HR: 08:15h
AN: V21E-02    [Abstracts]
TI: Aerosol Measurements From Recent Alaskan Volcanic Eruptions: Implications for Volcanic Ash Transport Predictions
AU: * Cahill, C F
EM: ffcfc@uaf.edu
AF: Department of Chemistry and Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK 99775, United States
AU: Rinkleff, P G
EM: prinkleff@gi.alaska.edu
AF: Department of Geology and Geophysics and Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK 99775, United States
AU: Dehn, J
EM: jdehn@gi.alaska.edu
AF: Alaska Volcano Observatory, Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK 99775, United States
AU: Webley, P
EM: pwebley@gi.alaska.edu
AF: Arctic Region Supercomputing Center and Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK 99775, United States
AU: Cahill, T A
EM: tacahill@ucdavis.edu
AF: DELTA Group, Department of Chemical Engineering and Material Science, University of California, Davis, Davis, CA 95616, United States
AU: Barnes, D E
EM: debarnes@ucdavis.edu
AF: DELTA Group, Department of Chemical Engineering and Material Science, University of California, Davis, Davis, CA 95616, United States
AB: Size and time-resolved aerosol compositional measurements conducted during the 2006 Augustine Volcano and 2007 Pavlof Volcano eruptions provide ground-truth information for use in the validation of volcanic ash transport models. These measurements provide quantitative information on the size and concentration of the aerosol, which can be used to test the volcanic aerosol source profiles and transport characteristics used in volcanic ash transport models. Augustine Volcano is on an island in Cook Inlet in southern Alaska. For the 2006 Augustine Volcano eruption, the size and time-resolved aerosol measurements were made using an eight stage (35-5.0, 5.0-2.5, 2.5-1.15, 1.15- 0.75, 0.75-0.56, 0.56-0.34, 0.34-0.26 and 0.26-0.09 microns in aerodynamic diameter) DRUM aerosol impactor deployed in Homer, approximately 120 km northeast of the volcano. Aerosols from the volcano reached the sampler and showed that the size distribution of the volcanic emissions changed during the course of the eruption. For example, crustal elements were present in high concentrations in the largest size fraction (35-5.0 microns) but low concentrations in a smaller size fraction (0.75-0.56 microns) during the phreatomagmatic explosive events. However, during the magmatic emissions period, the concentrations of these elements in the large size fraction decreased, but greatly increased in the smaller size fraction. Pavlof Volcano is a volcano on the Alaska Peninsula in southwestern Alaska. During the 2007 Pavlof Volcano eruption, a network of four DRUM aerosol impactors was deployed downwind of the volcano in an attempt to characterize the change in aerosol size distribution and composition during transport away from the volcano. The samplers were located at Nelson Lagoon, approximately 80 km northeast of the volcano (eight stage DRUM impactor with a top cut point of approximately 12 microns), Sand Point approximately 90 km east of the volcano (three stage DRUM impactor with aerodynamic diameter size fractions of 2.5-1.15, 1.15-0.34 and 0.34-0.01 microns), Kodiak, approximately 550 km east-northeast of the volcano (three stage DRUM impactor), and Homer, approximately 680 km northeast (three stage DRUM impactor). The aerosol samples collected by the DRUM impactors were analyzed with 90 minute resolution for the entire duration of the six-week sample periods. The collected aerosol was analyzed for mass using a beta-gauge and elemental composition (28 selected elements between sodium and lead) using synchrotron x-ray fluorescence. The results from Pavlof Volcano will be compared to those of Augustine Volcano to determine the variability of aerosol emissions between the two eruptions. The Pavlof Volcano aerosol network will also be used to examine changes in size distribution and composition as the aerosols transport away from the volcano. The information gained from these analyses will be compared to volcanic ash transport model predictions to help quantify the limitations of the models and improve future volcanic ash predictions.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0370 Volcanic effects (8409)
DE: 0394 Instruments and techniques
DE: 8409 Atmospheric effects (0370)
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting