APPLICATIONS OF METEOSAT SECOND GENERATION Meteosat8 AIRMASS RGB

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APPLICATIONS OFMETEOSAT SECOND GENERATION
(Meteosat-8) AIRMASS RGB

• Jochen Kerkmann
• Satellite Meteorologist, Training Officer
• jochen.kerkmann_at_eumetsat.int
• Contributors G. Bridge (EUM), C. Georgiev
  (Bulgaria)
• P. Chadwick (Canada)

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Objectives

• Learn how to generate the Airmass RGB (Recipe)
• Learn how to use/interpret the WV6.2 - WV7.3 and
  theIR9.7 - IR10.8 brightness temperature
  difference (BTD)
• In particular, understand the relationship
  between the IR9.7 - IR10.8 BTD and the total
  ozone content
• Short overview of WV image interpretation
• Interpretation of colours of the Airmass RGB
• Usage of the Airmass RGB composite for monitoring
  jet streams, cyclogenesis, PV maxima etc.

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THE "AIRMASS" RGB
R Difference WV6.2 - WV7.3 G Difference IR9.7
- IR10.8 B Channel WV6.2
Applications Rapid Cyclogenesis, Jet Stream
Analysis, PV Analysis Area Full MSG Viewing
Area Time Day and Night
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Airmass RGB Recipe
Recommended Range and Enhancement Beam Channel
Range Gamma Red WV6.2 - WV7.3 -25 0
K 1.0 Green IR9.7 - IR10.8 -40 5
K 1.0 Blue WV6.2 243 208 K 1.0
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Airmass RGB Example
combines the best three MSG features for the
early detection of rapid cyclogenesis !
MSG-1, 07 January 2005, 0300 UTC, RGB
Composite WV6.2-WV7.3, IR9.7-IR10.8, WV6.2
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Airmass RGB Colour Inputs
Red WV6.2 - WV7.3 Green
IR9.7 - IR10.8
Blue WV6.2i
RGB
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Airmass RGB Colour Inputs
Red WV6.2 - WV7.3 Green
IR9.7 - IR10.8
Blue WV6.2i
RGB
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Red Colour Beam WV6.2 - WV7.3
Recommended Range and Enhancement Beam Channel
Range Gamma Red WV6.2 - WV7.3 -25 0
K 1.0
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Channel 05 (WV6.2)
MSG-1, 07 January 2005, 0300 UTC, Channel 05
(WV6.2) Range 253 K (black) to 213 K (white)
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Channel 06 (WV7.3)
MSG-1, 07 January 2005, 0300 UTC, Channel 06
(WV7.3) Range 273 K (black) to 213 K (white)
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BTD WV6.2 - WV7.3
MSG-1, 07 January 2005, 0300 UTC, Difference
WV6.2 - WV7.3 Range -35 K (black) to 0 K (white)
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BTD WV6.2 - WV7.3
For cloud-free scenes, the BTD between WV6.2 and
WV7.3 depends on (in order of priority)
I. temperature and humidity profile II. satellite
viewing angle
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BTD WV6.2 - WV7.3
For cloudy scenes, the BTD between WV6.2 and
WV7.3 depends on (in order of priority)
I. temperature and humidity profile (above the
cloud) II. satellite viewing angle III. emissivity
of cloud at WV6.2 and WV7.3
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BTD WV6.2 - WV7.3
Case I Very Dry Atmosphere very small BTD
0 -10 -20 -25
6.2 ?m
7.3 ?m
T(850 hPa)
Moist Layer opaque to the radiation at WV6.2 and
WV7.3(Planetary Boundary Layer)
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BTD WV6.2 - WV7.3
Case II Moist Layer at 700 hPa small BTD
0 -10 -20 -25
6.2 ?m
7.3 ?m
T(700 hPa)
Moist Layer opaque to the radiation at WV6.2
less opaque to the radiation
at WV7.3
T(850 hPa)
Moist Layer opaque to the radiation at WV6.2 and
WV7.3(Planetary Boundary Layer)
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BTD WV6.2 - WV7.3
Case III Moist Layer at 500 hPa large BTD
0 -10 -20 -25
6.2 ?m
7.3 ?m
T(500 hPa)
Moist Layer quasi opaque to the radiation at
WV6.2 quite transparent to
