RedGreenBlue RGB Air Mass and Dust Products John Knaff 1 RedBlueGreen RGB Products Air Mass MSG Ch 5 625 µ m 6 735 µ m 8 966 µ m 9 108 µ m R WV625 WV735 25 to 0 K ID: 143763
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2011 NHC Proving Ground Products Red-Green-Blue (RGB) Air Mass and Dust Products John Knaff
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Red-Blue-Green (RGB) ProductsAir MassMSG
Ch 5 (6.25µm), 6 (7.35µ
m), 8 (9.66µm), 9 (10.8
µm)R = WV6.25 - WV7.35 (-25 to 0 K)G = IR9.66 - IR10.8 (-40 to +5 K)
B = WV6.25 (243 to 208 K)Detect the position of jet streams and areas of dry descending stratospheric air with high PV (red areas)
Discriminate tropical air masses (i.e., rich-ozone tropical air mass vs. low-ozone polar air mass)
Discriminates subtropical air masses (dryer subtropics vs. moister tropics)
Detect typical WV features like cold lows, deformation zones and wave features
Clouds heights can also be inferred by brightness
Dust/Microphysics
MSG Ch 7 (8.7µm), 8 (9.66µm), 9 (10.8µm), 10 (12.0µm)R = IR10.8 – IR12.0 (-2 to 4 K)G = IR10.8- IR8.7 (0 to +15 K, γ=2.5)B = IR10.8 (261 to 289 K)Dust appears as purple, pink or magentaGenerally thicker dust clouds appear as dark magenta or purpleLevel, thickness, and phase (ice/water) can be inferred.Animation helps to confirm moving features
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RGB Airmass Product Interpretation of Colors
Thick, high-level clouds
Thick, mid-level clouds
Thick, low-level clouds
(warm airmass)
Thick, low-level clouds
(cold airmass)
Jet (high PV) Cold Airmass Warm Airmass Warm Airmass
Deeper Moisture
Shallower Moisture
Copyright EUMETSAT
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Dust Microphysics:Interpretation
of Colors
for Low/Mid-level Clouds
Ocean Warm Desert Cold Desert Warm Land Cold Land
Thick, mid-level cloud
Thin, mid-level cloud
Low-level cloud
(cold atmosphere, Europe)
Low-level cloud
(
warm atmosphere
, Africa)
Dust Storm
Night
day
Copyright EUMETSAT
Day
Cold, thick, high-level clouds
Thin
cirrus
clouds /
contrails
over vegetated
land/ocean
over sand desert
Ocean Warm Desert Cold Desert Warm Land Cold Land
Dust Microphysics: Interpretation
of Colors for High-level Clouds
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Limb effects
Warm moist
Warm dryer
Cooler
airmassHot Dry
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DUST – hot background
Low clouds
Over
ocean
High cloud
Mid-level clouds
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