PROGRESS REPORT: NASA SENH Grant NAG5-7576

December 20, 1999

"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, 12/98 - 12/99

Development of New Iterative Algorithm. Starting in late spring of 1999, a significant breakthrough in the TOMS SO2 processing algorithm finally made it possible for proper cloud analyses. This new algorithm uses radiative transfer and an iteration technique to produce a more realistic atmosheric model and thus a more accurate retrieval of volcanogenic SO2. This new algorithm still requires testing under eruption conditions, and I have been in regular contact with the Goddard SO2 group to keep them informed of our progress and vice-versa.

The iterative algorithm is so far working successfully, although the IDL-based processing software is no longer viable for data processing. My current work of eruption analyses is being done by spread sheet, which of course is slow but good enough for small eruptions. The main differences in the new algorithm is that it presents a more accurate mass retrieval without the overestimates of version 6, the underestimates of version 7, and without the 200 DU cutoff of version 7 algorithms. The problem of ash interaction remains however, and we are attacking this problem through a variety of methods. Concurrent experimental work (not supported by NASA SENH, but related) focuses on adsorption of SO2 on ash as a mechanism for SO2 removal (works by Gu et al., Table 2).

Data analysis. During the past year, I have purchased new research computer disk space, and have been systematically downloading TOMS data from the NASA archives for volcanic SO2 studies. I am advising a new Ph.D. student, Song Guo, who will be making significant contriibutions to this project. Song has an M.S. in Environmental Engineering from MTU, with specialties in atmospheric chemistry, particularly ozone. Song has entered the MTU program of Computer Sciences and Engineering, joint with the department of Geological Engineering and Sciences, and is working on the TOMS data processing algroithms and user interface.

Eruption analyses. The first eruptions I analyzed with the new algorithm were those in projects nearing completion. The Lascar eruptions of 1993 were first analyzed by one of my M.S. students, Heather Shocker (Shocker, 1996) - this work has expanded into a truly international collaboration, and I redid the SO2 and Aerosol Index analyses for this project (see Shocker et al., Table 1). In this work we observed physical separation of ash and gas components, an effect we have seen in other eruptions which may be due to sedimentation of ash particles. This separation has important implications for SO2 decay rates and of course atmospheric loading. Another M.S. student, Gari Mayberry, has been studying the 1997 Montserrat eruptions using TOMS among other satellite sensors, and likewise we reanalyzed the TOMS data. This work was included in her M.S. thesis (defended November 1999), and this work has been submitted for publication (Mayberry et al., Tables 1 and 2). In this eruption, the volcanic cloud was generated during a pyroclastic flow interacting with seawater. The interaction of the volcanic and meteorologic cloud led to the formation of a very "wet" volcanogenic cloud; the formation of ice appeared to aacavenge both ash and gas, providing yet another mechanism for sulfur removal. Most recently I analyzed the Shishaldin eruptions of 1999, which was a small event in the Aleutians. However, this was significant in its own right, as an example of an eruption detected solely by remote techniques. This eruption was therefore studied quite rigorously, and formed a strong contingent of poster presentations at the December 1999 AGU meeting in San Francisco.

Table 1. Manuscripts Related to This Project

Mayberry, G.C., W.I. Rose, and G.J.S. Bluth (1999, in review) Dynamics of the Volcanic and Meteorological Clouds Produced by the December 26, 1997 Eruption of Soufrière Hills volcano, Montserrat, W.I. Submitted to the Special Publicaion of the Geological Society of London, "The 1995-99 eruptions of Soufriere Hills volcano, Montserrat", edited by T. Druitt, S. Young and S. Blake.

Shocker, H.L., W.I. Rose, G.J.S. Bluth, A.J. Prata, and J.G. Viramonte (1999, in review) Lascar volcanic clouds of 1993: Merging of satellite-based remote sensing from TOMS, AVHRR, and ATSR during three days of atmospheric residence. Submitted to International Journal of Remote Sensing.

Constantine, E.K., G.J.S. Bluth, and W.I. Rose, (1999, in press) TOMS and AVHRR sensors applied to drifting volcanic clouds from the August 1991 eruptions of Cerro Hudson. American Geophysical Union Special Monograph.

Krueger, A.J., S. Schaefer, N. Krotkov, G. Bluth, and S. Barker (1999, in press) Ultraviolet remote sensing of volcanic emissions and applications to aviation hazard mitigation. American Geophysical Union Special Monograph.

Schneider, D.J., W.I. Rose, L.R. Coke, G.J.S. Bluth, I.E. Sprod and A.J. Krueger (1999) Early Evolution of a stratospheric volcanic eruption cloud as observed with TOMS and AVHRR, Journal of Geophysical Research, 104, 4037-4050.

Krotkov, N.A., O. Torres, C. Seftor, A.J. Krueger, W. Rose, A. Kostinski, G. Bluth, D. Schneider, and S.J. Schaefer (1999) Comparison of TOMS and AVHRR volcanic ash retrievals from the August 1992 eruption of Mt. Spurr. Geophysical Research Letters, 26, 455-458.

Table 2. Presentations Related to This Project

Gu, Y., J. Gierke, G. Bluth and W. Rose (1999) A laboratory study of SO2 adsorption on Mt. St. Helen's volcanic ashes. American Geophysical Union, December 1999.

Gu, Y., J. Gierke, and G. Bluth (1999) A laboratory study of SO2 adsorption on Mt. St. Helen's volcanic ashes. 22nd Midwest Environmental Chemistry Worshop, Michigan Tech, October 1999.

Bluth, G. and A. Krueger (1999) Volcanic SO2 emissions - a 20-year satellite record. IUGG Meeting, Birmingham, England, July 1999.

Mayberry, G.C., Rose, W.I., and G. Bluth (1999) Analysis of the evolution of the ash cloud from the December 26, 1997 (Boxing Day) dome collapse of Soufriere Hills Volcano, Montserrat, using GOES-8 imagery. IUGG Meeting, Birmingham, England, July 1999.

Research plans for upcoming year

With the success of the new iterative algorithm, I will continue on the systematic evaluation of TOMS database. Originally I had intended to focus on the larger eruptions, but the current limitations of the software processing abilities makes the method practical only for the smaller events. I will catalog each eruption with map of SO2, Aerosol Index, and a table of SO2 cloud retrieval characteristics. My intention is that this work would form the basis for a "TOMS volcano atlas", although that is beyond the scope of this project. However, I'd like to produce results and a reference source for satellite studies of global volcanism that will not need to be continually revised. Work on decay rates, begun last year, from larger eruptions will have to wait until the processing software is revised. Along those lines, Song Guo will work on revamping the TOMS SO2 processing software, starting with very simple imaging and mass retrievals, working into more complex image analysis tools.

Provided our work with the processing software progresses adequately, I plan to collaborate with Nick Krotkov (NASA/Goddard TOMS SO2 Group) on the June 1992 Mt. Spurr eruption using cloud altitude constraints provided by one of my past M.S. Students (Shannon, 1996), and comparing TOMS and AVHRR retrievals.

Dr. G. Bluth, Project PI Date