the radiation at WV7.3
T(850 hPa)
Moist Layer opaque to the radiation at WV6.2 and
WV7.3(Planetary Boundary Layer)
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BTD WV6.2 - WV7.3
Case IV Moist Layer at 200 hPa small BTD
0 -10 -20 -25
6.2 ?m
7.3 ?m
T(200 hPa)
Moist Layer quite transparent to the radiation
at WV6.2 transparent to
the radiation at WV7.3
T(850 hPa)
Moist Layer opaque to the radiation at WV6.2 and
WV7.3(Planetary Boundary Layer)
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BTD WV6.2 - WV7.3
MSG-1, 07 January 2005, 0300 UTC, Difference
WV6.2 - WV7.3 Range -30 K (black) to 5 K (white)
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Green Colour Beam IR9.7 - IR10.8
Recommended Range and Enhancement Beam Channel
Range Gamma Green IR9.7 - IR10.8 -40 5
K 1.0
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Channel 08 (IR9.7)
MSG-1, 07 January 2005, 0300 UTC, Channel 08
(IR9.7 (ozone channel)) Range 263 K (black) to
213 K (white)
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Channel 09 (IR10.8)
MSG-1, 07 January 2005, 0300 UTC, Channel 09
(IR10.8) Range 293 K (black) to 213 K (white)
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BTD IR9.7 - IR10.8
MSG-1, 07 January 2005, 0300 UTC, Difference
IR9.7 - IR10.8 Range -50 K (black) to 0 K (white)
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BTD IR9.7 - IR10.8
For cloud-free scenes, the BTD between IR9.7 and
IR10.8 depends on (in order of priority)
I. temperature difference between T(surf) and
T(ozone) II. total ozone concentration III. satell
ite viewing angle IV. emissivity of surface at
IR9.7 and IR10.8(e.g. desert surface has a 3
difference in emissivity,water has a difference
of 0.3 )
gt strong diurnal/seasonal cycle due to T(surf)
variation
neglecting WV absorption
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BTD IR9.7 - IR10.8
For cloudy scenes, the BTD between IR9.7 and
IR10.8 depends on (in order of priority)
I. temperature difference between T(cloud) and
T(ozone) II. total ozone concentration III. Satell
ite viewing angle IV. emissivity of cloud at
IR9.7 and IR10.8
For high-level clouds T(cloud) ? T(ozone)For
mid/low-level clouds T(cloud) gt T(ozone)
neglecting WV absorption
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BTD IR9.7 - IR10.8
9.7 ?m
10.8 ?m
T(ozone)
T(surf/cloud)
?(surf/cloud)9.7
?(surf/cloud)10.8
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BTD IR9.7 - IR10.8
Case I Rich OzonePolar Airmass large BTD
5 -20 -40
9.7 ?m
10.8 ?m
T(ozone)
T(surf)
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BTD IR9.7 - IR10.8
Case II Low OzoneTropical Airmass smaller BTD
5 -20 -40
9.7 ?m
10.8 ?m
T(ozone)
T(surf)
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BTD IR9.7 - IR10.8 Effect of T(surf)
23 June 2004, 1200 UTC
07 January 2005, 1200 UTC
Difference IR9.7 - IR10.8 Range -45 K (black) to
5 K (white)
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BTD IR9.7-IR10.8 Effect of Ozone
260 DU ? -25 K 320 DU ? -33 K 400 DU ? -40
K Thumb rule BTD IR9.7-IR10.8 K -TOZ DU/10
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BTD IR9.7-IR10.8 Effect of Ozone
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BTD IR9.7-IR10.8 Effect of Ozone
Source MeteoSwiss
Annual cycle of the total ozoneamount above
Arosa (CH)
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BTD IR9.7-IR10.8 Effect of Ozone
Source MeteoSwiss
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BTD IR9.7-IR10.8 Effect of Viewing Angle
The larger the satellite viewing angle, the
stronger the ozone absorption effect(limb
cooling) !
MSG-1, 31 October 2003, 1130 UTC Difference
IR9.7 - IR10.8
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Blue Colour Beam WV6.2
Recommended Range and Enhancement Beam Channel
Range Gamma Blue WV6.2 243 208
K 1.0
