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Jochen Kerkmann Satellite Meteorologist, Training Officer jochen.kerkmann@eumetsat.int Contributors: G. Bridge (EUM), C. Georgiev (Bulgaria) P. Chadwick (Canada). APPLICATIONS OF METEOSAT SECOND GENERATION (Meteosat-8) AIRMASS RGB. Objectives.
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Jochen Kerkmann Satellite Meteorologist, Training Officer jochen.kerkmann@eumetsat.int Contributors: G. Bridge (EUM), C. Georgiev (Bulgaria) P. Chadwick (Canada) APPLICATIONS OFMETEOSAT SECOND GENERATION (Meteosat-8)AIRMASS RGB
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.
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
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
Airmass RGB Example combines the best three MSG features for the early detection of rapid cyclogenesis ! MSG-1, 07 January 2005, 03:00 UTC, RGB Composite WV6.2-WV7.3, IR9.7-IR10.8, WV6.2
Airmass RGB: Colour Inputs Red = WV6.2 - WV7.3 Green = IR9.7 - IR10.8 Blue = WV6.2i RGB
Airmass RGB: Colour Inputs Red = WV6.2 - WV7.3 Green = IR9.7 - IR10.8 Blue = WV6.2i RGB
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
Channel 05 (WV6.2) MSG-1, 07 January 2005, 03:00 UTC, Channel 05 (WV6.2) Range: 253 K (black) to 213 K (white)
Channel 06 (WV7.3) MSG-1, 07 January 2005, 03:00 UTC, Channel 06 (WV7.3) Range: 273 K (black) to 213 K (white)
BTD WV6.2 - WV7.3 MSG-1, 07 January 2005, 03:00 UTC, Difference WV6.2 - WV7.3 Range: -35 K (black) to 0 K (white)
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
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
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)
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)
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)
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)
Crossover Effect (Weldon & Holmes, 1991) 6.2 m 6.2 m 6.2 m
BTD WV6.2 - WV7.3 MSG-1, 07 January 2005, 03:00 UTC, Difference WV6.2 - WV7.3 Range: -30 K (black) to +5 K (white)
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
Channel 08 (IR9.7) MSG-1, 07 January 2005, 03:00 UTC, Channel 08 (IR9.7 (ozone channel)) Range: 263 K (black) to 213 K (white)
Channel 09 (IR10.8) MSG-1, 07 January 2005, 03:00 UTC, Channel 09 (IR10.8) Range: 293 K (black) to 213 K (white)
BTD IR9.7 - IR10.8 MSG-1, 07 January 2005, 03:00 UTC, Difference IR9.7 - IR10.8 Range: -50 K (black) to 0 K (white)
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. satellite 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 %) ==> strong diurnal/seasonal cycle due to T(surf) variation *neglecting WV absorption
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. Satellite 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) > T(ozone) *neglecting WV absorption
BTD IR9.7 - IR10.8 9.7 m 10.8 m T(ozone) T(surf/cloud) (surf/cloud)9.7 (surf/cloud)10.8
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)
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)
BTD IR9.7 - IR10.8: Effect of T(surf) 23 June 2004, 12:00 UTC 07 January 2005, 12:00 UTC Difference IR9.7 - IR10.8 Range: -45 K (black) to +5 K (white)
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
BTD IR9.7-IR10.8: Effect of Ozone Source: MeteoSwiss Annual cycle of the total ozoneamount above Arosa (CH)
BTD IR9.7-IR10.8: Effect of Ozone Source: MeteoSwiss
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, 11:30 UTC Difference IR9.7 - IR10.8
Blue Colour Beam: WV6.2 Recommended Range and Enhancement: Beam Channel Range Gamma Blue WV6.2 +243 … +208 K 1.0
Channel 05 (WV6.2) MSG-1, 07 January 2005, 03:00 UTC, Channel 05 (WV6.2) Range: 253 K (black) to 213 K (white)
Interpretation of WV Images Source: Weldon & Holmes, 1991 Bright. Temp. Layer-top Temp. Layer of an atmosphere opaque to the radiation
Features seen in WV Images United Kingdom Dry intrusion France Met-7, 26 December 1999, 06:00 UTC, WV Channel (Storm "Lothar") Source: DWD
Features seen in WV Images Convex Deformation Zone Saddle Point X N X N GOES-12, 14 February 2004, 00:15 UTC, WV Channel Source: NOAA & P. Chadwick
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, 12:15 UTC, Channel 05 (WV6.2)
Features seen in WV Images Algeria Mali High-level gravity waves caused by thunderstorms MSG-1, 25 June 2005, 14:15 UTC, Channel 05 (WV6.2)
Airmass RGB: Colour Interpretation 3 4 2 1 4 3 2 1 3 2 4 1 1 = high clouds (white) 2 = mid-level clouds (light ochre) 3 = rich ozone tropical airmass with high tropopause (greenish) 4 = low ozone polar airmass with low tropopause (bluish) -25 K WV6.2 - WV7.3 0 K -40 K IR9.7 - IR10.8 +5 K 243 K WV6.2 208 K
Airmass RGB Example: Warm Airmass MSG-1, 7 January 2005, 22:00 UTC
Airmass RGB Example: Warm Airmass 05 - 06 08 - 09 05i In RGB 05-06,08-09,05i images, warm airmasses with high tropopause appear in greenish colours ! The values shown above (in the red box) correspond tothe location (shown by an arrow) on the previous slide !
Airmass RGB Example: Cold Airmass MSG-1, 7 January 2005, 22:00 UTC
Airmass RGB Example: Cold Airmass 05 - 06 08 - 09 05i In RGB 05-06,08-09,05i images, cold airmasses with low tropopause appear in bluish colours ! The values shown above (in the red box) correspond tothe location (shown by an arrow) on the previous slide !
Airmass RGB Example: Advection Jet MSG-1, 7 January 2005, 22:00 UTC