SATELLITE REMOTE SENSING OF VOLCANIC AEROSOLS: A NEW, AVHRR-BASED, APPROACH

Through this paper the authors propose a new approach for volcanic aerosols detection by satellite. By using only NOAA/AVHRR data at hands the proposed method seems able to detect eruptive volcanic clouds as well as long-period trends in stratospheric aerosol loading related to major eruptive events. Several examples of application to different events of volcanic emission (developing with different space/time dynamics) are presented; some cases of Etna and Stromboli volcanoes have been investigated and an historical analysis has been performed in order to recognize stratospheric aerosols produced by Mount Pinatubo's eruption. In all cases the technique was able to detect anomalous particle loading in atmosphere, in an automatic way, without need of any specific transmittance model for the atmosphere or ancillary ground-based measurements. The main merit of this new approach is its effectiveness in recognizing field anomalies also in the presence of a highly variable background as well as its intrinsic exportability ensured by the use of thresholds which are local (i.e. specific for the time and the place of the observation) but automatically generated by using only satellite data at hands. By this way the proposed technique can be numbered among the others environmental applications of RAT(1) (Robust AVHRR Technique) approach in which it finds its origin.