A multi-sensor approach for volcanic ash cloud retrieval and eruption characterization: The 23 November 2013 Etna lava fountain

摘要

Volcanic activity is observed worldwide with a variety of ground and space-based\udremote sensing instruments, each with advantages and drawbacks. No single system can give\uda comprehensive description of eruptive activity, and so, a multi-sensor approach is required. This\udwork integrates infrared and microwave volcanic ash retrievals obtained from the geostationary\udMeteosat Second Generation (MSG)-Spinning Enhanced Visible and Infrared Imager (SEVIRI),\udthe polar-orbiting Aqua-MODIS and ground-based weather radar. The expected outcomes are\udimprovements in satellite volcanic ash cloud retrieval (altitude, mass, aerosol optical depth and\udeffective radius), the generation of new satellite products (ash concentration and particle number\uddensity in the thermal infrared) and better characterization of volcanic eruptions (plume altitude,\udtotal ash mass erupted and particle number density from thermal infrared to microwave). This\udapproach is the core of the multi-platform volcanic ash cloud estimation procedure being developed\udwithin the European FP7-APhoRISM project. The Mt. Etna (Sicily, Italy) volcano lava fountaining\udevent of 23 November 2013 was considered as a test case. The results of the integration show the\udpresence of two volcanic cloud layers at different altitudes. The improvement of the volcanic ash\udcloud altitude leads to a mean difference between the SEVIRI ash mass estimations, before and after\udthe integration, of about the 30%. Moreover, the percentage of the airborne “fine” ash retrieved from\udthe satellite is estimated to be about 1%–2% of the total ash emitted during the eruption. Finally,\udall of the estimated parameters (volcanic ash cloud altitude, thickness and total mass) were also\udvalidated with ground-based visible camera measurements, HYSPLIT forward trajectories, Infrared\udAtmospheric Sounding Interferometer (IASI) satellite data and tephra deposits.