Atmospheric and Climate Sciences, 2011, 1, 48-54
doi: 10.4236/acs.2011.12005 Published Online April 2011 (http://www.SciRP.org/journal/acs)
Copyright © 2011 SciRes. ACS
Eyjafjallajökull Volcanic Eruption: Ice Nuclei and
Particle Characterization
Franco Belosi, Gianni Santachiara, Franco Prodi
Institute of Atmospheric Science and Climate (ISAC), National Research Council, Bologna, Italy
E-mail: g.santachiara@isac.cnr.it
Received March 8, 2011; revised March 21, 2011; accepted March 28, 2011
Abstract
The Eyjafjallajökull 2010 eruption was an extraordinary event in that it led to widespread and unprecedented
disruption to air travel over Europe – a region generally considered to be free from the hazards associated
with volcanic eruptions, excluding the extreme south influenced by Mt. Etna. In situ measurements were
performed at the research centre of the National Research Council (CNR) area of Bologna (44˚31 N; 11˚20
E), an urban background site, in order to contribute to knowledge concerning the impact of the volcanic
emission.Aerosol size distributions measured with a Differential Mobility Particle Sizer (DMPS) and an Op-
tical Particle Counter (OPC) show an increase in concentration of the accumulation and coarse fraction dur-
ing the transit of the ash cloud, with respect to the subsequent period of the event, while particles smaller
than 0.3 μm seem not to be affected by volcanic ash. Ice nuclei measured in the sampled air during and after
the ash cloud transit, show an higher concentration during the ash cloud transit, with a ratio of about 1:110
with respect to the aerosol number concentration measured with the OPC.The elemental composition of
aerosol particles, performed with SEM-EDX, gives about 30% of the inorganic coarse particles (geometric
diameter larger than 1 μm) of volcanic origin on the 20 April. Si and Al concentrations result prevalently
much higher than Ca and Fe ones. A large number of particles contained sulphur, indicating secondary proc-
esses of sulphate/sulphuric acid formation due to sulphur dioxide oxidation during transport in the volcanic
plume.
Keywords: Ice Nuclei, Nucleation, Supersaturation, Volcanic Ash
1. Introduction
Volcanic clouds are a suspension of particles similar to
meteorological clouds, generated by volcanic activity
and dispersed into the atmosphere. They include volcanic
ashes, hydrometeors (drops, ice crystals, hails), vapours
and gases. After the emission of ashes, gases and vapours,
there occur microphysical processes such as homogene-
ous or heterogeneous nucleation, hygroscopic growth,
coagulation, condensation, adsorption of species on to
the surfaces of other particles, chemical reactions
(gas-to-particles reactions and aqueous phase reactions),
as well as dry and wet deposition. As a consequence,
particle size distribution changes significantly with the
distance from the event. Droplets form as temperature
decreases during the rise, and sometimes freeze. The
release of latent heat during freezing affects plume buoy-
ancy and maximum plume height. Besides entrained
tropospheric water vapor, sources of water available for
volcanic cloud ice include magma, various hydrospheric
reservoirs (ocean, crater lakes, glaciers, groundwater)
and hydrothermal systems [1-3]. Ice in volcanic clouds
enhances ash fallout by forming composite aggregates
and may be dominant, subordinate or subequal to ash in
terms of mass in volcanic clouds. Rose et al., [4] reports
recent cases where ice was dominant (Rabaul, in Papua
New Guinea, 1994 eruption; Hekla, in Iceland, 2000
eruptions), cases where ice was clearly subordinate
(Augustine, in Alaska, 1986; Mount Spurr, in Alaska,
1992; Cleveland, in Alaska, 2001; Kluychevskoy, in
Kamchatka, 1994), and cases where there was a subequal
proportion of ice and ash in volcanic clouds (Pinatubo, in
Philippines 1991, El Chichón, in Mexico 1982). More
examples of ash dominant volcanic clouds are found at
all latitudes higher than 40˚, which suggests that tropo-
spheric water vapour which is much higher at tropical
F. BELOSI ET AL.
49
latitudes, influences volcanic cloud ice through the en-
trainment process [5].
Aerosol particles that catalyze the formation of ice
crystals in clouds are called Ice Nuclei (IN), and they can
form ice through homogeneous or heterogeneous proc-
esses. The homogeneous nucleation process involves
only pure water or solution droplets, and depends on the
mass and temperature of liquid water, or in aqueous so-
lution, on water activity [6]. Ice will not homogeneously
form from pure solution droplets, no matter how diluted,
at temperatures greater than about –38˚C [7].
