A New Approach to Fog Detection Using Seviri and Modis Data

Meteosat 8 SEVIRI with its good spectral, spatial and temporal resolutions provides an excellent basis for the monitoring and nowcasting of fog. Based on this the present study outlines a method for fog detection using SEVIRI data, with algorithms for both, night and daytime. The night algorithm is ported from NOAA AVHRR and relies on brightness temperature differences between the 10.8 and 3.9 μm channels. The daytime method relies on the spatial evaluation cloud cluster features: Based on a gross water cloud check, spatially discrete and homogeneous cloud patches are tested for their elevation and homogeneity. Where a set of criteria is met, a cloud cluster is identified as fog / low stratus. In first analyses the method shows encouraging results. A number of sample classifications are introduced and discussed.