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Real time retrieval of volcanic cloud particles and SO<sub>2</sub> by satellite using an improved simplified approach
Language
English
Obiettivo Specifico
Status
Published
JCR Journal
JCR Journal
Peer review journal
Yes
Title of the book
Issue/vol(year)
/9 (2016)
Pages (printed)
3053–3062
Issued date
2016
Abstract
Volcanic plume removal (VPR) is a procedure developed
to retrieve the ash optical depth, effective radius and
mass, and sulfur dioxide mass contained in a volcanic cloud
from the thermal radiance at 8.7, 11, and 12 μm. It is based on
an estimation of a virtual image representing what the sensor
would have seen in a multispectral thermal image if the volcanic
cloud were not present. Ash and sulfur dioxide were
retrieved by the first version of the VPR using a very simple
atmospheric model that ignored the layer above the volcanic
cloud. This new version takes into account the layer of atmosphere
above the cloud as well as thermal radiance scattering
along the line of sight of the sensor. In addition to improved
results, the new version also offers an easier and faster
preliminary preparation and includes other types of volcanic
particles (andesite, obsidian, pumice, ice crystals, and water
droplets). As in the previous version, a set of parameters
regarding the volcanic area, particle types, and sensor is required
to run the procedure. However, in the new version,
only the mean plume temperature is required as input data. In
this work, a set of parameters to compute the volcanic cloud
transmittance in the three quoted bands, for all the aforementioned
particles, for both Mt. Etna (Italy) and Eyjafjallajökull
(Iceland) volcanoes, and for the Terra and Aqua MODIS instruments
is presented. Three types of tests are carried out
to verify the results of the improved VPR. The first uses all
the radiative transfer simulations performed to estimate the
above mentioned parameters. The second one makes use of
two synthetic images, one for Mt. Etna and one for Eyjafjallajökull
volcanoes. The third one compares VPR and Look-
Up Table (LUT) retrievals analyzing the true image of Eyjafjallajökull
volcano acquired by MODIS aboard the Aqua
satellite on 11 May 2010 at 14:05GMT.
to retrieve the ash optical depth, effective radius and
mass, and sulfur dioxide mass contained in a volcanic cloud
from the thermal radiance at 8.7, 11, and 12 μm. It is based on
an estimation of a virtual image representing what the sensor
would have seen in a multispectral thermal image if the volcanic
cloud were not present. Ash and sulfur dioxide were
retrieved by the first version of the VPR using a very simple
atmospheric model that ignored the layer above the volcanic
cloud. This new version takes into account the layer of atmosphere
above the cloud as well as thermal radiance scattering
along the line of sight of the sensor. In addition to improved
results, the new version also offers an easier and faster
preliminary preparation and includes other types of volcanic
particles (andesite, obsidian, pumice, ice crystals, and water
droplets). As in the previous version, a set of parameters
regarding the volcanic area, particle types, and sensor is required
to run the procedure. However, in the new version,
only the mean plume temperature is required as input data. In
this work, a set of parameters to compute the volcanic cloud
transmittance in the three quoted bands, for all the aforementioned
particles, for both Mt. Etna (Italy) and Eyjafjallajökull
(Iceland) volcanoes, and for the Terra and Aqua MODIS instruments
is presented. Three types of tests are carried out
to verify the results of the improved VPR. The first uses all
the radiative transfer simulations performed to estimate the
above mentioned parameters. The second one makes use of
two synthetic images, one for Mt. Etna and one for Eyjafjallajökull
volcanoes. The third one compares VPR and Look-
Up Table (LUT) retrievals analyzing the true image of Eyjafjallajökull
volcano acquired by MODIS aboard the Aqua
satellite on 11 May 2010 at 14:05GMT.
Type
article
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