Neural network multispectral satellite images classification of volcanic ash plumes in a cloudy scenario

• Published in: Annals of Geophysics
• Main Authors: Matteo Picchiani, Marco Chini, Stefano Corradini, Luca Merucci, Alessandro Piscini, Fabio Del Frate
• Format: Article in Journal/Newspaper
• Language: English
• Published: Istituto Nazionale di Geofisica e Vulcanologia (INGV) 2015
• Subjects: Neural Networks; Volcanic Ash detection; BTD; Meteorology. Climatology; QC851-999; Geophysics. Cosmic physics; QC801-809; Jökull; Eyjafjallajökull
• Online Access: https://doi.org/10.4401/ag-6638; https://doaj.org/article/9efbea6f566d43bb9085e707483499b3

This work shows the potential use of neural networks in the characterization of eruptive events monitored by satellite, through fast and automatic classification of multispectral images. The algorithm has been developed for the MODIS instrument and can easily be extended to other similar sensors. Six classes have been defined paying particular attention to image regions that represent the different surfaces that could possibly be found under volcanic ash clouds. Complex cloudy scenarios composed by images collected during the Icelandic eruptions of the Eyjafjallajökull (2010) and Grimsvötn (2011) volcanoes have been considered as test cases. A sensitivity analysis on the MODIS TIR and VIS channels has been performed to optimize the algorithm. The neural network has been trained with the first image of the dataset, while the remaining data have been considered as independent validation sets. Finally, the neural network classifier’s results have been compared with maps classified with several interactive procedures performed in a consolidated operational framework. This comparison shows that the automatic methodology proposed achieves a very promising performance, showing an overall accuracy greater than 84%, for the Eyjafjalla - jökull event, and equal to 74% for the Grimsvötn event.