M.S. Project
This is the
abstract from my M.S. Thesis:
At an elevation of
813 m, Miyakejima (Mt. Oyama), a basaltic andesite stratovolcano, is located
approximately 200 km south of Tokyo. Two significant eruptions occurred in
August 2000 and were detected by multiple satellite sensors. Satellite images
were obtained for the day of the eruption and only the three days following due
to the small scale of the eruptions. For both eruptions, the cloud can be
observed with high confidence for two days. In this study, 8 TOMS, 7 MODIS, 6
AVHRR, and 8 days of hourly GMS images are compared and used to produce
constraints on the masses and distributions of ash and SO2 released
by the eruptions.
The 18 August
eruption at 08:02 UTC (17:02 JST) emitted an ash cloud of at least 511,000
metric tons and SO2 cloud of 43 kilotons to a height of
approximately 16 km, which then drifted south. TOMS satellite imagery (00:40
UTC) suggests a separation of ash and gas associated with the eruption. This
eruption may represent a vent clearing based on the large amounts of ash and
gas in comparison to later events. The 28 August eruption (19:35 UTC, 04:35 JST)
was smaller with a cloud containing a minimum of 200 metric tons of ash and 21
kilotons of SO2 at a maximum height of 5 km to the northeast of the
volcano.
Comparisons of
detection ability of sensors were also made. Results suggest that ultraviolet (TOMS)
is more sensitive to SO2 or is at least less prone to interferences
of water vapor and other species as observed with the infrared sensor (MODIS). TOMS
was able to detect SO2 for a total of 5 days for both eruptions
combined, while MODIS detected the gas for one day of each eruption. GMS was
the most consistent when detecting ash and was able to see ash clouds not
detected by the other sensors. Also, because the satellite is geostationary
measurements are taken more frequently (hourly) versus once or twice daily. These
findings imply that infrared geostationary sensors are and will be the most
effective in mitigating aircraft encounters with volcanic ash clouds.
Below are
some helpful links which detail the development of my research project:
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Miyakejima (34.08 E, 139.53 N) Photo courtesy of Yasuhiro Kamada |
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