Four heterogeneous nucleation mechanisms are dis-
tinguished for atmospheric ice formation: deposition
(direct transition from vapour to solid on a foreign parti-
cle below water saturation), condensation-freezing
(ice-phase forms as water vapour condenses on cloud
condensation nuclei at T < 0˚C and afterwards freezes),
contact-freezing and immersion-freezing. Heterogeneous
freezing occurs at lower ice-saturation ratios and a higher
temperature than homogeneous freezing.
The IN concentrations in the atmosphere constitute a
very small fraction of the aerosol population. Rosinski [8]
proposes an approximate ratio of 1:106, while Szyrmer
and Zawadzki [9] suggest that the concentration of IN in
a typical cloud (T= –10) is about seven to nine orders
of magnitude less than the total aerosol.
Concerning volcanic clouds, there are conflicting
views in the literature regarding the effectiveness of vol-
canic ash as IN, with some investigators concluding that
volcanic emissions contain abundant IN [10-12], while
others which suggest that at least some active volcanoes
do not release IN into the atmosphere [13-16].
Durant et al., [17] performed freezing experiments
with water drops containing volcanic ash. Silica-rich and
silica-poor particles were considered, with the authors
suggesting that fine ash-particles (defined as particles
with equivalent diameters between 1 and 1000 μm ) will
exhibit an onset of freezing between 250 - 260 K, finding
very little difference between the considered particles.
Such results imply that other physical properties such as
surface morphology, defects and active sites, play an
important role, implying that volcanic clouds are IN-rich
relative to meteorological clouds. It is important to high-
light that the modality of the experiment (particles put on
the surface or inside the volume of the distilled water
drops) means that only contact nucleation is considered.
In the case of the Eyjafjallajökull volcano (63˚38 N,
19˚36 W, summit 1666 m a.s.l.), the eruption started on
20 March 2010. The first phase was characterized by an
effusive eruption that produced lava flows on the ground
and only minor emissions into the atmosphere. Accord-
ing to Burton et al., [18], the SO2 and HF gas fluxes
produced by the eruption were about 3000 and 30 tonnes
per day, respectively, and the gas composition was very
rich in H2O (> 80% by mole; < 15% CO2 and < 3% SO2).
Sulphur dioxide is often used as tracer for volcanic
plumes [19].
On 14 April an explosive eruption of the volcano
started with the ash plume reaching a height of 9.5 km on
the first day, but later 5 - 7 km. There was frequent light-
ning (IES: Institute of Earth Sciences, University of Ice-
land, http://www.earthice.hi.is/).
The eruption started beneath a glacier, which intensi-
fied its explosiveness because water vapour was pro-
duced by the interaction of hot volcanic material with ice.
The explosive eruption continued with varying intensity
for over one month. A high pressure system in the south
of Iceland on 14/15 April and, later, in western Scandi-
navia, favoured the transport with north-westerly winds
of large amounts of erupted material, mostly volcanic ash,
water vapour and SO2, across the North-Eastern Atlantic
towards the British Isles, Scandinavia and, later on, to
Central Europe.
The aim of this study is to employ measurements of
aerosol size distribution, elemental composition and IN
concentration in air, to ascertain whether some of the
volcanic ash reached ground level.
2. Experimental
At the National Research Council (CNR) area of Bolo-
gna, an urban background site, was operating a sampling
station located on the roof (15 m above ground level) of
the Institute of Atmospheric Science and Climate (ISAC)
for instrument comparison purposes. The sampling sta-
tion was equipped with a DMPS system (DMA-L Model
5.500, Condensation Particle Counter Model 5.403,
Grimm GmbH) with aerosol size resolution between
0.010 and 1 m, and an OPC (Dust Monitor 1.108,
Grimm GmbH) with size resolution between 0.3 and 20
m. Aware of a possible transit of the volcano cloud
over Bologna, data were recorded from 19 April. Unfor-
tunately, a failure in the power supply stopped the meas-
urements during the afternoon, with recording resumed
the following day. Nevertheless, even if the data were
not continuosly collected, it was possible to observe dif-
ferences in the aerosol size distribution in the considered
period (20-22 April 2010).
