Dispersion of oxidized sulfur from the Láscar Volcano in
connection with a subplinian eruption in April 1993 and noneruptive emissions in November 1989
A. Amigo (1,2) and L. Gallardo(1)
1. Center for Mathematical Modeling, University of Chile, Casilla 170, Correo 3, Santiago, CHILE
2. Department of Geology, University of Chile, Casilla 13518, Correo 21, Santiago, CHILE
Corresponding author: [email protected]
Introduction
The Andes are characterized by widely spread volcanism that
results in high emissions of sulfur compounds in connection
with both quiescent degassing and explosive events. Sulfur
emitted from volcanoes play an important role in the climatic
system, especially when eruptions can inject gases and
aerosol precursors into the upper troposphere and
stratosphere. However, these emissions are poorly
constrained. In this study, using a 3-D transport and chemistry
model, and analyzed meteorological fields, we assess the
dispersion and deposition of oxidized sulfur emitted from the
Láscar volcano (23.4ºS; 67.7ºW; 5592 m.a.s.l.) during a
subplinian eruption occurred on April 19-20 1993, and in
connection with fumarolic activity in November 1989.
SUBPLINIAN ERUPTION
APRIL 19-20 1993
% pulse
contribution
0.4 Tg SO2 were detected by TOMS
spectrometers aboard Nimbus-7 and Meteor-3
satellites for two days of eruption (Bluth et al.,
1997). The emissions occurred in pulses
according to (Gardeweg and Medina, 1994):
Observed
Emissions
ECMWF
The
SOx MIXING RATIO
TOTAL DEPOSITION
Modeling approach
Apr
20
Apr
19
FUMAROLES
NOVEMBER 1989
Reanalysis data
(winds, temperature, etc.)
0.5°horizontal resolution
43 levels
from 1000 up to 20 hPa
MODEL
Apr 25
MATCH
Andres et al. (1991) reported SO2 flux
measurements from high temperature
fumaroles of 2300 ± 1120 [MgSO2/day], i.e.
comparable to those days’ emissions from
a copper smelter in the area. Here we show
the evolution of the SOx plume and the
average relative contribution of both
sources:
+IC; +BC



c
  v.c  c.v - .( c' v' )  Q  S
t
SOx MIXING RATIOS
6.5 km
OH
May
05
S-SO2
S-SO4
6.0 km
Robertson et al, 1999
5.5 km
Conclusions
May
10
For the subplinian eruption of April 19-20 1993, the
overall pattern of SOx dispersion as seen in
satellite images is captured by the model. Also, the
simulated deposition is in accordance with
observations from ice cores at the Illimani and
Tapado glaciers.
TOMS:SO2
http://toms.umbc.edu
Although the strength of fumarolic emissions from
the Láscar volcano is comparable to the
anthropogenic one in the area, their impacts differ
substantially. Volcanic sulfur affects the upper •.
troposphere and to the east of the Andean range,
whereas anthropogenic sulfur affects the lower
troposphere to west of the Andean range.
NOAA-11: Ash
dispertion
References
http://www.volcano.si.edu
Ice cores
Fumarolic emissions v/s
Anthropogenic emissions, represented by
Chuquicamata copper smelter.
S
volc
Svolc+Sant
NEW PARTICLE FORMATION:
Preliminary results from an Aerosol
Box Model (Amigo et al, 2004)
Nucl
Aitken
•Amigo, A., Gallardo, L., Ekman, A., and Engardt, M, 2004. Andean volcanoes as
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et al, 2002
Illimani
The fumarolic emissions of SOx are mainly
transported to the east of the Andean range
following the westerly winds. This sulfur appears
to give rise to a significant production of new
particles that may play a role in cloud processes
occurring downwind from the volcano(es).
RELATIVE CONTRIBUTION:
HEIGHT [Km]
OBSERVATIONS
5.0 km
Tapado
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Acc
H2SO4
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Acknowledgements: We are grateful for the support provided by the staff at
the Swedish Meteorology and Hydrology Institute (SMHI), in particular Dr. M.
Engardt , and Dr. A. Ekman at Stockholm University. This work was partially
financed by the Center for Mathematical Modeling, University of Chile (CMM)
and FONDECYT Grant 1030809.