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Detection and nowcasting of fog. An operational nowcasting modul Ch09: 10.8 Ch04: 3.9 difference channel: 04 - 09 Differences for difference channel between to points of time: measure for development and dissipation of fog. Contact person: Veronika Zwatz-Meise
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Detection and nowcasting of fog An operational nowcasting modul Ch09: 10.8 Ch04: 3.9 difference channel: 04 - 09 Differences for difference channel between to points of time: measure for development and dissipation of fog Contact person: Veronika Zwatz-Meise zwatz-meise@zamg.ac.at Version 1.0. 13 July 2004
Ch04; not inverted, clouds are dark
Difference 04 - 09 green: high probability for fog
Difference 02 - 03 UTC blue: automatic diagnosis of areas colder than -7o green: areas with „fog development“ during the last hour red: areas with „fog disspation“ during the last hour
Difference 04 - 09 02 UTC
Difference 04 - 09 03 UTC Fog develops and/or becomes denser Fog dissipates
Computation of differences between two points of time • Two possible interpretations: • Fog fields without moving upper level clouds: • Fog development and/or dissipation • Fog fields with moving/crossing upper level cloud: • New detection and/or hiding of fog through crossing upper level cloud fields • this is especially true for the boundary areas between fog and high cloud