Sampling of aerosol particles was performed on the
roof of ISAC simultaneously with the measurements of
the size distribution. Various aerosol fractions (PM1,
PM2.5, PM10) and total suspended particles (TSP)
were sampled on nitrocellulose membrane (Millipore
HABG04700, nominal porosity 0.45 m). Aerosol frac-
tions were sampled by inserting different sampling heads
(1 m, 2.5 m, and 10 m cut-point-Standard EN12341,
Copyright © 2011 SciRes. ACS
50 F. BELOSI ET AL.
TCR Tecora) in front of the filter. Meteorological data
(air temperature, wind speed, pressure) were also re-
corded.
Concentrations of IN were detected by the membrane
filter technique, using a replica of the Langer dynamic
developing chamber [20] housed inside a refrigerator.
Use of the dynamic chamber circumvents some of the
problems arising from the use of the static chamber, e.g.
that the moisture supply under static conditions may be
rather inadequate at a filter surface both in overcoming
the effect of hygroscopic particles and in activating all
potential ice nuclei.
For each sampling, PM1, PM2.5, PM10 and TSP fil-
ters were cut into four pieces, and one piece for each
fraction was inserted into the same metal plate, previ-
ously covered with a smooth surface of paraffin. The
four pieces of different filters (PM1, PM2.5, PM10 and
TSP) were exposed to water vapour for about half an
hour at constant supersaturation. This allowed the simul-
taneous development of PM1, PM2.5, PM10 and TSP ice
nuclei.
The supersaturations (Sice, Sw) are calculated theoreti-
cally from vapour pressures of ice and water at the con-
sidered temperatures [21]. Taking into account the accu-
racy of the air and sample temperature sensors, and of
temperature control systems, an experimental uncertainty
of about 6% for Sice and Sw was estimated. The details are
reported in Santachiara et al., [22]. Table 1 shows the
operating conditions.
The aerosol particles collected on TSP filter on 20
April were examined by Scanning Electron Microscopy
(SEM) coupled with an energy dispersive X-ray (EDX)
detector. One sector of TSP filter was mounted on an
aluminium holder using a carbon conductive adhesive
tape before the graphite coating. Semi-quantitative ele-
mental analyses of randomly selected particles were ob-
tained.
3. Results and Discussion
A high pressure system in the south of Iceland on 14/15
April and, later, western Scandinavia favoured the
transport by north-westerly winds of large amounts of
erupted material, mostly volcanic ash, water vapour, and
sulphur dioxide (SO2), across the North-Eastern Atlantic
towards the British Isles, Scandinavia and, later on, to
Table 1. Operating conditions of IN measurements.
Tair , ˚C Tfilter , ˚C Sice , % Sw , %
17 18 9.8 7.7
17 19 20.8 0.45
Central Europe [23].
The evidence of the arrival of the aerosol cloud over
Italy can be validated in various ways. Five-day backward
trajectories (http://ready.arl.noaa.gov/HYSPLIT.php) arriv-
ing in Bologna at medium (1000 m a.s.l.) and high level
(2000 m a.s.l.) on 20 April show air masses coming from
Iceland, while on 22 April the origin of the air masses is
completely different (Figure 1).
Since on 20 April the air masses came from Iceland at
1-2 km height and the boundary layer was around 1600
m (CALMET simulation, http://www.arpa.emr.it/sim), a
mixing with the surface was possible. Horizontal winds
at 850 hPa on 20 April 2010 came from the North-West
(a)
(b)
Figure1. Five day back trajectories on 20 April (a) and 22
April (b).
Copyright © 2011 SciRes. ACS
F. BELOSI ET AL.
51
sector, while on 22 April arrived from the West sector, as
can be inferred from BOLAM (BOlogna Limited Area
Model, www.meteoliguria.it/MAP/BOLAM).
The ash front was observed by lidar observations in
Florence from 19 April to 20 April (Institute of Applied
Physics, http://lidarmax.altervista.org/englidar/home.php).
Further evidence of the volcanic cloud travelling from
northern towards southern Italy on these days can be
inferred from an examination of the aerosol optical depth
(AOD) from the EARLINET observations [24], with a
peak at 12 am on 20 April and from AERONET Modena
station (44˚38 N,10˚56 E, http://aeronet.gsfc.nasa.gov/)
which shows in the same day an increase in the AOD at
440 nm wavelength (averaged value 0.419). In the fol-
lowing days (21 and 22 April) the AOD averaged values
are lower (0.390 and 0.330, respectively). It could be
excluded that this variation was due to local emissions,
as the daily PM10 averaged concentration values in the
urban area do not change in the sampling period.
