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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). Outline.

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slide1

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)

slide2

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

slide3

1. Background: Detection of Volcanic Ash for Aviation Hazards

Eruption of Grimsvötn, 2 Nov 2004

slide4

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)

slide5

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)

slide6

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.

slide7

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.
slide8

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)

slide9

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.
slide10

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.
slide11

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

slide12

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)

slide13

2. Background: Detection of Volcanic Ash and SO2 for Human Health Hazards

Mt. Etna Eruption in October 2002

slide14

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

slide15

Volcanic Ash: Effects on Human Health

Principal health effects caused by ash fall from selected historical eruptions

from: U.S. Geological Survey

slide16

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
slide17

3. Techniques for Ash Detection

Eruption of Grimsvötn, 2 Nov 2004

slide18

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

slide19

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!
slide20

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) !

slide21

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.

slide22

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)

slide23

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

slide25

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.
slide26

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)

slide27

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
slide28

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
slide29

Transmittance of SO2 Clouds

(From CIMSS, University of Wisconsin and CSIRO, Melbourne)

slide30

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

slide31

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

slide33

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
  • ...
slide34

4. Examples

Eruption of Pinatubo, June 1991

slide35

Volcanic Eruption, 10 May 2004

Mt. NyamuragiraDemocratic Republic of the Congo

slide36

MSG VIS Channels, 06:00 UTC

Mt. Nyamuragira

Channel 01 (VIS0.6) Channel 02 (VIS0.8)

slide37

MSG NIR Channels, 06:00 UTC

Channel 03 (NIR1.6) Channel 04 (IR3.9)

slide38

MSG IR Channels, 06:00 UTC

Channel 07 (IR8.7) Channel 09 (IR10.8)

slide39

MSG HRV Channel, 06:00 UTC

Lake

Victoria

Rwanda

SO2 plumefaintly visible

Burundi

slide40

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) !

slide42

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)

slide44

Volcanic Eruption, 12 July 2004

Mt. NyiragongoDemocratic Republic of the Congo

slide45

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.

slide46

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.

slide47

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

slide48

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) !

slide49

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)

slide50

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

slide51

Sulphur Plant Explosion, Al-Mishraq:

Some Figures

  • The fire burned for almost a month
  • A total of around 600,000 tonnes of sulphur dioxide was released by the fire.
  • To put that figure in context, the giant eruption of Mount St Helens in 1980 belched out about one million tonnes of sulphur dioxide
  • The fire caused about $40m of damage to local crops - along with respiratory problems in local people
  • More than 40 percent of the trees lost their leaves in a radius of 100 km from the plant

(BBC News)

slide52

Channel 12 (HRV) Shows Time Evolution

Click on the iconto see the animation(02:00-08:00 UTC,AVI, 3454 KB) !

Sulphur

Plant

MSG-1, 25 June 2003, 10:00 ITC, Channel 12 (HRV)

slide53

MSG IR Channels, 10:00 UTC

Channel 07 (IR8.7) Channel 09 (IR10.8)

During day-time, the IR8.7 channel was up to 21 K colder than the IR10.8 channeldue to strong absorption by the SO2 cloud of the radiation from the very hot surface

slide54

MSG IR10.8 - IR8.7 vs IR13.4 - IR7.3

SO2 cloud was limited to the Planetary Boundary Layer (PBL) and thus not detectable by the WV7.3 channel, which has the peak of the weighting function in the layer from about 700 to 400 hPa (depending on the humidity content) !

Difference IR10.8 - IR8.7 Difference IR13.4 - WV7.3

Range: -5 K (black) to +20 K (white) Range: -5 K (black) to +22 K (white)

Click on the icon to see the animation(00:00-12:00 UTC, AVI, 4617 KB) !

slide55

RGB VIS0.6, IR10.8-IR8.7, IR12.0-IR8.7

Fire sulphur plant

Dust storms

slide56

SCIAMACHY, Monthly Averaged SO2 Concentration

most of the SO2 plume went in easterly direction, towards the Caspian Sea, indicating prevailing winds from the west during the week(s) that followed the accident !

Source: University of Bremen

slide57

Volcanic Eruption, 02 November 2004

Grimsvötn, Iceland

Eruption of Grimsvötn, 2 Nov 2004, Alexander H. Jarosch

slide58

Eruption of Grimsvötn: Some Facts

  • The eruption plume was first detected on 1 November by weather radar. It reached an altitude of 13 km.
  • On 2 November, there were eruptions pulsed resulting in a changing eruption column height from 8-9 km up to 13-14 km
  • On 3 November 2004, the ash plume reached Norway, Finland and Sweden causing the diversion of trans-Atlantic flights to the south of Iceland to avoid the ash cloud
  • The Dutch airline KLM had to cancel 59 flights, stranding hundreds of passengers at Amsterdam's Schiphol Airport
  • The eruption of Grimsvötn volcano ended on 6 November 2004
slide59

Significant

Weather

Chart

slide60

Shadow on lower-level clouds

At 09:30 UTC, with the sun shining at low elevation angle from the south-east, the volcanic cloud produces a distinct shadow on the lower- level clouds that surround the volcano

Channel 12 (HRV) Shows Time Evolution

Click on the iconto see the animation(08:45-14:00 UTC,AVI, 5625 KB) !

