APPLICATIONS OF
METEOSAT SECOND
GENERATION (MSG)
FOG DETECTION
Author:
Jochen Kerkmann (EUMETSAT)
(kerkmann@eumetsat.de)
Contributors: H. J. Lutz (EUMETSAT), P. Pylkkö (FMI),
HP. Roesli (MeteoSwiss), D. Rosenfeld (HUJ)
Version 1.0, 14 May 2004
Slide: 1
Day-time Fog over Southern Germany
24 February 2003
Version 1.0, 14 May 2004
Slide: 2
1
MSG-1
24 Feb 2003
11:00 UTC
Channel 09
(IR10.8)
2
3
1 1
2
1= low-level fog or
stratus
2= snow
3
1
1
3 = snow-free
ground
IR10.8 channel not very useful for fog detection
Version 1.0, 14 May 2004
Slide: 3
1
MSG-1
24 Feb 2003
11:00 UTC
Channel 04
(IR3.9)
2
3
1 1
2
1= low-level fog or
stratus
2= snow
3
1
1
3 = snow-free
ground
Detection of fog during day-time much better with IR3.9 channel
Version 1.0, 14 May 2004
Slide: 4
1
MSG-1
24 Feb 2003
11:00 UTC
Channel 04r
(IR3.9r)
2
3
1 1
2
1= low-level fog or
stratus
2= snow
3
1
1
3 = snow-free
ground
Detection of fog during day-time also good with solar component of IR3.9
Version 1.0, 14 May 2004
Slide: 5
1
MSG-1
24 Feb 2003
11:00 UTC
Difference
IR3.9 - IR10.8
2
3
1 1
2
1= low-level fog or
stratus
2= snow
3
1
1
3 = snow-free
ground
… or with the brightness temperature difference IR3.9 - IR10.8
Version 1.0, 14 May 2004
Slide: 6
1
3
2
11 2
3
Detection of fog over
snow surfaces with
SEVIRI NIR 1.6 channel
24 Feb 2003, 11:00 UTC
High reflectance
(water clouds)
1
1
Lower reflectance
(ice clouds)
Low reflectance
(snow, sea)
Version 1.0, 14 May 2004
Slide: 7
Animation 1/5
2
1
1
2
Detection of fog over
snow surfaces with
SEVIRI NIR 1.6 channel
1= low-level fog or stratus
2= snow
2
3= thin mid-level cloud with
water droplets
(supercooled cloud)
3
4= lakes
4
Version 1.0, 14 May 2004
MSG-1
24 Feb 2003
11:00 UTC
Channel 03
(NIR1.6)
Slide: 8
Animation 2/5
2
1
1
2
Detection of fog over
snow surfaces with
SEVIRI NIR 1.6 channel
1= low-level fog or stratus
2= snow
2
3= thin mid-level cloud with
water droplets
(supercooled cloud)
3
4= lakes
4
Version 1.0, 14 May 2004
MSG-1
24 Feb 2003
11:15 UTC
Channel 03
(NIR1.6)
Slide: 9
Animation 3/5
2
1
1
2
Detection of fog over
snow surfaces with
SEVIRI NIR 1.6 channel
1= low-level fog or stratus
2= snow
2
3= thin mid-level cloud with
water droplets
(supercooled cloud)
3
4= lakes
4
Version 1.0, 14 May 2004
MSG-1
24 Feb 2003
11:30 UTC
Channel 03
(NIR1.6)
Slide: 10
Animation 4/5
2
1
1
2
Detection of fog over
snow surfaces with
SEVIRI NIR 1.6 channel
1= low-level fog or stratus
2= snow
2
3= thin mid-level cloud with
water droplets
(supercooled cloud)
3
4= lakes
4
Version 1.0, 14 May 2004
MSG-1
24 Feb 2003
11:45 UTC
Channel 03
(NIR1.6)
Slide: 11
Animation 5/5
2
1
1
2
Detection of fog over
snow surfaces with
