dioxide plume - "Observing the fire from space was the only wayto find out how severe it actually was, because therewas no way to monitor the pollution from the ground" (Simon Carn, University of Maryland Baltimore County) Terra, MODIS, 25 June 2003, 10:35 UTC, RGB composite