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Basics Satellite Meteorology ( An Introduction to RS of MSG). Joseph Kagenyi Kenya Meteorological Department. Objective. Channel properties Signal source Discrimination of Ice / Water/ clouds Summary of channels applications. 12 channels data RGBs.
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Basics Satellite Meteorology(An Introduction to RS of MSG) Joseph Kagenyi Kenya Meteorological Department
Objective • Channel properties • Signal source • Discrimination of Ice / Water/ clouds • Summary of channels applications
12 channels data RGBs • Exploiting channel combinations to understand the observation products • Making multichannel approach relevant and applicable: • (MFG) 3 channels, • (MSG) 12 channels and • (MTG) 39 channels
PART 3: RECOMMENDED RED-GREEN-BLUE (RGB) COLOUR COMPOSITESFOR MONITORING CONVECTION DAY-TIME
Recommended RGBs Daytime Red: Cloud depth and amount of cloud water and ice, provided by the visible reflectance at 0.6 mm. Green: Cloud particle size and phase, approximated by the 1.6 mm or 3.9 mm solar reflectance component. Blue: Temperature, provided by the 10.8 mm channel.
Recommended RGBs Daytime - HRVIS Red: Cloud optical depth and detailed cloud top structures, provided by the HRVIS channel. Green: Cloud optical depth and detailed cloud top structures, provided by the HRVIS channel. Blue: Temperature, provided by 10.8 mm, or cloud particle size and phase, provided by the NIR1.6 or IR3.9 channel.
Typical Convective Development- Daytime - VIS0.6NIR1.6IR3.9IR10.8 I. Very early stage white whitewhite light grey (low, warm water cloud) opt thick waterwater warm II. First convection* white whitewhite dark grey (first convective towers) opt thick supercooledsupercooledcold waterwater III. First icing white light grey grey black (transformation in Cb) opt thick small icesmall ice very cold IV. Large icing white dark grey black black (Cb anvils) opt thick large icelarge ice very cold *This phase is more frequent in Africa, i.e. it is more easy to find examples for this phase in tropical convection
RGB 01-04-09 Red Green Blue VIS0.6IR3.9IR10.8RGB I. Very early stage 255 255 200 white-light yellow II. First convection 255255 100 yellow III. First icing 255 150 0 orange IV. Large icing 255 0 0red
RGB 01-04-09 RGB 0.6 / 3.9 / 10.8 I. Very early stage white-light yellow II. First convection yellow III. First icing orange IV. Large icing red II III I IV
RGB 01-03-09 Red Green Blue VIS0.6NIR1.6IR10.8RGB I. Very early stage 255 255 200 white-light yellow II. First convection 255 255 100 50 yellow III. First icing 255 200 0 orange IV. Large icing 255 100 0 red-orange
II. First Convection (Supercooled Clouds) Supercooled Water Clouds MSG-1, 5 June 2003, 10:00 UTC, RGB 01-03-09
III. First Icing Cb Icing MSG-1, 5 June 2003, 10:30 UTC, RGB 01-03-09
IV. Large Icing Large Ice Small Ice MSG-1, 5 June 2003, 11:30 UTC, RGB 01-03-09
V. Very Large Icing Large Ice MSG-1, 5 June 2003, 13:30 UTC, RGB 01-03-09
PART 2: CHANNEL DIFFERENCESUSEFUL TOMONITOR CONVECTION NIGHT-TIME
Recommended Differences IR3.9 - IR10.8 particle size, phase IR8.7 - IR10.8 optical thickness IR12.0 - IR10.8 optical thickness WV6.2 - IR10.8 overshooting tops WV6.2 - WV7.3 overshooting tops
PART 3: RECOMMENDED RED-GREEN-BLUE (RGB) COLOUR COMPOSITESFOR MONITORING CONVECTION NIGHT-TIME
Recommended RGBs Night-time Red: Cloud optical depth, approximated by the 12.0 - 10.8 mm or 10.8 - 8.7 brightness temperature. Green: Cloud particle size and phase, approximated by the 10.8 - 3.9 mm brightness temperature. Blue: Temperature, provided by 10.8 mm brightness temperature.
Typical Convective Development- Nighttime - 12.0-10.8 10.8-8.7 10.8-3.9 10.8 I. Very early stage white whitewhite light grey (low, warm water cloud) opt thick opt thick low water warm II. First convection* white white light grey dark grey (first convective towers) opt thick supercooledsupercooled cold waterwater III. First icing white grey b/w noise black (transformation in Cb) opt thick ice cloud very cold very cold IV. Large icing white grey b/w noise black (Cb anvils) opt thick ice cloud very cold very cold *This phase is more frequent in Africa, i.e. it is more easy to find examples for this phase in tropical convection
RGB 10-09 / 09-04 / 09 Red Green Blue 12.0-10.8 10.8-3.9 10.8 RGB I. Very early stage 255 255 200 white-light yellow II. First convection 255 200 100 light brown III. First icing 255 100/255 0 red-yellow IV. Large icing 255 100/255 0 red-yellow
summary • RGB for deep convection during day time • Day RGB149 or RGB139 • Deep Convection is also visible on - • Day Convection RGB(5-6,4-9,3-1) • At night Deep convection we use complex differencing: • Night Convection RGB (5-6,8-9, 9i) • Rgb10-9,9-4,9 • The Airmass RGB (5-6,8-9,5i) is also useful in extratropical regions