Grimsvötn

MSG-1, 2 November 2004, 09:30 UTC, Channel 12 (HRV)

slide61

Channel 12 (HRV) in Mercator Projection

MSG-1, 2 November 2004, 12:30 UTC, Channel 12 (HRV)

slide62

MSG IR10.8 Channel

09:30 UTC 14:00 UTC

Animation of the IR10.8 channel data confirms the pulsating character of the Grimsvötn eruption on 2 November 2004: between 12:00 and 13:30 UTC the top of the volcanic plume cooled down from about -20°C to -55°C (11:00-14:00, AVI, 6565 KB)

slide63

MSG IR10.8 - IR8.7 vs WV7.3 - IR13.4, 14:00 UTC

The existance of sulfur dioxide within the plume is confirmed by the WV7.3 - IR13.4 and the IR10.8 - IR8.7 brightness temperature difference images at 14:00 UTC that clearly show the volcanic plume !

Difference IR10.8 - IR8.7 Difference WV7.3 - IR13.4

Range: -5 K (black) to +5 K (white) Range: -10 K (black) to +10 K (white)

Click on the icon to see the animation(11:00-14:00 UTC, AVI, 6567 KB) !

Click on the icon to see the animation(11:00-14:00 UTC, AVI, 6565 KB) !

slide64

MSG IR3.9 - IR10.8 vs IR10.8 - IR12.0, 14:00 UTC

From the IR10.8 - IR12.0 difference images it is difficult to confirm the presense of ash within the volcanic plume. Probably, there was too much water vapour in the volcanic cloud and/or the ash particles were too big/heavy so that most of them dropped down in the vicinity of the volcano.

Difference IR3.9 - IR10.8 Difference IR10.8 - IR12.0

Range: 0 K (black) to +50 K (white) Range: -2 K (black) to +8 K (white)

Click on the icon to see the animation(11:00-14:00 UTC, AVI, 6565 KB) !

Click on the icon to see the animation(11:00-14:00 UTC, AVI, 6565 KB) !

slide65

5. Limitations

Eruption of Mount St. Helens, 8 March 2005

challenges to using the 10 8 12 0 um difference product
Challenges to using the 10.8-12.0 umdifference product
  • For optically thick plumes, when water and ice are mixed with the volcanic debris, the ‘ash’ signal may be confused
  • Low ash concentrations can be difficult to detect
challenges to using the 3 9 10 8 um difference product
Challenges to using the 3.9-10.8 umdifference product
  • Limitations to measurements for cold scenes at 3.9 um:
    • The steep slope of the Plank function at cold temperatures (<-50 C), the instrument noise at 3.9 um becomes very large
  • Uncertainties with properties of reflectance/emittance/transmittance of the ash cloud
other uses of satellite imagery for volcano monitoring
Other uses of satellite imagery for volcano monitoring
  • Hot spot detection (with IR3.9 channel)
  • Determination of cloud height with VISIBLE shadow technique (with HRV channel)
slide69

SUMMARYDetection of Volcanic Ash & SO2

  • HRV: to monitor time evolution during day-time (problem with very thin volcanic ash clouds)
  • IR12.0 - IR10.8 for detection of ash clouds with high silicate concentration (especially for thin, high-level ash clouds), discriminates well between ash and ice clouds
  • IR3.9 - IR10.8 also good (especially for thin, high-level ash clouds), but no discrimination between ash and thin ice clouds
  • IR10.8 - IR8.7 for detection of SO2 clouds
  • IR13.4 - WV7.3 less useful for detection of SO2 clouds
  • Combined Products using IR12.0-IR10.8, IR3.9-IR10.8 and IR10.8-IR8.7 !
slide70

6. Selected References

Prata, A. J. 1989: Observations of volcanic ash clouds in the 10-12 um window using AVHRR/2 data. Int. J. Remote Sensing, 10 (4 and 5), 751-761.

Engen; Cassadevall; Simkin; Self and Walker; Prata and Barton, Schneider and Rose, and other articles can be found in: Casadevall, T. J., 1994: Volcanic Ash and Aviation Safety: Proceedings of the First International Symposium on Volcanic Ash and Aviation Safety. U.S. Geological Survey Bulletin 2047.

Ellrod, G. P., B. H. Connell, and D. W. Hillger, 2001: Improved detection of airborne volcanic ash using multispectral infrared satellite data. J. Geophys. Res., 108 (D12), 6-1 to 6-13