1 research outputs found
Multisatellite Multisensor Observations of a Sub-Plinian Volcanic Eruption: The 2015 Calbuco Explosive Event in Chile
A-train satellite data, acquired during the Calbuco
volcano (Chile) sub-Plinian eruption in April 2015, are discussed
to explore the complementarity of spaceborne observations
in the microwave (MW), thermal infrared (TIR), and visible
wavelengths for both near-source plume and distal ash clouds.
The analysis shows that TIR-based detection techniques are
not suitable near the volcanic vent where rising convective
columns are associated with large optical depths. Detection and
parametric estimates of near-source tephra mass loading and
plume height from MW radiometric data, available 69 min after
the eruption onset, are proposed. Results indicate a maximum
plume altitude of about 21 km above the sea level and an
ash mass of 3.65 × 10^10 kg, in agreement with mass values
obtained from empirical formulas, but less than proximal–
distal mass deposit of 1.86 × 10^11 kg. This discrepancy may
be explained by extrapolating Advanced Technology Microwave
Sounder-based estimates to 6 h, thus obtaining a total mass of
about 1.90×10^11 kg. Distal volcanic cloud retrievals are derived
from TIR imagery and results show a good agreement between
Moderate-Resolution Imaging Spectroradiometer (MODIS) and
Visible Infrared Imaging Radiometer Suite (VIIRS) retrievals
of total mass taking into account the overpass time shift.
If only the overlapping pixels between MODIS and VIIRS
are considered, the respective estimates are 1.90 × 10^9 kg and
1.80 × 10^9 kg. TIR radiometric estimates of distal ash cloud
height and mass loadings are also compared with Cloud-Aerosol
Lidar and Infrared Pathfinder Satellite Observations lidar retrievals. For low-to-medium optically thick ash cloud, average Cloud-Aerosol Lidar with Orthogonal Polarization-derived mass
loading is about 0.8 g/m2 against 0.4 g/m2 from VIIRS and 1.4 g/m2 from MODIS.Published2597 - 26126V. Pericolosità vulcanica e contributi alla stima del rischio6SR VULCANI – Servizi e ricerca per la società JCR Journa