SEVIRI NIR 1.6 channel
1= low-level fog or stratus
2= snow
2
3= thin mid-level cloud with
water droplets
(supercooled cloud)
3
4= lakes
4
Version 1.0, 14 May 2004
MSG-1
24 Feb 2003
12:00 UTC
Channel 03
(NIR1.6)
Slide: 12
MSG-1, 24 Feb 2004,
11:00 UTC, VIS0.8
… close-up view
over the Alps
Non-detection of fog
over snow surfaces with
SEVIRI VIS0.6 amd
VIS0.8 channels
Version 1.0, 14 May 2004
Slide: 13
MSG-1, 24 Feb 2004,
11:00 UTC, HRV
… close-up view
over the Alps
Non-detection of fog
over snow surfaces with
SEVIRI HRV channel
Version 1.0, 14 May 2004
Slide: 14
1
MSG-1
24 Feb 2003
11:00 UTC
RGB Composite
R = NIR1.6
G = VIS0.8
B = VIS0.6
1
2
1
2
2
1
1
3
1= low-level fog
or stratus
2= snow
3= thin mid-level
cloud with
water droplets
(supercooled
cloud)
Recommended RGBs for Monitoring of Day-time Fog
Version 1.0, 14 May 2004
Slide: 15
1
MSG-1
24 Feb 2003
11:00 UTC
RGB Composite
R = VIS0.8
G = IR3.9r
B = IR10.8
1
2
1
2
2
1
1
3
1= low-level fog
or stratus
2= snow
3= thin mid-level
cloud with
water droplets
(supercooled
cloud)
Recommended RGBs for Monitoring of Day-time Fog
Version 1.0, 14 May 2004
Slide: 16
1
MSG-1
24 Feb 2003
11:00 UTC
RGB Composite
R = VIS0.8
G = NIR1.6
B = IR3.9r
1
2
1
2
2
1
1
3
1= low-level fog
or stratus
2= snow
3= thin mid-level
cloud with
water droplets
(supercooled
cloud)
Recommended RGBs for Monitoring of Day-time Fog
Version 1.0, 14 May 2004
Slide: 17
1
1
2
MSG-1
24 Feb 2003
11:45 UTC
RGB Composite
R = NIR1.6
G = HRV
B = HRV
1= low-level fog or stratus
2= snow
2
3
Version 1.0, 14 May 2004
3= thin mid-level cloud with
water droplets (supercooled
cloud)
Recommended RGBs
for Monitoring of
Day-time Fog
Slide: 18
Night-time Fog over France
14 July 2003
Version 1.0, 14 May 2004
Slide: 19
Animation 1/4
Detection of fog at night
(and day) with
IR3.9 - IR10.8
brightness temp. diff.
2
1= low-level fog or stratus
2= clear ground
1
3
Version 1.0, 14 May 2004
3= high-level clouds
MSG-1
14 July 2003
03:00 UTC
Difference Image
IR3.9 - IR10.8
Slide: 20
Animation 2/4
Detection of fog at night
(and day) with
IR3.9 - IR10.8
brightness temp. diff.
2
1= low-level fog or stratus
2= clear ground
1
3
Version 1.0, 14 May 2004
3= high-level clouds
MSG-1
14 July 2003
04:00 UTC
Difference Image
IR3.9 - IR10.8
Slide: 21
Animation 3/4
2
Detection of fog at night
(and day) with
IR3.9 - IR10.8
brightness temp. diff.
Detection of fog difficult
at dawn/dusk !
1= low-level fog or stratus
2= clear ground
1
3
Version 1.0, 14 May 2004
3= high-level clouds
MSG-1
14 July 2003
05:00 UTC
Difference Image
IR3.9 - IR10.8
Slide: 22
Animation 4/4
Detection of fog at night
(and day) with
IR3.9 - IR10.8
brightness temp. diff.
