1. Incorporating OMI Data into USGS Volcano Monitoring
Anatahan Volcano, Mariana islands
Incorporating OMI Data into USGS Volcano Monitoring
Background on USGS Operations
Recent Alaska Example
Relation to Ground Measurements
M. Guffanti, D. Schneider, J. Ewert, T. Murray

2. US Volcanoes and Volcano Observatories
VHP
USGS has 5 partnered Volcano Observatories to monitor volcanic unrest and eruptions using a combination of ground, airborne, and remote-sensing techniques

3. Major Remote-Sensing Focus at the Alaska Volcano Observatory: at USGS in Anchorage and Univ. of Alaska Fairbanks-Geophysical Institute
Eruptions Affecting North Pacific Air Routes During the 1990’s

4. NON-US VOLCANO RESPONSES:
USAID-USGS Volcano Disaster Assistance Program (VDAP)
Mount St. Helens &
N.Sulawesi volcanoes (Indonesia)

5. KNMI Ozone Monitoring Instrument on NASA Aura Satellite
USGS is partner on multi-agency project funded by NASA and led by Univ. of Maryland to provide Near-Real-Time Volcanic Cloud Data for USGS, NOAA, and FAA Users.

6. Operational Use of OMI Volcanic SO2 Products
Operational Concept Under Development by NOAA, NASA, and U-MD:
NOAA/NESDIS runs orbital extraction and level 3 mapping routines to create digital data files and images that meet user requirements. NOAA/NESDIS will disseminate products to the users via established communications channels.
Public web site similar to the TOMS SO2 site to be set up. Clickable world map to bring up a list of files containing recent mapped SO2 data and images for pre-defined regions of the globe.
NOAA/NESDIS (Washington VAAC) will retain an intermediate term collection of near-real-time volcanic ash image products on line as well as on DVD; orbital volcanic ash data products for retrospective studies will be archived at NASA/Goddard.
Near-real-time products of interest (within 3 hours of overpass time)
Level 2 (orbital) segments containing volcanic SO2 or volcanic ash signatures with geolocation and other auxiliary information appended; spacecraft projection in HDF5 format with appropriate metadata
Level 3 (mapped) images of above segments in Mercator or other projection (e.g., Polar Stereographic for Alaska).
Level 3 (mapped) data product in GeoTIFF format (for USGS GIS applications)
Automatically generated and disseminated alerts when volcanic emissions detected by the OMI and AIRS algorithms
Products of interest with longer latencies
SO2 and Volcanic Ash multiple orbit (composite) images
SO2 tonnages
SO2 and ash cloud heights (may eventually become NRT products)
** Until then, we depend on Simon and Arlin **

7. From TOMS, we know that SO2 in the atmosphere is a distinctive marker of volcanic activity.
HAZARD INDICATOR -- Eruptive plumes
Volcanoes are the only significant sources of large quantities of SO2 gas in the stratosphere (jet-cruising altitudes) and may indicate the presence of hazardous ash clouds in the vicinity. ** But SO2 is known to separate from the ash-rich portion of a volcanic cloud, so hazard to aviation when long-lived SO2 cloud is detected can be ambiguous. **
FORECAST INDICATOR -- Pre-eruptive degassing
Volcanoes also emit SO2 into the lower troposphere (below ~5 km) during pre-eruptive or non-eruptive unrest (“passive” degassing). Also during basaltic effusive eruptions such as in Hawaii.
The much better sensitivity and resolution of OMI will give new insights for both these modes.

8. OMI plus RADAR at Fourpeaked Volcano, AK: A long dormant volcano -- last volcanic activity was prior to glaciation (>10,000 years ago). No known fumarolic areas around the volcano.
Homer
(1) Plume observed from Homer on 17 Sept 06. Reached height of ~20,000 ft ASL.

9. (2) OMI detection of SO2 degassing (by Simon Carn) helped AVO to confirm the volcanic nature of the activity.
(But we were lucky to have daylight and no clouds at that moment.)