Table 2 shows the two-hour averaged particle number
concentration in different size fractions calculated from
the samplings taken simultaneously with the ice nuclei
measurements (averaging time from 1 pm to 3 pm). The
aerosol fine fraction was obtained by means of DMPS
measurements, while accumulation and coarse fractions
were provided by OPC measurements.
It can be seen that measurements show an increase in
concentration of the accumulation and coarse fractions
(the latter very pronounced), on 20 April with respect to
22. On the other hand, the number concentration of par-
ticles in the fine fraction (diameter lower than 0.3 μm), a
little higher on the 22 compared with the 20 April, seems
to show that the abundance of particles smaller than 0.3
μm was not affected by volcanic ash.
The increase in large particles with the arrival of the
ash plum, followed by a subsequent decrease, and the
fact that the abundance of particles smaller than 0.3 μm
was not affected by volcanic ash, is shown also by
Flentje et al., [23] at the Global Atmosphere Watch
(GAW) Zugspitze/Hohenpeissenberg station (Germany).
Figure 2 shows the two averaged volume aerosol size
distributions obtained by the OPC on 20 and 22 April.
The data are averaged from 1 pm to 3 pm on both days.
The curves clearly show a mode in the coarse fraction on
the first day (20/04/2010), which becomes less evident
on 22 April.
Table 2. Averaged aerosol particle number concentration in
different size fractions (cm–3).
Period Fine fraction
0.01 - 0.3 m
Accumulati
on fraction
0.3 - 1 m
Coarse
fraction
> 1 m
20 April (1 pm - 3pm) 9797 77.4 1.3
22 April (1pm - 3 pm) 13552 40.4 0.3
Figure 2. Volume aerosol size distribution average from 1
pm to 3 pm on 20 and 22 April.
The fitting of the volume size distribution with a bi-
modal lognormal distribution function shows a first un-
resolved mode, for both days, at around 0.2 - 0.3 m
(volume median diameter), and a second mode with a
volume median diameter of 3 m (geometric standard
deviation of 2.5 and 3.1, on 20 April and 22 April, re-
spectively). Moreover, the fraction of particles in the
second mode is 68% on 20 April, and only 18% on 22
April. A similar size distribution is reported by Brunner
[25] at Junghfraujoch (3600 m). Therefore, also combin-
ing this with the backward trajectories analysis, it can be
confidently assumed that volcanic ash reached ground
level.
Table 3 and Table 4 show the measured concentra-
tions of IN, considering two values of Sice and Sw, in the
aerosol sampled on 20 and 22 April, sized according to
the aerodynamic diameter.
Measurements below water saturation (Sice = 9.8%; Sw
= –7.7%) should allow the detection of deposition (sorp-
tion) nuclei, while those above water saturation (Sice
=20.8%; Sw = 0.45%) indicate the detection also ofcon-
densation-freezing nuclei. It must be noted that IN con-
centrations point to different behaviours between the
aerosol sampled on 20 April and on 22 April, day on
which back trajectories and lidar observation show that
the influence of the volcanic emission should be negligi-
ble. As a matter of fact, while in conditions of subsatura-
tion with respect to water, the concentration are similar
for both 20 and 22 April samples, at supersaturation both
Table 3. Concentration of particles (m–3) active as IN in the
considered fractions (20 April 2010).
INPM1 INPM2.5 INPM10 INTSP
Sice = 9.8%; Sw = 7.7% 13 25 40 71
Sice =20.8%; Sw = 0.45% 461 539 462 704
Table 4. Concentration of particles (m3) ac tive as IN in the
considered fractions (22 April 2010).
INPM1 INPM2.5 INPM10 INTSP
Sice = 9.8%; Sw = 7.7%38 41 68 53
Sice=20.8%; Sw = 0.45%64 72 96 95
Copyright © 2011 SciRes. ACS
F. BELOSI ET AL.
Copyright © 2011 SciRes. ACS
52
with respect to ice (Sice = 20.8%) and water (Sw = 0.45%),
there is a marked increase of IN for the 20 April sample,
and only a moderate increase for the 22 April sample.