2
1= low-level fog or stratus
2= clear ground
1
3
Version 1.0, 14 May 2004
3= high-level clouds
MSG-1
14 July 2003
06:00 UTC
Difference Image
IR3.9 - IR10.8
Slide: 23
MSG-1, 14 July 2003
Difference IR3.9 - IR10.8, 2:00 UTC
Version 1.0, 14 May 2004
HRVIS for comparison, 08:45 UTC
Slide: 24
Night-time Fog over S. Africa
24 April 2003
Version 1.0, 14 May 2004
Slide: 25
3
IR10.8 channel not
useful for fog detection
during night-time
1
2
4
Version 1.0, 14 May 2004
1= low-level fog or stratus
2= clear ground
3 = thin mid-level clouds
4 = thick high-level clouds
MSG-1
24 April 2003
02:00 UTC
Channel 09
(IR10.8)
Slide: 26
3
IR8.7 channel also not
useful for fog detection
during night-time
1
2
4
Version 1.0, 14 May 2004
1= low-level fog or stratus
2= clear ground
3 = thin mid-level clouds
4 = thick high-level clouds
MSG-1
24 April 2003
02:00 UTC
Channel 07
(IR8.7)
Slide: 27
3
IR3.9 channel also not
useful for fog detection
during night-time
1
2
4
Version 1.0, 14 May 2004
1= low-level fog or stratus
2= clear ground
3 = thin mid-level clouds
4 = thick high-level clouds
MSG-1
24 April 2003
02:00 UTC
Channel 04
(IR3.9)
Slide: 28
Fog at night visible in
IR3.9 - IR10.8
brightness temperature
difference images
3
1
2
4
Version 1.0, 14 May 2004
1= low-level fog or stratus
2= clear ground
3 = thin mid-level clouds
4 = thick high-level clouds
MSG-1
24 April 2003
02:00 UTC
Difference Image
IR3.9 - IR10.8
Slide: 29
Fog at night less visible
in IR8.7 - IR10.8
brightness temperature
difference images
3
1
2
4
Version 1.0, 14 May 2004
1= low-level fog or stratus
2= clear ground
3 = thin mid-level clouds
4 = thick high-level clouds
MSG-1
24 April 2003
02:00 UTC
Difference Image
IR8.7 - IR10.8
Slide: 30
Fog at night not visible
in IR12.0 - IR10.8
brightness temperature
difference images
3
1
2
4
Version 1.0, 14 May 2004
1= low-level fog or stratus
2= clear ground
3 = thin mid-level clouds
4 = thick high-level clouds
MSG-1
24 April 2003
02:00 UTC
Difference Image
IR12.0 - IR10.8
Slide: 31
MSG-1
24 April 2003
02:00 UTC
RGB Composite
R = IR12.0 - IR10.8
G = IR10.8 - IR3.9
B = IR10.8
3
1
2
1= low-level fog or stratus
2= clear ground
3 = thin mid-level clouds
4 = thick high-level clouds
4
Version 1.0, 14 May 2004
Recommended RGB
for Monitoring of
Night-time Fog
Slide: 32
Night-time Fog over Central Europe
25 October 2003
Version 1.0, 14 May 2004
Slide: 33
IR10.8 channel not useful
for fog detection
during night-time
3
1
1
2
2
1= low-level fog or stratus
2= clear ground
3 = thin Cirrus clouds
3
Version 1.0, 14 May 2004
MSG-1
25 October 2003
02:00 UTC
Channel 09
(IR10.8)
Slide: 34
IR8.7 channel also not
useful for fog detection
during night-time
3
1
1
2
2
1= low-level fog or stratus
2= clear ground
3 = thin Cirrus clouds
3
Version 1.0, 14 May 2004
MSG-1
25 October 2003
02:00 UTC
Channel 07
(IR8.7)
Slide: 35
3
1
1
2
IR3.9 channel a bit better
for fog detection
during night-time,
but ...
2
1= low-level fog or stratus
2= clear ground
3 = thin Cirrus clouds
3
Version 1.0, 14 May 2004
MSG-1
25 October 2003
02:00 UTC
Channel 04
(IR3.9)
Slide: 36
3
1
1
2
… fog at night
very well visible in
IR3.9-IR10.8 temperature
difference images
Fog: -8/-10 K (black)
Ground: -4/-5 K (grey)
2
1= low-level fog or stratus
2= clear ground
3 = thin Cirrus clouds
3
Version 1.0, 14 May 2004
MSG-1
25 October 2003
02:00 UTC
Difference Image
IR3.9 - IR10.8
Slide: 37
3
1
1
2
… fog at night
also well visible in
