Example of Fog over Northern Europe

24 Feb 2004; a winter case, fog over cold 24 Feb 2004; a winter case, fog over cold snow surfacesnow surface

29 May 2004; fog over sea drifting ashore29 May 2004; fog over sea drifting ashore

Pirkko PylkköFinnish Meteorological Institute

(See alsowww.knmi.nl/satrep Satrep Manual)

1/30.6.2004

Winter case; 24 Feb 2004

Fog over snow surface:•Fog top warmer than surrounding snow surface => in IR channels fog darker than surface•In the winter mostly nighttime or twilight conditions•10.8 and 12µm channels better than 3.9µm for fog above cold snow at night•Next pages: First AVHRR 10.8 and 3.8µm images and then same channels from SEVIRI (date 24 Feb 2004 0130UTC)

2/30.6.2004

AVHRR 10.8µm

Fog

Fog

AVHRR 3.7µm

SEVIRI 10.8 µm

Fog

SEVIRI 3.9µm

Fog

7/30.6.2004

Fog over sea; 29 May 2004•Daytime fog can be seen also in visible channels very well•SEVIRI HRV can be of assistance also in the north•Animating SEVIRI images makes fog more easy to recognize•Following pages: SEVIRI 1.6, 0.8 and 0.6 µm

AVHRR channels 0.6, 0.8, 10.8µm

SEVIRI 1.6, 0.8, 0.6 µm combination29 May 2004 1345UTC

SEVIRI 1.6, 0.8, 0.6 µm combination29 May 2004 1400UTC

SEVIRI 1.6, 0.8, 0.6 µm combination29 May 2004 1430UTC

SEVIRI 1.6, 0.8, 0.6 µm combination29 May 2004 1500UTC

SEVIRI 1.6, 0.8, 0.6 µm combination29 May 2004 1515UTC

SEVIRI 1.6, 0.8, 0.6 µm combination29 May 2004 1530UTC

SEVIRI 1.6, 0.8, 0.6 µm combination29 May 2004 1545UTC

SEVIRI 1.6, 0.8, 0.6 µm combination29 May 2004 1600UTC