PROGRESS REPORT: NASA SENH Grant NAG5-7576

November 18, 1998

"Application of TOMS Data to Volcanic Hazard Mitigation"

Principal Investigator: Gregg J.S. Bluth

Department of Geological Engineering and Sciences

Michigan Technological University

Houghton, MI 49931

Project Overview (from original proposal)

In this proposal I plan to analyze every eruption in the TOMS database from Nimbus, Meteor, ADEOS and Earth Probe instruments, using the latest (Version 7 and iterative) algorithms provided by our Collaborators in the Goddard TOMS SO2 group. For each eruption, we will calculate the total amount of emitted sulfur dioxide, and quantify the rate of SO2 removal by determining the rate of mass loss over time. Our volcanic hazards research will focus on the following objectives: (1) produce an internally consistent database of volcanic SO2 emissions over the lifetime of the TOMS instruments, available as both literary works and as publicly accessible documents on the TOMS SO2 Web Page; (2) investigate and document the fate of individual SO2 clouds as they decay in the atmosphere, for the purpose of developing models of chemical conversion; and (3) use the complete TOMS database to reassess and refine the annual sulfur loading of volcanoes in the atmosphere, for the purpose of documenting the volcanogenic contribution to atmospheric change and for predicting potential atmospheric and climatic impacts from volcanic eruptions.

Research Progress, 6/98 - 11/99

I was fortunate be located at Goddard this past summer (as a NASA Summer Faculty Research Fellow), to get a good start working with the TOMS SO2 group. The major issue at present is the inability of the present algorithm (version 7) to measure even mid-sized eruptions without saturating. This is a fundamental capability needed for this project, and I will continue to pressure the TOMS group to complete this. We made some progress during the past summer, but still there is no workable algorithm. We have been using version 6 of the algorithm when possible to make studies of SO2 decay. Otherwise, I am currently limited to study of smaller-scale eruptions.

I've made some good progress in documenting the small-scale eruptions to fill out the TOMS database. I have concentrating on eruptions by Nyamuragira (Zaire), a prolific volcanic which, for the past 15 years, erupts on the average of every 1-3 years. Due to political unrest, this volcano has been difficult for volcanologists to monitor and it appears that there is a great deal of "undetected" degassing which occurs. Each eruption lasted from a week to several months, typically emitting large amounts of TOMS-detectable SO2. For example, during the most recent (1996) eruption, I detected 15 days of activity, with a preliminary total of 650 ktons SO2. There are previous eruptions in 1980, 1981, 1984, 1986, 1987, 1988, 1989, and 1991 with only the 1981 eruption SO2 emissions documented in any detail (by Krueger et al., 1996, JGR, v. 101. 15,191-15,196). Thus, given these early results I expect a significant contribution of Nyamuragira to global annual SO2 loading.

My Ph.D. student, Sharon Barker, also was at Goddard this summer as a Summer Intern, and worked on identifying several mid-sized eruptions (200-5000 ktons SO2) in order to document and compare their rates of decay in the atmosphere. She found that the decay rate, or e-folding removal times, was strongly correlated to the size of emission. Some of her early results, to be presented at the Fall AGU meeting, are as follows: Mt. St. Helens 1980 (2 days e-folding), Alaid 1981 (8 days), El Chichon (11 days), Cerro Hudson 1991 (8 days), Spurr June 1992 (4 days), Spurr August 1992 (2 days), and Spurr September 1992 (2 days). Previous studies on El Chichon and Pinatubo estimated e-folding rates of approximately 35 days; this value has subsequently been used in modeling atmospheric SO2 removal rates. Thus, Sharon's work indicates that a major revision is necessary in order to accurately model volcanogenic SO2 loading to the atmosphere.

Research plans for upcoming period, 2/99

One of my main goals for the upcoming year is to produce a working algorithm out of version 7, in order to begin the task of systematically documenting and quantifying all of the TOMS-observable eruptions. I am working on more advanced methods of SO2 analysis, applying polygon-drawing techniques in order to more effectively isolate SO2 cloud masses from background. I expect that this will prove to be a large improvement in analyzing clouds, especially in regions with variable background conditions.

We will continue and expand our study of SO2 decay characteristics as much as possible to provide a range of conditions (e.g., emplacement altitude, original tonnage) and attempt to quantify the decay rates as a function of these characteristics. Given the "discovery" of Nyamuragira eruptions, I plan to concentrate on this volcano to quantify SO2 emissions over the past 2 decades, and link this abundant degassing to geochemistry/plumbing system.

Table 1. Publications and Presentations Related to SENH NAG5-7576

Publications

E.K. Constantine, G.J.S. Bluth, and W.I. Rose, (1998, in review) TOMS and AVHRR sensors applied to drifting volcanic clouds from the August 1991 eruptions of Cerro Hudson. Submitted to American Geophysical Union Special Monograph.

A.J. Krueger, S. Schaefer, N. Krotkov, G. Bluth, and S. Barker (1998, in review) Ultraviolet remote sensing of volcanic emissions and applications to aviation hazard mitigation. Submitted to American Geophysical Union Special Monograph.

N.A. Krotkov, O. Torres, C. Seftor, A.J. Krueger, W. Rose, A. Kostinski, G. Bluth, D. Schneider, and S.J. Schaefer. (1998, in review) Comparison of TOMS and AVHRR volcanic ash retrievals from the August 1992 eruption of Mt. Spurr. Submitted to Geophysical Research Letters.

Presentations

Barker, S.L., G.J.S. Bluth and A.J. Kreuger, Examining the removal rate of volcanogenic SO2 in the atmosphere. Fall 1998 AGU meeting, San Francisco, CA.

Bluth, G.J.S. and W.I. Rose, An interdisciplinary minor in remote sensing at Michigan Tech. Fall 1998 AGU meeting, San Francisco, CA.

Krueger, A.J., G.J.S. Bluth, and S.A. Schaefer, Contributions of Nimbus 7 TOMS data to volcanic study and hazard mitigations. Fall 1998 AGU meeting, San Francisco, CA.

Bluth, G.J.S., Volcanic Impacts on the Atmosphere, 1800-1997. Remote Sensing Colloquium Series, 11/2/98, Michigan Tech.

Barker, S.L., Examining the removal rate of volcanogenic SO2 in the atmosphere. Department of Geological Engineering and Sciences Seminar Series, 10/16/98, Michigan Tech.