IR8.7-IR10.8 temperature
difference images
Fog: -4 K (dark grey)
Ground: -2 K (light grey)
2
1= low-level fog or stratus
2= clear ground
3 = thin Cirrus clouds
3
Version 1.0, 14 May 2004
MSG-1
25 October 2003
02:00 UTC
Difference Image
IR8.7 - IR10.8
Slide: 38
3
1
1
2
… fog at night
not visible in
IR12.0-IR10.8 temperature
difference images
2
1= low-level fog or stratus
2= clear ground
3 = thin Cirrus clouds
3
Version 1.0, 14 May 2004
MSG-1
25 October 2003
02:00 UTC
Difference Image
IR12.0 - IR10.8
Slide: 39
3
1
2
1
MSG-1
25 Oct 2003
02:00 UTC
RGB Composite
R = IR12.0-IR10.8
G = IR10.8-IR3.9
B = IR10.8
2
1= low-level fog
or stratus
2= clear ground
3 = thin Cirrus
clouds
3
Recommended RGB for Monitoring of Night-time Fog
Version 1.0, 14 May 2004
Slide: 40
Night-time Fog over Southern Finland
29 October 2003
Version 1.0, 14 May 2004
Slide: 41
Fog at night
not visible in
IR10.8 images
1
3
1
2
1= low-level fog or stratus
3
2= clear ground
3 = high-level frontal clouds
1
2
Version 1.0, 14 May 2004
MSG-1
29 October 2003
02:00 UTC
Channel 09
(IR10.8)
Slide: 42
Fog at night
not visible in
IR8.7 images
1
3
1
2
1= low-level fog or stratus
3
2= clear ground
3 = high-level frontal clouds
1
2
Version 1.0, 14 May 2004
MSG-1
29 October 2003
02:00 UTC
Channel 07
(IR8.7)
Slide: 43
Fog at night
hardly visible in
IR3.9 images
1
3
1
2
1= low-level fog or stratus
3
2= clear ground
3 = high-level frontal clouds
1
2
Version 1.0, 14 May 2004
MSG-1
29 October 2003
02:00 UTC
Channel 04
(IR3.9)
Slide: 44
Night-time fog
is not well visible in
IR3.9-IR10.8 temperature
difference images over
Scandinavia
1
3
1
2
1= low-level fog or stratus
3
2= clear ground
3 = high-level frontal clouds
1
2
Version 1.0, 14 May 2004
MSG-1
29 October 2003
02:00 UTC
Difference Image
IR3.9 - IR10.8
Slide: 45
The IR8.7-IR10.8
temperature difference
images give better results
for fog detection at high
latitudes
1
3
1
2
1= low-level fog or stratus
3
2= clear ground
3 = high-level frontal clouds
1
2
Version 1.0, 14 May 2004
MSG-1
29 October 2003
02:00 UTC
Difference Image
IR8.7 - IR10.8
Slide: 46
2
3
1
1
3
1
MSG-1
29 Oct 2003
02:00 UTC
RGB Composite
R = IR12.0-IR10.8
G = IR10.8-IR8.7
B = IR10.8
1= low-level fog or
stratus
2
2= clear ground
3 = high-level
frontal clouds
Recommended RGB for Monitoring of Night-time Fog at high Latitudes
Version 1.0, 14 May 2004
Slide: 47
Night-time Fog over Central Europe
5 November 2003
Version 1.0, 14 May 2004
Slide: 48
3
3
Fog at night
not visible in
IR window
channels
2
1= low-level fog or stratus
1
2= clear ground
1
3
2
Version 1.0, 14 May 2004
1
3 = high-level clouds
MSG-1
5 November 2003
03:00 UTC
Channel 04
(IR3.9)
Slide: 49
3
3
Fog at night
not visible in
IR window
channels
2
1= low-level fog or stratus
1
2= clear ground
1
3
2
Version 1.0, 14 May 2004
1
3 = high-level clouds
MSG-1
5 November 2003
03:00 UTC
Channel 07
(IR8.7)
Slide: 50
3
3
Fog at night
not visible in
IR window
channels
2
1= low-level fog or stratus
1
2= clear ground
1
3
2
Version 1.0, 14 May 2004
1
3 = high-level clouds
MSG-1
5 November 2003
03:00 UTC
Channel 09
(IR10.8)
Slide: 51
3
3
Fog at night
well visible in
IR3.9 - IR10.8
difference images
2
Fog: -7/-10 K (black)
Ground: -4 K (grey)
1= low-level fog or stratus
1
2= clear ground
1
3
2
Version 1.0, 14 May 2004
1
3 = high-level clouds
MSG-1
5 November 2003
03:00 UTC
Difference Image
IR3.9 - IR10.8
Slide: 52
3
3
Fog at night
