The effects of volcanic ash on COSPEC measurements

Citation
Rj. Andres et Jw. Schmid, The effects of volcanic ash on COSPEC measurements, J VOLCANOL, 108(1-4), 2001, pp. 237-244
Citations number
17
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Earth Sciences
Journal title
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH
ISSN journal
0377-0273 → ACNP
Volume
108
Issue
1-4
Year of publication
2001
Pages
237 - 244
Database
ISI
SICI code
0377-0273(20010815)108:1-4<237:TEOVAO>2.0.ZU;2-P
Abstract
Data from a series of laboratory experiments show the relationships between measured correlation spectrometer (COSPEC) sulfur-dioxide (SO2) burdens, a utomatic gain control (AGC) deflections, and visible wavelength opacities i n ash-laden plumes. The data show that the COSPEC reliably measures (within a 10% accuracy) SO2 burdens up to AGC deflections of 2 V and visible wavel ength opacities of 50%. Beyond these Emits, the under measurement of the SO 2 burden is not well constrained. During typical COSPEC runs, these limits are rarely violated. The 10% error introduced by measuring ash-laden plumes is acceptable because the error is small relative to other error sources a ssociated with the technique, especially plume velocity; and the error is c orrectable which allows for a wider range of plume conditions to be measure d. These results imply that the densest SO2 concentrations near the volcanic s ource can be measured. This is important so that SO2 is not lost from the v olcanic plume due to physical and chemical processes and that measurements are conducted under maximum signal to noise ratios. (C) 2001 Elsevier Scien ce B.V. All rights reserved.