Previous measurements [22] performed in a rural area
(S. Pietro Capofiume, near Bologna, July 2007) gave a
lower INTSP concentration (110 m–3; Sice = 20% ; Sw =
2% ) than the value measured on 20 April (704 m–3),
although the supersaturation in this case is lower (Sice =
20.8% ; Sw = 0.45% ). At this supersaturation, the 20
April filter shows a ratio of IN (measured in the total
suspended particles) to aerosol number concentration
measured with optical counter (particle size larger than
0.3 μm), of about 1:110, while in the rural area of S.
Pietro Capofiume the mean value was 1:1700. For the 22
April filter, the same ratio is about 1:430.
The different behaviour of aerosol at low water super-
saturation should indicate some changes in the physical
and chemical properties of the particles. One of the rea-
sons of the marked increase in the IN concentration for
the 20 April sample at Sw > 0 could be the presence of
insoluble particles coated by soluble compounds, which
favour the growth of aerosol diameter and increase the
possibility of the freezing. As a matter of fact, larger
samples have a higher freezing temperature than smaller
ones, both in homogeneous and heterogeneous nuclea-
tion [26, 6].
In support of this statement, Brunner [25] measured an
increase of soluble compounds at Junghfraujoch (3600
m), i.e. , 4, 3
2
4
SO NH NO
, Ca2+, Mg2+, K+ during
Eyjafjallajökull eruption, with respect to values prior to
the event.
Using ground-based observations, Rolf et al., [27] de-
tected the ash cloud a few days after the April eruptions
with a lidar over Western Germany, Jülich (50˚54 N,
6˚24 E). Their measurements showed condensation of
ice on the ash particles and the growth of induced cirrus
clouds. Lidar measurements highlight areas with high
depolarization, which are indicative of ice particles.
As far as the elemental composition of aerosol parti-
cles is concerned, in order to try to distinguish ash parti-
cles from local crustal or anthropogenic sources, the
present study took into account the chemical analysis of
rocks from the Eyjafjallajökull 2010 eruptions (Institute
of Earth Sciences – University of Iceland). Inorganic
coarse particles on the filter were considered to be ash
particles in the presence of Si, Fe, Mg, Al, Ca, and in
addition K, or Ti, or S or Na, even in small concentra-
tions.
Figure 3 and Figure 4 show two particles and the
corresponding EDX spectrum, collected on 20 April,
which could be considered volcanic ash according to the
above mentioned criteria.
With these constraints, it was found here that 30% of the
inorganic coarse particles (geometric diameter larger
than 1 μm) could be considered to be volcanic origin on
20 April. The Si and Al concentrations were mostly
much higher than Ca and Fe ones. About 28% of the ash
particles examined and about 50% of the particles with
geometric diameter less than 1 μm contain sulphur,
probably indicating adsorption of S-rich particles onto
the coarse particles [28-30]. The small particles in vol-
canic ash plumes should be typically composed largely
of sulphuric acid.
4. Conclusions
Backward trajectories, lidar observations and aerosol
optical depth measurements performed by various re-
search centers, confirm that the ash cloud affected Italy
on 20 April.
Measurements of aerosol size distribution performed
with a DMPS and an OPC show an increase in concen-
trations of the accumulation and coarse fraction (the lat-
ter, very marked), on 20 April with respect to 22 April,
when, on the basis of five days back trajectories and lidar
observations, the influence of volcanic emission should
be negligible. On the other hand the number concentra-
tion of particles in the fine fraction (particle diameter less
Figure 3. SEM pictu re an d elemental analysis of a particle coll ected on 20 April.
F. BELOSI ET AL.
53
Figure 4. SEM picture and elemental analysis of a particle collected on 20 April.
than 0.3 μm), a little higher on 22 April than on 20 April,
seems to show that the abundance of particles smaller
than 0.3 μm was not affected by volcanic ash.
Measured concentrations of IN, considering two val-
ues of Sice and Sw, in aerosol sampled on 20 and 22 April,
evidence different behaviours of the sampled aerosol. In
fact, while in conditions of subsaturation with respect to
water, the concentration are similar for both the 20 and
22 April samples, at supersaturation with respect to both
ice (Sice = 20.8%) and water (Sw = 0.45%), there is a
marked increase of IN for the 20 April sample, and only
a moderate increase for the 22 April sample.
Previous measurements performed in a rural area
(S.Pietro Capofiume, near Bologna, July 2007) gave a
lower IN concentration (704 m3) than the value measured
on 20 April. The 20 April filter showed a ratio of INTSP
to aerosol number concentration measured with OPC of
about 1:110, while in the rural areas the mean value was
1:1700. For the 22 April filter, the ratio was about 1:430.