also well visible in
IR3.9 - IR12.0
difference images
2
Fog: -8/-10 K (black)
Ground: -5 K (grey)
1= low-level fog or stratus
1
2= clear ground
1
3
2
Version 1.0, 14 May 2004
1
3 = high-level clouds
MSG-1
5 November 2003
03:00 UTC
Difference Image
IR3.9 - IR12.0
Slide: 53
3
3
Fog at night
also visible in
IR8.7 - IR10.8
difference images
2
Fog: -3/-4 K (dark grey)
Ground: -1 K (light grey)
1= low-level fog or stratus
1
2= clear ground
1
3
2
Version 1.0, 14 May 2004
1
3 = high-level clouds
MSG-1
5 November 2003
03:00 UTC
Difference Image
IR8.7 - IR10.8
Slide: 54
3
3
Fog at night
not visible in
difference
IR12.0 - IR10.8
2
Fog: 0/+1 K (light grey)
Ground: 0/+1 K (light grey)
1= low-level fog or stratus
1
2= clear ground
1
3
2
Version 1.0, 14 May 2004
1
3 = high-level clouds
MSG-1
5 November 2003
03:00 UTC
Difference Image
IR12.0 - IR10.8
Slide: 55
3
3
MSG-1
5 November 2003
03:00 UTC
RGB Composite
R = IR12.0-IR10.8
G = IR10.8-IR3.9
B = IR10.8
2
1
2
1
3
1
1= low-level fog or
stratus
2= clear ground
3 = high-level
clouds
Recommended RGB for Monitoring of Night-time Fog
Version 1.0, 14 May 2004
Slide: 56
Day-time Fog over Central Europe
5 November 2003
Version 1.0, 14 May 2004
Slide: 57
River Valley Fog as seen by Meteosat First Generation (MFG)
Met-7, 5 November 2003, 08:00 UTC, VIS channel
Version 1.0, 14 May 2004
Slide: 58
River valley fog can be
better detected with the
MSG HRV channel
Mosel Valley
Danube Valley
MSG-1
5 November 2003
08:45 UTC
Channel 12
(HRV)
Version 1.0, 14 May 2004
Slide: 59
… and the MSG HRV channel gives more details
Kaiserstuhl
(557 m)
MSG-1
5 November 2003
08:45 UTC
Channel 12
(HRV)
Version 1.0, 14 May 2004
Slide: 60
3
2
1
MSG-1
5 November 2003
09:00 UTC
RGB Composite
R = NIR1.6
G = VIS0.8
B = VIS0.6
1
2
4
1
4
1= low-level fog or
stratus
2= clear ground
3 = high-level
clouds
4 = snow
Recommended RGBs for Monitoring of Day-time Fog
Version 1.0, 14 May 2004
Slide: 61
3
2
MSG-1
5 November 2003
09:00 UTC
RGB Composite
R = VIS0.8
G = IR3.9r
B = IR10.8
1
1
2
4
1= low-level fog or
stratus
2= clear ground
1
4
3 = high-level
clouds
4 = snow
Recommended RGBs for Monitoring of Day-time Fog
Version 1.0, 14 May 2004
Slide: 62
3
2
MSG-1
5 November 2003
09:00 UTC
RGB Composite
R = VIS0.8
G = NIR1.6
B = IR3.9r
1
1
2
4
1= low-level fog or
stratus
2= clear ground
1
4
3 = high-level
clouds
4 = snow
Recommended RGBs for Monitoring of Day-time Fog
Version 1.0, 14 May 2004
Slide: 63
3
MSG-1
5 November 2003
08:45 UTC
RGB Composite
R = HRV
G = HRV
B = IR3.9i
2
1= low-level fog or stratus
1
1
2= clear ground
3 = high-level clouds
4 = snow
4
4
Version 1.0, 14 May 2004
1
2
Recommended RGBs
for Monitoring of
Day-time Fog
Slide: 64
Night-time Fog over Europe
9 November 2003
Version 1.0, 14 May 2004
Slide: 65
Fog at night
not visible in
IR window
channels
1
2
3
1
1= low-level fog or stratus
4
3
2= cold clear ground
1
3 = warm clear ground
(mountains)
4 = thin, high-level clouds
MSG-1
09 November 2003
03:15 UTC
Channel 04
(IR3.9)
Version 1.0, 14 May 2004
Slide: 66
Fog at night
not visible in
IR window
channels
1
2
3
1
1= low-level fog or stratus
4
3
2= cold clear ground
1
3 = warm clear ground
(mountains)
4 = thin, high-level clouds
MSG-1
09 November 2003
03:15 UTC
Channel 07
(IR8.7)
Version 1.0, 14 May 2004
Slide: 67
Fog at night
not visible in
IR window
channels
1
2
3
1
1= low-level fog or stratus
4
3
2= cold clear ground
1
3 = warm clear ground