10. Retrospective confirmation by NEXRAD.
(4) No close in seismic stations.
Small EQ swarm occurred just before RADAR image.
King Salmon NEXRAD

11. ALASKA VOLCANO OBSERVATORY Information Release
ALASKA VOLCANO OBSERVATORY Information Release Wednesday, September 20, :25 PM AKDT (2225 UTC) FOURPEAKED VOLCANO (CAVW# ) 58°46'12" N153°40'19" W, Summit Elevation 6903 ft (2104 m) Current Level of Concern Color Code: YELLOW On Sunday evening, September 17, AVO received numerous reports of a large unusual cloud rising to heights of 20,000 ft (6,000 m) above sea level from the Cape Douglas area, about 200 miles (320 km) southwest of Anchorage and about 80 miles (140 km) northwest of Kodiak. Since our Monday, September 18 Information Release, additional data and observations of the September 17 event have been compiled from several new sources. These data confirm that the source of the large cloud observed Sunday evening was volcanic. Thus, AVO is increasing the Level of Concern Color Code for Fourpeaked volcano from “Not Assigned” to YELLOW New details of Sunday’s event have been added since Monday afternoon. Retrospective analysis of data from the NEXRAD Doppler radar in King Salmon show an unusual cloud starting at 12:00 PM AKDT (2000 UTC) on September 17. The maximum cloud height determined by radar during the first hour of the event was 20,000 ft (6,000 m). The radar return from the cloud continued until at least 9:45PM AKDT (0545 UTC). A cloud of sulfur dioxide gas released during the eruption was observed by colleagues at the University of Maryland Baltimore County over Cape Douglas/Fourpeaked region on September 17, 2006 at 3:00PM AKDT (2300 UTC) using data collected by the Ozone Monitoring Instrument (OMI) on NASA’s Aura satellite. Puff particle dispersion modeling showed that the cloud would have spread west to east as it moved northwards over the subsequent day. This is consistent with pilot reports received by AVO on the afternoon of Monday, September 18, that described a strong sulfur smell in the Stony River Valley, 300 km (180 miles) northwest of the Fourpeaked area, and from additional OMI sulfur dioxide observations of the cloud. Although poor weather in the area has prevented visual observations, NEXRAD data over the past two days have not detected any further emissions. AVO staff will attempt both fixed-winged and helicopter overflights this afternoon to locate the possible vent areas and document any changes. AVO continues to monitor satellite data for further signs of activity.

12. ??? (5) AVO Response: Visual observations of new steam vents
Installation of seismic stations
Gas flights
Infrared cameras
Web cam
???
Has this kind of unrest occurred before and we haven’t noticed it?
Was this the total activity or the beginning of more to come?
We don’t know yet. Stay tuned.

13. Airborne and ground-based measurements
USGS SO2 Monitoring:
Airborne and ground-based measurements
“Gas Flight” -- COSPEC surveys from small aircraft by group based at CVO. Method corrects for wind speed to give tons/day. CO2 and H2S concentrations in plume also measured.
Recently, mini DOAS: small, fiber optic UV diff. optical absorption spect. Mobile (car, foot, hlo) or ground-based scanning.
HVO makes COSPEC measurements from vehicle and operates ground-based SO2 monitoring sites at Kilauea. Difficult in that corrosive environment.
SO2 & aerosol plume (vog) from Kilauea dims the sun.

14. COSPEC data not directly comparable to OMI data
Instantaneous rate measurement that corrects for wind speed to give tons/day.
4Peaked: ~1000 to ~3000 t/d
Elevated but not “off the charts”
OMI
Mass measurement (tons) of the total column abundance present during one orbit (~22 hours). Assumes an altitude that the plume reaches (a lower altitude increases the SO2 amount and vice versa.)
4Peaked: up to ~300 tons in one orbit (~22 hours), assumes plume to altitude of 5 km.

15. A wealth of fruitful collaborative research directions, basic & applied:
Correlation of ground-based and space-based measurements. Need some dedicated experiments to address this issue. Kilauea a good candidate but also a high-latitude, explosive volcano.
Amount and timing of magmatic de-gassing before, during, and after eruptions. Ability to detect and quantify passive degassing at volcanoes worldwide will aid in diagnosing outcome of unrest at a specific volcano -- how many volcanoes degas significant amounts of SO2 without erupting?
Having semi-continuous measurements of SO2 emissions (mass) during an eruption gives ~time-series data that can be correlated with geophysical time series data on eruptive processes.
Clearer delineation of volcanic clouds, including their ash-poor edges -- has implications for validation of ash dispersion models.
Separation over time of SO2 clouds from ash clouds, which has hazard implications -- how dangerous to aircraft are SO2 clouds?