The different behaviour of aerosol at low water super-
saturation should indicate some changes in the physical
and chemical properties of the particles.
With regard to the elemental composition of aerosol
particles, using SEM-EDX observations, it was found
that 30 % of the inorganic coarse particles (geometric
diameter larger than 1 μm) could be considered to be of
volcanic origin on 20 April. Si and Al concentrations
were found to be prevalently much higher than the Ca
and Fe ones. About 28% of the ash particles examined
and about 50% of the particles with geometric diameter
lower than 1μm contained sulphur, probably indicating
the adsorption of S-rich particles onto the coarse parti-
cles. The small particles in volcanic ash plumes should
be typically composed largely of sulphuric acid.
5. Acknowledgements
We gratefully acknowledge the collaboration of Mr. F.
Corticelli (IMM-CNR) for SEM-EDX observations and
the Meteorological Service of the Regional Protection
Agency (ARPA-SIMC, Servizio Idro-Meteo-Clima, Bo-
logna). We thank Renato Santangelo and the staff for
establishing and maintaining the AERONET Modena
site used in this investigation.
6. References
[1] A. W. Woods, “Moist convection and the injection of
volcanic ash into the atmosphere,” Journal of Geophysi-
cal Research, Vol. 98, 1993, pp. 17627-17636.
[2] L. S. Glaze, S. M. Baloga, L. Wilson, “Transport of at-
mospheric water vapour by volcanic eruption col-
umns,”Journal of Geophysical Research, Vol. 102, 1997,
pp. 6099-6108.
[3] G. C. Mayberry, W. I. Rose, G. J. S. Bluth, “Dynamics of
the volcanic and meteorological clouds produced by the
December 26, 1997, eruption of Soufrière Hillsvolcano,
Montserrat,” W.I. In Druitt, T.; Young, S.; and Kokelaar,
P., eds. The 1995-99eruptions of Soufrière Hills Volcano,
Montserrat. Geological Society, London, Memoirs, Vol.
21, 2002, pp. 539-555.
[4] W. I. Rose, G. J. S. Bluth, I. M. Watson, “Ice in volcanic
clouds: When and Where?” Proceedings of the 2nd Inter-
national Conference on volcanic ash and aviation safety,
OFCM, Washington, DC, Session 3, 2004, pp. 27-33.
[5] L. S. Glaze, S. M. Baloga, L. Wilson, “ Transport of at-
mospheric water vapour by volcanic eruption columns,”
Journal of Geophysical Research, Vol. 102, 1997, pp.
6099-6108.
[6] T. Koop, B. Luo, A.Tsias, T. Peter, “Water activity as the
determinant for homogeneous ice nucleation in aqueous
solutions,” Nature, Vol. 406, 2000, pp. 611-614.
[7] H. R. Pruppacher, J. D. Klett, “Microphysics of Clouds
and Precipitation,” Kluwer Academic Publishers, Dord-
recht, 1997, pp. 954.
[8] J.Rosinski, “The role of natural and man-made ice-forming
nuclei in the atmosphere,”Advances in Colloid and Inter-
face Science, Vol.10, 1979, pp. 315-367.
[9] W.Szyrmer, I.Zawadzki, “Biogenic and anthropogenic
sources of ice-forming nuclei: a review,”Bulletin of the
Copyright © 2011 SciRes. ACS
54 F. BELOSI ET AL.
American Meteorological Society, Vol. 78,1997, pp.
209-228.
[10] K. Isono, K. Komabayasi, A. Ono, “Volcanoes as a
source of atmospheric ice nuclei,” Nature, Vol. 183, 1959,
pp. 317-318.
[11] P.V.Hobbs, C. M. Fullerton, G. C. Bluhm, “Ice nucleus
storms in Hawaii,” Nature, Vol. 230, 1971, pp. 90-91.
[12] T. Tanaka, “Ice nucleating activity and the mode of ac-
tion of volcanic ash ejected from Mt.Usu in Hokkaido.
-An improved method to remove hygroscopic materials
collected on a membrane filter,” Papers in Meteorology
and Geophysics, Vol. 31, 1980, pp.153-171.
[13] S. Price, J C. Pales, “Ice nucleus counts and variation at
3.4 km and near sea level in Hawaii,” Monthly Weather
Review, Vol. 92, 1964, pp. 207-221.
