A New Approach for Detecting and Monitoring Saharan Dusts from Space

The Saharan region has long been indicated as the main source in the world of soil dust in the atmosphere. Saharan dust storms are particularly investigated because they represent a potential risk for human health and cause damages and disruptions to the transport routes and communication. They can have direct implications (strictly related to the desertification processes affecting the Sub Saharan region) on the Earth’s climatic system and/or on the precipitation regimes. In recent years, in addition to the ground monitoring systems, several satellite techniques have been proposed to detect and monitor Saharan dust clouds. The success of these methodologies, as those exploiting the reverse absorption behaviour shown by silicate particles, in comparison with ice crystals and water droplets, at 11 and 12 µm wavelengths (split-window), is strongly dependent on the observational conditions (day/night, land/sea, etc.) and on the specific aerosol properties (mainly size distribution and complex refractive index). In particular, although dust and meteorological clouds generally show a different spectral behaviour in the split window bands, an effective discrimination of these features still represent a major issue. In this paper, a Robust Satellite data analysis Technique (RST), which already highlighted good performances in detecting desert dust aerosol, has been further tested, analyzing an important Saharan dust event affecting Mediterranean basin in May 2010, with results compared to those provided by two traditional split window methods. Outcomes of this study, achieved using, for the first time, daytime infrared MSG-SEVIRI (Meteosat Second Generation-Spinning Enhanced Visible and Infra-red Imager) data, confirm that RST, thanks to a good trade-off between sensitivity and reliability of detection, may profitably be used for monitoring Saharan dust events from space in different observational conditions.