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Channel 05 (WV6.2)
MSG-1, 07 January 2005, 0300 UTC, Channel 05
(WV6.2) Range 253 K (black) to 213 K (white)
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Features seen in WV Images
United Kingdom
Dry intrusion
France
Met-7, 26 December 1999, 0600 UTC, WV
Channel (Storm "Lothar")
Source DWD
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Features seen in WV Images
GOES-12, 14 February 2004, 0015 UTC, WV Channel
Source NOAA P. Chadwick
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Features seen in WV Images
Stau cloud
Foehn
Mountain waves in cloud-free areas with possible
Clear Air Turbulence (CAT)
Italy
MSG-1, 21 January 2005, 1215 UTC, Channel 05
(WV6.2)
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Features seen in WV Images
Algeria
Mali
High-level gravity waves caused by thunderstorms
MSG-1, 25 June 2005, 1415 UTC, Channel 05 (WV6.2)
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Airmass RGB Colour Interpretation
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-25 K WV6.2 -
WV7.3 0 K
5
-40 K IR9.7 -
IR10.8 5 K
5
243 K WV6.2
208 K
5 rich ozone airmass of dry air with a
tropopause folding
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Airmass RGB Example Warm Airmass
MSG-1, 7 January 2005, 2200 UTC
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Airmass RGB Example Cold Airmass
MSG-1, 7 January 2005, 2200 UTC
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Airmass RGB Example Advection Jet
MSG-1, 7 January 2005, 2200 UTC
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Airmass RGB Interpretation of Colours
Thick, high-level clouds
Thick, mid-level clouds
Thick, low-level clouds (warm airmass)
Thick, low-level clouds (cold airmass)
High UTH Low UTH
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Airmass RGB Colour Interpretation
1 high clouds 2 mid-level clouds 3 warm
airmass, high tropopause 4 cold airmass, low
tropopause 5 dry descending stratospheric air
2
1
MSG-1 07 January 2005 1500 UTC RGB Composite R
WV6.2 - WV7.3 G IR9.7 - IR10.8 B WV6.2
5
4
3
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Airmass RGB Colour Interpretation
1 high cloud (severe convective storm) 2
mid-level clouds 3 hot land surface
(high UTH) 4 hot land surface (low UTH)
1
3
MSG-1 21 August 2006 1200 UTC RGB Composite R
WV6.2 - WV7.3 G IR9.7 - IR10.8 B WV6.2
4
2
2
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Airmass RGB Global View
Note warm airmasses seen at a high satellite
viewing angle appear with a bluish colour (limb
cooling effect) !
MSG-1 19 April 2005 1000 UTC
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Comparison Airmass RGB vs PV 300 hPa
MSG-1, 8 January 2005, 0600 UTC
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Comparison Airmass RGB vs TOZ
MSG-1, 8 January 2005, 0600 UTC
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Comparison Airmass RGB vs PV/TOZ
MSG-1, 08 January 2005, 0600 UTC
PV 300 hPa
Total Ozone
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Comparison Airmass RGB vs PV/TOZ
MSG-1, 08 January 2005, 0600 UTC
PV 300 hPa
Total Ozone
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Comparison Airmass RGB vs PV 300 hPa
19 January 2005, 0615 UTC
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SUMMARY

• The "Airmass" RGB is a combination of 4 channels
  WV6.2, WV7.3, IR9.7 and IR10.8
• It helps to detect the position of jet streams
  and areas of dry descending stratospheric air
  with high PV (red areas)
• It also helps to discriminate airmasses (rich
  ozone tropical airmass, low ozone polar airmass)
• It is also useful to detect typical WV features
  like deformation zones and wave features
• At the same time, through the use of the IR
  channels, it allows to monitor cloud development
  at low, mid and high levels