1. "Application of TOMS Data to Volcanic Hazard Mitigation"

2. Progress Report - December, 2000

3. Principal Investigator: Gregg J.S. Bluth

4. Period Covered: 12/99 - 12/00

5. Institution Address:

Department of Geological Engineering and Sciences

Michigan Technological University

Houghton, MI 49931

6. NASA SENH Grant NAG5-7576

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 (see Tables 1 and 2)

Algorithm/software testing

Work on the new ("iterative") algorithm continued, with more widespread testing and application of the algorithm to various eruptions in the TOMS database. We are still finding cases of extreme changes in SO2 retrievals among the old version 6 (pre-1996), version 7 (1995-1999) and iterative (1999-present) algorithms, which require further examination. Under most conditions, the differences among the three versions are no more than 20%.

A major advance has come from our software revision of the TOMS data plotting routines. We have developed a faster version of the plotting software, needed because of the more computationally-intensive iterative algorithm. We are currently revising the software to accommodate different methods of SO2 tonnage analyses (e.g., summing of individual pixels, gridded, and contouring methods), and adding the ability to extrapolate values, which is needed for cases where TOMS data scans are missing.

Eruption analyses

The Pinatubo eruption has been the focus of my advisee, Ph.D. candidate Song Guo. The pertinent portions of his research are to revise the TOMS analyses of Pinatubo, using the recent algorithm and software advances. This involves modeling portions of the clouds for which the original data were missing due to scan losses, which will greatly improve the estimates of the original SO2 emission and decay rates.

Nyamuragira volcano has erupted 11 times over the past twenty years, for periods of days to months. I have been studying the overall emissions from this extremely prolific volcano, and thus far estimate a total emission of around 8 Mt, with nearly 80 days of observed clouds.

The TOMS Aerosol Index has the ability to detect some ash clouds, adding another dimension to the TOMS studies. Recently, we have also discovered that it can observe sulfate clouds, and this has been documented for the 2000 eruptions of Hekla, as well as several eruptions of Nyamuragira.

With David Schneider of AVO, we have been using TOMS and AVHRR data to examine cases of ash and gas separation in clouds. As the mechanism(s) for this phenomena are not well known, this represents a new opportunity for satellite studies which can document ash and gas species.

Web dissemination

We have developed a "Volcanic Clouds" web site (http://www.geo.mtu.edu/volcanoes/vc_web/), which is running but not yet complete. The Volcanic Clouds Web Site describes the formation and composition of volcanic ash, gas and aerosol clouds, the remote sensing methods we (at Michigan Tech) use to study them, and ways that this information can be used for science and hazard mitigation. The Volcanic Clouds Web Site lets users progressively build upon knowledge about clouds and remote sensing techniques, but also lets them skip from link to link as needed. Links to background material and a glossary of terms are embedded within the text. The Volcanic Clouds Web Site contains tutorials for learning how to study volcanic clouds by remote sensing. The site provides the information needed to find pertinent data sets, learn the required data processing techniques, and see case studies which demonstrate these skills and applications for a variety of environmental conditions.

Table 1. Manuscripts Related to This Project, 12/99-12/00

Rose, W.I., G.J.S. Bluth, D.J. Schneider, G.G.J. Ernst, C.M. Riley, L.J. Henderson, and R.G. McGimsey (in review) Observations of 1992 Crater Peak/Spurr volcanic clouds in their first few days of atmospheric residence. Submitted to Journal of Geology, July 2000.

Mayberry, G.C., W..I. Rose, and G.J.S. Bluth (in press) Dynamics of the volcanic and meteorological clouds produced by the December 26, 1997 eruption of Soufriere Hills volcano, Montserrat, W.I. Submitted to Special Publication of the Geological Society of London, The 1995-99 eruptions of Soufriere Hills Volcano, Montserrat, edited by T. Druitt, S. Young and S. Blake.

Krueger, A.J., S. Schaefer, N. Krotkov, G. Bluth, and S. Barker (2000) Ultraviolet remote sensing of volcanic emissions and applications to aviation hazard mitigation. Geophysical Monograph Series 116, Remote Sensing of Active Volcanism, American Geophysical Union, 25-43.

