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| Titel |
BrO formation in the plume of Pacaya volcano, high resolution plume chemistry at early plume ages |
| VerfasserIn |
Leif Vogel, Nicole Bobrowski, Victoria Cáceres Espinoza, Christoph Kern, Holger Sihler, Ulrich Platt |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250053960
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| Zusammenfassung |
| During February 2010 we carried out gas emission studies of the plume of Pacaya volcano
(Guatemala). The subduction zone volcano Pacaya which is characterized by basaltic to
basaltic andesitic lava is located 20 km south of Guatemala City. Recent unrest from this
volcano consisted of several events in the last decades in form of lava flows and strombolian
explosions as well as larger explosive eruptions. Recent major events occurred in 1998 and
May 2010 with debris and ash ejected up to 5000m and subsequent ash fall on
nearby cities, including the capital Guatemala City and its international airport La
Aurora.
Measurements were performed with two stationary ground based Multi-Axis Differential
Optical Absorption Spectroscopy (MaxDOAS) systems and a zenith looking DOAS system
mounted on a car. The car traverses were conducted downwind to the east of the volcano and
determined a total sulphur dioxide (SO2) flux of about 125tons/day. The MaxDOAS
instruments were placed side by side on the north-north-eastern flank of Pacaya
at a distance of 1km from the crater. We investigated volcanic emissions at early
plume ages (< 5 min) in vertical as well as horizontal direction, mapping ongoing
bromine chemistry at high temporal resolution. We report the first detection of
Bromine monoxide (BrO) at Pacaya volcano and the hitherto first capture of volcanic
BrO chemistry at high resolution at very early plume ages. An expected increase
of BrO/SO2 ratio from below the detection limit of 2.5 -
10-5 to 1.5 -
10-4 was
observed.
Alerted by some inconsistencies in a first order evaluation of the BrO concentrations, we
discovered a noticeable formaldehyde (HCHO) abundance in the lower atmosphere
around Pacaya. Although not of volcanic origin, it highlights possible artifacts and
pitfalls of previous spectroscopic measurements of BrO in the lower troposphere due
to cross correlations between the absorption cross sections of BrO and HCHO. |
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