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APPLICATIONS OF AIRMASS RGB

APPLICATIONS OF AIRMASS RGB. Objectives. Learn how to generate the Airmass RGB (Recipe) Learn how to use/interpret the WV6.2 - WV7.3 and the IR9.7 - IR10.8 brightness temperature difference (BTD)

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APPLICATIONS OF AIRMASS RGB

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  1. APPLICATIONS OFAIRMASS 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. 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

  4. 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

  5. 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

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

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

  8. 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

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

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

  11. 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)

  12. 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

  13. 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

  14. 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)

  15. 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)

  16. 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)

  17. 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)

  18. 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)

  19. 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

  20. 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)

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

  22. 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)

  23. 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

  24. 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

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

  26. 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)

  27. 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)

  28. 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)

  29. 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

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

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

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

  33. 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

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

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

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

  37. 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

  38. 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)

  39. 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)

  40. 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) 5 -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 ofdry air with a tropopause folding

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

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

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

  44. Airmass RGB: Interpretation of Colours Jet (high PV) Cold Airmass Warm Airmass Warm Airmass Thick, high-level clouds Thick, mid-level clouds Thick, low-level clouds (warm airmass) Thick, low-level clouds (cold airmass) High UTH Low UTH

  45. 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 5 MSG-1 07 January 2005 15:00 UTC RGB Composite R = WV6.2 - WV7.3 G = IR9.7 - IR10.8 B = WV6.2 4 3

  46. 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 12:00 UTC RGB Composite R = WV6.2 - WV7.3 G = IR9.7 - IR10.8 B = WV6.2 4 2 2

  47. 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 10:00 UTC

  48. Comparison Airmass RGB vs PV 300 hPa MSG-1, 8 January 2005, 06:00 UTC

  49. Comparison Airmass RGB vs TOZ MSG-1, 8 January 2005, 06:00 UTC

  50. Comparison Airmass RGB vs PV/TOZ MSG-1, 08 January 2005, 06:00 UTC PV 300 hPa Total Ozone

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