(mountains)
4 = thin, high-level clouds
MSG-1
09 November 2003
03:15 UTC
Channel 09
(IR10.8)
Version 1.0, 14 May 2004
Slide: 68
Animation 1/6
1
2
Fog: -7/-10 K (black)
Ground: -4/-5 K (grey)
3
1
Fog at night visible in
IR3.9 - IR10.8
difference images
1= low-level fog or stratus
4
3
2= cold clear ground
1
3 = warm clear ground
(mountains)
4 = thin, high-level clouds
MSG-1
09 November 2003
03:15 UTC
Difference Image
IR3.9 - IR10.8
Version 1.0, 14 May 2004
Slide: 69
Animation 2/6
1
2
Fog: -7/-10 K (black)
Ground: -4/-5 K (grey)
3
1
Fog at night visible in
IR3.9 - IR10.8
difference images
1= low-level fog or stratus
4
3
2= cold clear ground
1
3 = warm clear ground
(mountains)
4 = thin, high-level clouds
MSG-1
09 November 2003
04:15 UTC
Difference Image
IR3.9 - IR10.8
Version 1.0, 14 May 2004
Slide: 70
Animation 3/6
1
2
1
Fog at night visible in
IR3.9 - IR10.8
difference images
Fog: -7/-10 K (black)
Ground: -4/-5 K (grey)
3
1= low-level fog or stratus
4
3
2= cold clear ground
1
3 = warm clear ground
(mountains)
4 = thin, high-level clouds
MSG-1
09 November 2003
05:15 UTC
Difference Image
IR3.9 - IR10.8
Version 1.0, 14 May 2004
Slide: 71
Animation 4/6
1
2
1
Fog at dawn/dusk not
visible in IR3.9 - IR10.8
difference images
Fog: -3/-4 K (grey)
Ground: -4/-5 K (grey)
3
1= low-level fog or stratus
3
4
2= cold clear ground
1
3 = warm clear ground
(mountains)
4 = thin, high-level clouds
MSG-1
09 November 2003
06:15 UTC
Difference Image
IR3.9 - IR10.8
Version 1.0, 14 May 2004
Slide: 72
Animation 5/6
1
2
1
Fog at daytime visible in
IR3.9 - IR10.8
difference images
Fog: +2/+6 (light grey)
Ground: -4/-5 K (dark grey)
3
1= low-level fog or stratus
3
4
2= cold clear ground
1
3 = warm clear ground
(mountains)
4 = thin, high-level clouds
MSG-1
09 November 2003
07:15 UTC
Difference Image
IR3.9 - IR10.8
Version 1.0, 14 May 2004
Slide: 73
Animation 6/6
1
2
1
Fog at daytime visible in
IR3.9 - IR10.8
difference images
Fog: +6/+12 (light grey)
Ground: -2/-3 K (dark grey)
3
1= low-level fog or stratus
3
4
2= cold clear ground
1
3 = warm clear ground
(mountains)
4 = thin, high-level clouds
MSG-1
09 November 2003
08:15 UTC
Difference Image
IR3.9 - IR10.8
Version 1.0, 14 May 2004
Slide: 74
Fog at night also
visible in difference
IR8.7 - IR10.8
1
2
Fog: -3/-4 K (black)
Ground: -1/-2 K (grey)
3
1
1= low-level fog or stratus
4
3
2= cold clear ground
1
3 = warm clear ground
(mountains)
4 = thin, high-level clouds
MSG-1
09 November 2003
03:15 UTC
Difference Image
IR8.7 - IR10.8
Version 1.0, 14 May 2004
Slide: 75
Fog at night not visible
in difference
IR12.0 - IR10.8
1
2
Fog: 0/+1 K
Ground: 0/+1 K
Ocean: -1 K
3
1
1= low-level fog or stratus
4
3
2= cold clear ground
1
3 = warm clear ground
(mountains)
4 = thin, high-level clouds
MSG-1
09 November 2003
03:15 UTC
Difference Image
IR12.0 - IR10.8
Version 1.0, 14 May 2004
Slide: 76
MSG-1
9 November 2003
03:15 UTC
RGB Composite
R = IR12.0-IR10.8
G = IR10.8-IR3.9
B = IR10.8
1
2
3
1
4
3
1= low-level fog
or stratus
1
2= cold clear
ground
3 = warm clear
ground
(mountains)
4 = thin, high
level clouds
Recommended RGB for Monitoring of Night-time Fog
Version 1.0, 14 May 2004
Slide: 77
Day-time Fog over Europe
9 November 2003
Version 1.0, 14 May 2004
Slide: 78
Low Stratus and River Valley Fog as seen by MFG
Met-7, 9 November 2003, 08:00 UTC, VIS channel
Version 1.0, 14 May 2004
Slide: 79
MSG HRV channel gives more details on the fog ...
