Fog, air exchange and air quality in the Alpine region. Remote sensing applications in mountain climatology

Abstract

Procedures based on digitral NOAA-AVHRR data and results are presented:1) The discrimination of fog and other surfaces by means of a thresholdtechnique. 2) By the superposition of a data set with the coordinatesof the fog boundary and a digital elevation model the elevation ofthe upper fog limit can be determined. 3) Visibility and liquid watercontent of the fog layer highly correlate with the daytime signalof channel 3 ((3.7 [mu]m). 4) Regional aspects of horizontal flowpatterns and air mass exchanges in the boundary layer are evaluatedby a combined use of a mesoscale model and the respective satellitedata. Maps of the following climatological phenomena for the SwissPlateau and the Po Valley have been produced and are discussed inthe paper: Spatial distribution and frequency of the fog layers,frequency of their marginal position, fog persistence, visibilityand liquid water content as well as potential risk of immission dueto damp deposition. -from English summary [Journal; map; In German]