Use of IR3.9 and IR8.7 channels for fog nowcasting
Competency Framework
WMO Satellite Skills
Application
Description
Presentation during the event week on Fog and Low Clouds in January 2009.
Content
Anna Eronn from the Swedish Hydrological and Meteorological Institute will talk about cold event Fog.
The most common way to detect fog and low clouds at night is by using of the brightness temperature difference between IR10.8 and IR3.9. Unfortunately this method does not work in very cold winter situations because the IR3.9 channel is very noisy for cold scenes. Therefore it is recommended to replace the IR3.9 with the IR8.7 channel which is significantly less noisy for cold scenes. The theory behind this and practical examples will be presented.