Constantine, E.K., G.J.S. Bluth, and W.I. Rose (2000) TOMS and AVHRR observations of drifting volcanic clouds from the August 1991 eruptions of Cerro Hudson. Geophysical Monograph Series 116, Remote Sensing of Active Volcanism, American Geophysical Union, 45-64.

Rose, W.I., G.J.S. Bluth and G.G.J. Ernst (2000) Integrating retrievals of volcanic cloud characteristics from satellite remote sensors - a summary. Philosophical Transactions of Royal Society, Series A, v. 358, 1585-1606.

Table 2. Presentations Related to This Project, 12/99-12/00

Bluth, G.J.S., and C.M. Oppenheimer (2000) Twenty years of TOMS observations of sulfur emission from Nyamuragira Volcano, Zaire (invited). EOS Transactions AGU, v. 81, F1276.

Ernst, G.J., L.J. Henderson, W.I Rose, G.J.S. Bluth, C.M. Riley, D.J. Schneider, and R.G. McGimsey (2000) Observations of 1992 Crater Peak/Spurr volcanic clouds in the first few days of atmospheric residence. EOS Transactions AGU, v. 81, F1287.

Guo, S., W.I. Rose, G.J.S. Bluth, C. Textor, H-F. Graf (2000) ATHAM model simulation of the 15 June 1991 Pinatubo volcanic plume. EOS Transactions AGU, v. 81, F1288.

Riley, C.M., W.I. Rose, C. Textor, H-F. Graf, G.J.S. Bluth and R.G. McGimsey (2000) Modelling particle aggregation and microphysical processes in the August 1992 Spurr eruption plume using ATHAM. EOS Transactions AGU, v. 81, F1288.

Rose, W.I., G. Bluth, C. Riley, M. Watson, T. Yu, and G.G. Ernst (2000) Potential mitigation of volcanic cloud hazards using satellite data: a case study of the February 2000 Hekla event and an unexpected NASA DC8 encounter. EOS Transactions AGU, v. 81, F1277.

Schneider, D.J., W.I. Rose, and G.J.S. Bluth (2000) Satellite observations of the separation of volcanic ash and sulfur dioxide in the atmosphere. EOS Transactions AGU, v. 81, F1276.

Shannon, J.M., G.J.S. Bluth, and W.I. Rose (2000) 3-D reconstruction of the Mt. Spurr volcanic clouds using AVHRR, TOMS and wind trajectory data. EOS Transactions AGU, v. 81, F1313.

Presentations (no published abstract)

Bluth, G., The 1992 eruptions of Mt. Spurr, Alaska: new insights from improved remote sensing data. Remote Sensing Institute Seminar Series, March 28, 2000.

Bluth, G., TOMS applications and research status. 4th COMET Symposium and Workshop, Fairbanks, AK, May 17, 2000.

Bluth, G., VOLCAM proposed satellite system. 4th COMET Symposium and Workshop, Fairbanks, AK, May 17, 2000.

Research plans for upcoming year

We have several tasks planned for the final period of funding:

1) Complete Nyamuragira paper. The analyses are nearly completed and a manuscript will be prepared documenting the observed activity by TOMS over the past 20 years.

2) Complete Ash and gas separation paper. David Schneider will be visiting MTU in the Spring of this year and we plan to consolidate our satellite studies into a single effort documenting the major cases of separation observed by satellite sensors.

3) Begin sulfate studies. The first cases of sulfate detection by TOM, Hekla and Nyamuragira, will be documented and published, as this provides a new application of the TOMS for volcanic cloud studies.

4) Begin MODIS/TOMS studies. The February 2000 eruption of Hekla was observed by both TOMS and MODIS, and is the subject of a focused effort to cross-compare and validate the SO2 retrievals. We may also have an opportunity with the January-early February eruption of Nyamuragira, but the MODIS dataset may not be available for that time.

5) Compile TOMS database. This is the culmination of our work with the software and retrieval techniques, and incorporates our individual case studies over the past 3 years.

6) Continue volcanic clouds web site. Our methodology, data and results are a part of this work, and the web site represents an outstanding repository for the volcanological and hazards community.