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APPLICATIONS OF METEOSAT SECOND GENERATION (Meteosat-8) AIRMASS RGB

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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APPLICATIONS OF METEOSAT SECOND GENERATION (Meteosat-8) AIRMASS RGB

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  1. 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

  2. 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.

  3. MSG SEVIRI Channels

  4. MSG SEVIRI IR Channels

  5. MSG Weighting Functions

  6. 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

  7. 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

  8. 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

  9. Airmass RGB: Colour Inputs Red = WV6.2 - WV7.3 Green = IR9.7 - IR10.8 Blue = WV6.2i RGB

  10. Airmass RGB: Colour Inputs Red = WV6.2 - WV7.3 Green = IR9.7 - IR10.8 Blue = WV6.2i RGB

  11. 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

  12. Channel 05 (WV6.2) MSG-1, 07 January 2005, 03:00 UTC, Channel 05 (WV6.2) Range: 253 K (black) to 213 K (white)

  13. Channel 06 (WV7.3) MSG-1, 07 January 2005, 03:00 UTC, Channel 06 (WV7.3) Range: 273 K (black) to 213 K (white)

  14. 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)

  15. 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

  16. 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

  17. 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)

  18. 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)

  19. 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)

  20. 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)

  21. Crossover Effect (Weldon & Holmes, 1991) 6.2 m 6.2 m 6.2 m

  22. 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)

  23. 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

  24. 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)

  25. Channel 09 (IR10.8) MSG-1, 07 January 2005, 03:00 UTC, Channel 09 (IR10.8) Range: 293 K (black) to 213 K (white)

  26. 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)

  27. 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

  28. 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

  29. BTD IR9.7 - IR10.8 9.7 m 10.8 m T(ozone) T(surf/cloud) (surf/cloud)9.7 (surf/cloud)10.8

  30. 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)

  31. 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)

  32. 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)

  33. 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

  34. BTD IR9.7-IR10.8: Effect of Ozone

  35. BTD IR9.7-IR10.8: Effect of Ozone Source: MeteoSwiss Annual cycle of the total ozoneamount above Arosa (CH)

  36. BTD IR9.7-IR10.8: Effect of Ozone Source: MeteoSwiss

  37. 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

  38. Blue Colour Beam: WV6.2 Recommended Range and Enhancement: Beam Channel Range Gamma Blue WV6.2 +243 … +208 K 1.0

  39. Channel 05 (WV6.2) MSG-1, 07 January 2005, 03:00 UTC, Channel 05 (WV6.2) Range: 253 K (black) to 213 K (white)

  40. Interpretation of WV Images Source: Weldon & Holmes, 1991 Bright. Temp. Layer-top Temp. Layer of an atmosphere opaque to the radiation

  41. Features seen in WV Images United Kingdom Dry intrusion France Met-7, 26 December 1999, 06:00 UTC, WV Channel (Storm "Lothar") Source: DWD

  42. 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

  43. 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)

  44. 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)

  45. 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

  46. Airmass RGB Example: Warm Airmass MSG-1, 7 January 2005, 22:00 UTC

  47. 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 !

  48. Airmass RGB Example: Cold Airmass MSG-1, 7 January 2005, 22:00 UTC

  49. 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 !

  50. Airmass RGB Example: Advection Jet MSG-1, 7 January 2005, 22:00 UTC

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