Volcanic ash retrieval at Mt. Etna using Avhrr and Modis data

Abstract

The volcanic ash detection procedures are based on Brightness Temperature Difference (BTD) algorithm using the thermal infrared channels centred around 11 and 12 microns of a multispectral satellite sensor. The Mie code has been is included in the retrieval procedure to compute the ash optical properties from the ash microphysical characteristics. The simulations has been carried out using MODTRAN radiative transfer model. The Nasa-Modis and the Noaa-Avhrr measurements of Mt. Etna eruptive plume occurred in November 2006 have been analyzed to retrieve the plume optical thickness, the particle effective radius and the size distribution.