[14] R.F. Pueschel, B. G. Mendonca, “Dispersion into the
higher atmosphere of effluent during an eruption of Kila-
uea volcano,” Journal de Récherches atmosphériques,
1972, Vol. 6, pp. 439-446.
[15] R. C. Schnell, A. C. Delany, “Airborne ice nuclei near an
active volcano,” Nature, Vol. 264, 1976, pp. 535-536.
[16] R. C. Schnell, R. F. Pueschel, D. L. Wellman, “Ice nu-
cleus characteristics of Mount St.Helens effluents,”
Journal of Geophysical Research, Vol. 87, No.C13, 1982,
pp. 11109-11112.
[17] A. J. Durant, R. A. Shaw, W. I. Rose, Y. Mi, G. G. J.
Ernst, “Ice nucleation and overseeding of ice in volcanic
clouds,” Journal of Geophysical Research, Vol. 113,
No.D09206, 2008. doi: 10.1029/2007JD009064, 2008
[18] M. Burton, G. Salerno, A. La Spina, A., A. Stefansson, H.
S. Kaasalainen., “Gas composition and flux report. Insti-
tute of Earth Sciences: Eruption in Eyjafjallajökull 20
March to present,” available at:
http://www.earthice.hi.is/page/ies EYJO compiled, 2010.
[19] S. A.Carn, A. J. Krueger, N. A. Krotkov, K.Yang, K.
Evans, “Tracking volcanic sulfur dioxide clouds for avia-
tion hazard mitigation”, Natural Hazards, Vol. 51, 2009,
pp.325-343, doi:10.1007/s11069-008-9228-4, 2009.
[20] G. Langer, J. Rodgers, “An experimental study of ice
nuclei on membrane filters and other substrata,” Journal
of Applied Meteorology, Vol.14, 1975, pp. 560-571.
[21] C. Gueymard, “Assessment of the accuracy and comput-
ing speed of simplified saturation vapour equations using
a new reference dataset,” Journal of Applied Meteorology,
Vol. 32, 1993, pp. 1294-1300.
[22] G. Santachiara, L. Di Matteo, F. Prodi, F. Belosi, “At-
mospheric particles acting as Ice Forming Nuclei in dif-
ferent size ranges,” Atmospheric Research, Vol. 96, 2010,
pp. 266-272.
[23] H. Flentje, H. Claude, T. Elste, S. Gilge, U. Köhler, C.
Plass-Dülmer, W. Steinbrecht, W. Thomas, A. Werner,
W. Fricke, “The Eyjafjallajökull eruption in April 2010 –
detection of volcanic plume using in-situ measurements,
ozone sondes and lidar-ceilometer profiles,” Atmospheric
Chemistry and Physics, Vol. 10, 2010, pp.10085-10092.
[24] G. Pappalardo, I. Mattis, and the EARLINET team,
“Dispersion and evolution of the Eyjafjallajokull ash
plume over Europe: vertically resolved measurements
with the European LIDAR network EARLINET
ESA/EUMETSAT,”ESA/EUMETSAT Workshop on Vol-
canic Ash Monitoring, ESRIN, Frascati, Italy, May 26-27,
2010.
[25] D. Brunner, “In-situ, lidar, sonde and aircraft observa-
tions of volcanic ash in Switzerland,” ESA/EUMETSAT
Workshop on Volcanic Ash Monitoring, ESRIN, Frascati,
Italy, May 26-27, 2010.
[26] F. Prodi, G. Santachiara, V. Prodi, “A study of the effect
of size on ice nucleation in the aerodynamic range of par-
ticles,” Journal of Applied Meteorology, Vol. 21, 1982,
pp. 945-952.
[27] C. Rolf, M. Krämer, C. Schiller, “Ground based LIDAR
observations of the Eyjafjalla ash cloud over Jülich,
Germany,” International Aerosol Conference, Helsinki,
2010.
[28] W. I. Rose, “Scavenging of volcanic aerosol by ash: at-
mospheric and volcanologic implications,” Geology, Vol.
5, 1977, pp. 621-624.
[29] W. I. Rose, R. L. Chuan, R. D. Cadle, D. C. Wods,
“Small particles in volcanic eruption clouds,”American
Journal of Science, Vol. 280, 1980, pp. 671-696.
[30] C. S. Witham, C. Oppenheimer, C. J. Horwell,
“Volcanic ash-leachates: a review and recommend-
dations for sampling methods,” Journal of Volca-
nology and Geothermal Research, Vol. 141, 2005,
pp. 299-326.
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