Abstract:
A 10-year fog climatology of Germany and adjacent areas, based on NOAA-Advanced Very
High-Resolution Radiometer (AVHRR) data, is presented. Maximum fog frequency is obtained for
the Lake Constance area; minimum fog occurrence, accounting for basins and river valleys, is
located in the Lower Rhine area. This is a transition zone between coastal advection fog and the more
continental radiation fog of the lower mountain range. Fog persistence is estimated by a comparison
of night and day maps. Using the bispectral approach of Nakajima and Nakajima [J. Atmos. Sci. 52,
(1995) 4043], the potential of weather satellite data for climatologies of fog’s optical and
microphysical properties is examined. Maps of fog optical depth, effective radius and liquid water
path (LWP) are computed from well-illuminated noon images and the resulting data set is statistically
evaluated. Typical features of advection fog are obtained for the coastal areas of the North and Baltic
Seas, while the fog of the pre-Alpine basins reveals characteristics of continental radiation fog. The
results are in general accordance with field observations of various sources.
