The Volcanic Ash Strategic‐Initiative Team

K. Stebel, F. Prata, E. Sollum, N. Kristiansen and A. Stohl (NILU)

G. de Leeuw, T. Virtanen, M. Sofiev and J. Vira (FMI)

G. Wotawa, D. Arnold and C. Maurer (ZAMG)

C. O'Dowd, D. Martin, J. Bialek and M. Hervo (NUIG)

C. Aas and M. Kamstra (S&T)

C. Zehner (ESA)

Volcanic ash

High silicate content Particle size (radius) ranges from 0.01–500 μm (typically) Irregular shape Melting point ~1100 ºC (800–1200 ºC).

Economics - EyaThe total impact on global GDP caused by the first week’s disruption amounts to approximately US$4.7 billion.

Flight tracks Jebel-at-Tairvolcanic cloud

vast.nilu.no

2 Steps:ash detectionash retrieval

Low clouduniformity over ocean, clouds at moderate to highZA,Cloud/SO2 test

//fred.nilu.no/sat/

Proactive ash detection monitoring

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Volcanic ash detection from AATSR

BTD=T11– T

12< 0

Etna, 10/28/2002 eruption.

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Aerosol models

Standard CCI aerosol models

model rg

(µm) σ m ALH (km)

non-absorbing fine 0.07 1.7 1.4 – 0.003i 0-2

absorbing fine 0.07 1.7 1.5 – 0.040i 0-2

sea salt 0.788 1.822 1.4 – 0.000i 0-1

dust 0.788 1.822 1.56 – 0.002i 2-4

model rg

(µm) σ m ALH (km)

TI01 0.142 1.7 1.47 - 0.0015i 0-2

TI10 1 1.7 1.47 - 0.0015i 0-2

TI20 2 1.7 1.47 - 0.0015i 0-2

Ash specific aerosol models (Andesite, Pollack 1973)

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Volcanic ash retrieval

AOD and mixing ratio are retrieved. From these we can derive the effective radius and column mass load.

Etna, 10/28/2002 eruption.

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Comparison to standard CCI retrieval

Here we compare the AODs retrieved with the ash specific model and with the standard CCI model

Etna, 10/28/2002 eruption. Left: ash specific retrieval. Right: standard CCI retrieval.

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Volcanic ash plume top height estimate

Due to parallax, the elevated ash plume is seen at different apparent position by nadir and forward views. An area based stereo matching

algorithm is used to produce an estimate of the plume top height.

Etna, 11/28/2002 eruption. Left) ash seen by nadir view (blue), forward view (green), or both views (red). Right) height estimate (km).

Grimsvótn volcano (64.25 N, 17.20 W, 1725 m)

SEVIRI ash retrieval 22-24 May 2011

AATSR AOD and plume height 22 May 2011

AIRS SO2 retrieval 24 May 2011

Modelling activities:

Satellite data assimilation SILAM (FMI)

Inverse modelling and source term determinationFLEXPART (NILU)

Ensemble modelling (ZAMG)

WRF-Chem(NUIG)

Emission inversion using OMI SO2 column

Grímsvötn time-height emission estimation,Unit: [kg SO2m

-1 sec-1].

Emission inversion using IASI SO2 column

Satellite data assimilation

3D-Eulerian dispersion model SILAM

0 24 48 72hr 0 24 48 72hr

20km 20km

Grimsvötn SO2 source

• Constrained with plume-top obs

• ~200 kton of SO2

• Unconstrained inversion

• 230 ktons of SO2

Both: OMI STL product, no a priori source, SILAM run at 0.5 deg resolution

OM

I

un

con

stra

ined

co

nst

rain

ed

22.05.2011 23.05.2011 24.05.2011

Agreement with OMI

FLEXPART Grimsvötn ash and SO2

- transported to different directions

Ash (IASI) SO2 (IASI*)

Was ash and SO2 emitted at different times and to different altitudes?

Moxnes et al. (2013), Separation of ash and sulfur dioxide during the 2011 Grímsvötn eruption

– source term estimates and transport modeling constrained by satellite observations, In Prep.* Courtersy L. Clarisse

Ash

Grimsvötn source terms for ash and SO2

SO2

Ash emitted to low altitudes

SO2 emitted to high altitudes

- determined from inverse modelling using IASI and SEVIRI satellite data

Moxnes et al. (2013), Separation of ash and sulfur dioxide during the 2011 Grímsvötn eruption

– source term estimates and transport modeling constrained by satellite observations, In Prep.

Hei

ght

of

emis

sio

n

Time of emission Time of emission

Emission strength (kg m-1 s-1)

Grimsvötn modelled dispersion of ash and SO2

Ash transported South-East

SO2 transported North-West

Moxnes et al. (2013), Separation of ash and sulfur dioxide during the 2011 Grímsvötn eruption

– source term estimates and transport modeling constrained by satellite observations, In Prep.

Ash (modelled) SO2 (modelled)

Modelled ash vs. ground-based PM10 measurements across Scandinavia

Moxnes et al. (2013), Separation of ash and sulfur dioxide during the 2011 Grímsvötn eruption

– source term estimates and transport modeling constrained by satellite observations, In Prep.

Black line=modelColuored bars=measurement

Demonstration operational testing of ash prediction services for global aviation

The demonstration operational tool is based in four different aspects providing results with different level of complexity to the end user (see poster by Wotawa et al. for details):

1. Trigger

2. Database and modelling tool

3. Ensemble modelling with the

ECMWF EPS system

4. Source term estimation with

(dynamic) inversion

1

Trigger:

1. Manual triggering2. Notification from SACS3. Ash detection from SEVIRI

Volcano database and modelling tool

- Web interface

- Database with basic information on

volcanos (release heights, durations,

percentage of fine ash folliwing

USGS/Mastin et al, 2009)

- GUI to set-up FLEXPART forecasts

- GUI to navigate through results

- Additional options for advanced results

(inversion, ensemble modelling, runs

with a given a posteriori source term)

2

3

Ensemble modelling using ECMWF EPS

1. Reduction of the number of ensemble members from 50 to5-6 with cluster analysis of key meteorological variables(Klonner, 2013).

2. FLEXPART runs with the full dataset for this 5-6 ensemblemembers to obtain a multi input mini ensemble.

4

Source term estimation

1. Ad-hoc inversion2. Dynamic inversion

(development) for extended events

Combination of the sensitivity fields obtained with the atmospheric transport model (updated with incoming meteorological data), satellite re-griddedretrievals and a priori information.

LIDAR network

4-node network in Ireland

Eye-safe UV LIDAR at Dublin Airport

(355 nm with a power of 12 mJ at 20 Hz)

LIDARS at Malin Head (North), Mace

Head (West) and Cork (South).

Real-time ash detection software

Temporal Height-Tracking approach

(Martucci et al., 2010, Milroy et al. 2011;

Haeffelin et al., 2011)

Data-streaming communications to both

the Irish Aviation Authority IAA and NUIG.

Volcanic AshConcentration Chart

http://macehead.nuigalway.ie/rt/lidars