Fog/low stratus
River Valley Fog
Version 1.0, 14 May 2004
MSG-1
9 November 2003
08:15 UTC
Channel 12
(HRV)
Slide: 80
… closer look at Denmark
Fog/Low stratus
with Gravity Waves
Version 1.0, 14 May 2004
MSG-1
9 November 2003
08:15 UTC
Channel 12
(HRV)
Slide: 81
MSG-1
9 November 2003
08:15 UTC
RGB Composite
R = NIR1.6
G = VIS0.8
B = VIS0.6
1
3
1
2
4
4
3
1
4
5
1= low-level fog or
stratus
2= clear ground
1
3 = high-level
thick clouds
2
4 = high-level
thin clouds
5 = snow
Recommended RGBs for Monitoring of Day-time Fog
Version 1.0, 14 May 2004
Slide: 82
MSG-1
9 November 2003
08:15 UTC
RGB Composite
R = VIS0.8
G = IR3.9r
B = IR10.8
1
3
1
2
4
4
3
1
4
5
1= low-level fog or
stratus
2= clear ground
1
3 = high-level
thick clouds
2
4 = high-level
thin clouds
5 = snow
Recommended RGBs for Monitoring of Day-time Fog
Version 1.0, 14 May 2004
Slide: 83
MSG-1
9 November 2003
08:15 UTC
RGB Composite
R = VIS0.8
G = NIR1.6
B = IR3.9r
1
3
1
2
4
4
3
1
4
5
1= low-level fog or
stratus
2= clear ground
1
3 = high-level
thick clouds
2
4 = high-level
thin clouds
5 = snow
Recommended RGBs for Monitoring of Day-time Fog
Version 1.0, 14 May 2004
Slide: 84
3
1
MSG-1
9 November 2003
08:15 UTC
RGB Composite
R = HRV
G = HRV
B = IR3.9 - IR10.8
1
2
4
4
4
1
5
2
1= low-level fog or
stratus
1
2= clear ground
3 = high-level
thick clouds
1
2
4 = high-level
thin clouds
5 = snow
Recommended RGBs for Monitoring of Day-time Fog
Version 1.0, 14 May 2004
Slide: 85
Night-time Fog over Central Europe
11 November 2003
Version 1.0, 14 May 2004
Slide: 86
MSG-1
11 Nov 2003
03:00 UTC
RGB Composite
R = IR12.0 - IR10.8
G = IR10.8 - IR3.9
B = IR10.8
1
2
4
5
3
3
6
1
7
8
7
9
1. Sea surface
2. Land surface
3. Warm fog
4. Cool fog + stratus
(-3oC)
5. Supercooled water
stratus (-13oC)
6. Highly supercooled
water stratus (-18oC)
7. Cb with lightning
8. Thick cirrus
9. Thin cirrus
Recommended RGB for Monitoring of Night-time Fog
Version 1.0, 14 May 2004
Slide: 87
MSG-1
11 Nov 2003
03:00 UTC
Difference Image
R = IR12.0 - IR10.8
1
2
4
5
3
3
6
1
7
8
7
9
1. Sea surface
2. Land surface
3. Warm fog
4. Cool fog + stratus
(-3oC)
5. Supercooled water
stratus (-13oC)
6. Highly supercooled
water stratus (-18oC)
7. Cb with lightning
8. Thick cirrus
9. Thin cirrus
Recommended RGB for Monitoring of Night-time Fog
Version 1.0, 14 May 2004
Slide: 88
MSG-1
11 Nov 2003
03:00 UTC
Difference Image
G = IR10.8 - IR3.9
1
2
4
5
3
3
6
1
7
8
7
9
1. Sea surface
2. Land surface
3. Warm fog
4. Cool fog + stratus
(-3oC)
5. Supercooled water
stratus (-13oC)
6. Highly supercooled
water stratus (-18oC)
7. Cb with lightning
8. Thick cirrus
9. Thin cirrus
Recommended RGB for Monitoring of Night-time Fog
Version 1.0, 14 May 2004
Slide: 89
MSG-1
11 Nov 2003
03:00 UTC
Difference Image
B = IR10.8
1
2
4
5
3
3
6
1
7
8
7
9
1. Sea surface
2. Land surface
3. Warm fog
4. Cool fog + stratus
(-3oC)
5. Supercooled water
stratus (-13oC)
6. Highly supercooled
water stratus (-18oC)
7. Cb with lightning
8. Thick cirrus
9. Thin cirrus
Recommended RGB for Monitoring of Night-time Fog
Version 1.0, 14 May 2004
Slide: 90
Day-time Fog over the Po Valley
20 November 2003
Version 1.0, 14 May 2004
Slide: 91
MSG-1, 20 November 2003, 11:00 UTC, HRV Channel
Version 1.0, 14 May 2004
Slide: 92
MSG-1, 20 November 2003
Difference IR3.9 - IR10.8
Night
Fog darker than
clear ground
Dawn
Fog and clear
ground equal
Day
Fog brighter than
clear ground
1 to 2 critical slots at dawn/dusk
Version 1.0, 14 May 2004
Slide: 93
Click on the icon to
see the animation
(00:00-15:00 UTC,
AVI, 15068 KB) !
