Ozone Monitoring Instrument (OMI) - Total Ozone Mapping Spectrometer (TOMS)
Top Stories

Recent volcanic eruption data
OMI was launched on the EOS-Aura satellite in July 2004 and superseded Earth Probe (EP) TOMS in 2006. OMI SO2 data have not yet been officially released to the public, though we are currently evaluating preliminary, unvalidated OMI SO2 data and welcome enquiries. OMI is a hyperspectral UV-Visible spectrometer with 8-fold better ground resolution (13x24 km at nadir) and an order of magnitude higher sensitivity to SO2 than TOMS. Hence, OMI can detect passive volcanic degassing in addition to the eruptive emissions measured in the past by TOMS. OMI can also measure anthropogenic SO2 emissions. Some examples of early data from OMI can be seen on the NASA Earth Observatory website (see links above under Top Stories). The OMI instrument is a Dutch-Finnish Instrument, provided to the EOS/Aura mission by The Netherlands and Finland. NIVR (the Dutch space agency) is the overall program manager, in coordination with FMI (the Finnish Meteorological Institute). The Royal Netherlands Meteorological Institute (KNMI) is the Principal Investigator institute.

Below we present data for the most recent large eruption observed by the EP TOMS satellite. For a full listing of eruptions detected by the TOMS instruments since 1978, check our TOMS archive. We are occasionally adding Atmospheric Infrared Sounder (AIRS) volcanic cloud images to an AIRS archive. AIRS is a hyperspectral infrared (IR) spectrometer on the EOS-Aqua satellite, which has a daytime overpass ~10 minutes prior to EOS-Aura. The IR AIRS data (available since late 2002) permit interesting comparisons with the UV OMI and TOMS images.

Sierra Negra, Galapagos Islands: October 23, 2005

Sulfur Dioxide (SO2)

SO2 from Sierra Negra

More SO2

SO2 from Sierra Negra
Estimated SO2 mass on Oct 24: 0.5 Tg or 500 kilotons
See the archive for further details.
Other recent emissions: Anatahan (Marianas), Manam (PNG), Asama (Japan), Ambrym (Vanuatu)

Volcano Data Products

Sulfur Dioxide (SO2)

SO2 from Pinatubo

Ash and Aerosols

Ash from Pinatubo

These images are from the June 15, 1991 eruption of Mt. Pinatubo, Philippines. The gas and ash clouds were tracked by TOMS for several weeks as they encircled the Earth. These satellite observations demonstrate the enormous amounts of gas and ash emitted, as well as details such as differences in peak concentrations and geographic extent. TOMS also detects many smaller volcanic clouds - see the archive for a full list of eruptions detected to date.

Volcanic SO2 Loading

SO2-time plot

Recent chart of TOMS volcanic SO2 against time

This website documents the efforts of the TOMS Volcanic Emissions Group, based in the Joint Center for Earth Systems Technology at the University of Maryland Baltimore County (UMBC) and NASA Goddard Space Flight Center, to detect, track and measure volcanic eruption plumes from space. We also collaborate with researchers and students in the Volcanic Clouds study group at Michigan Technological University. Our group primarily uses UV satellite data from the Ozone Monitoring Instrument (OMI) on NASA's EOS-Aura satellite and the Total Ozone Mapping Spectrometer (TOMS) to map and quantify sulfur dioxide gas (SO2) emitted by volcanoes. We also use the TOMS instruments to map volcanic ash and aerosol emissions, using an "aerosol index". The aerosol index locates absorbing and non-absorbing aerosol clouds, which include volcanic ash clouds, sulfate aerosol, dust, and smoke clouds; however, at present it cannot discriminate among the absorbing species. For more information about TOMS aerosol retrievals (and ozone and other non-volcanic products such as UVB), as well as a description of each of the TOMS missions, see the TOMS project web page.