MSG-1, 20 November 2003, 00:00 UTC, IR3.9 - IR10.8
Version 1.0, 14 May 2004
Slide: 94
SUMMARY
Version 1.0, 14 May 2004
Slide: 95
Detection of Fog/Low Stratus during
Daytime
• VIS0.6 and HRVIS: to disciminate between fog and
ground (fog white, ground dark)
• VIS0.8: less useful because of less contrast to
vegetated areas
• NIR1.6 and IR3.9: to discriminate between fog and
snow (fog high reflectivity, snow low reflectivity)
• IR3.9 - IR10.8: fog large positive values; clear
ground around 0 K (-5 K to +5 K)
Version 1.0, 14 May 2004
Slide: 96
Detection of Fog/Low Stratus during
Daytime
• RGB 03-02-01: fog white-pinkish; clear ground
greenish or reddish (depending in vegetation)
• RGB 03-12-12: fog white-pinkish; clear ground
reddish
• RGB 02-04r-09: fog white-pinkish; clear ground
blueish
• RGB 02-03-04r: fog whitish, clear ground greenishbluish
Version 1.0, 14 May 2004
Slide: 97
Detection of Fog/Low Stratus during
Nighttime (Low and Mid Latitudes)
• IR3.9-IR10.8: fog -10/-7 K; clear ground around -4 K
(difficulties at high latitudes)
• RGB 10-09 / 09-04 / 09: fog light greenish-yellowish;
clear ground dark pinkish
Version 1.0, 14 May 2004
Slide: 98
Detection of Fog/Low Stratus during
Nighttime (High Latitudes)
• IR8.7-IR10.8: fog -4 K, clear ground around -1/-2 K
• RGB 10-09 / 09-07 / 09: fog light greenish-yellowish;
clear ground dark pinkish
Version 1.0, 14 May 2004
Slide: 99
Detection of Fog/Low Stratus at
Dawn/Dusk
• IR3.9-IR10.8: fog detection difficult because of
compensating effects (fog colder in IR3.9 than in
IR10.8 because of lower emissivity, but reflection of
solar radiation)
• IR8.7-IR10.8: fog -4 K, clear ground around -1/-2 K
(only small difference between fog and clear ground,
but works also at dawn/dusk)
Version 1.0, 14 May 2004
Slide: 100
Detection of Fog/Low Stratus: Conclusion
In operational applications, the difference IR8.7-IR10.8
may be the best to detect fog/low stratus (day- and night),
because of:
• Less noisy than the difference IR3.9 - IR10.8
(works well also over Scandinavia)
• 24-hour capability with "constant" colour for fog/low
stratus (unlike IR3.9-IR10.8 difference)
• High-level Cirrus above fog/low stratus can also be
detected (combined with IR12.0-IR10.8 difference)
Version 1.0, 14 May 2004
Slide: 101
MSG-1, 9 November 2003, 00:15 UTC, Difference Image, IR8.7 - IR10.8
Click on the icon to see the animation (00:15-08:15 UTC, AVI, 10550 KB) !
Version 1.0, 14 May 2004
Slide: 102