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

Multispectral data in distinguishing ice & water clouds

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 COMPOSITES FOR 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  m. Green:Cloud particle size and phase, approximated by the 1.6  m or 3.9  m solar reflectance component. Blue:Temperature, provided by the 10.8  m 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  m, 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 stagewhitewhitewhitelight grey (low, warm water cloud)opt thickwaterwaterwarm II. First convection*whitewhitewhitedark grey (first convective towers)opt thicksupercooledsupercooledcoldwater III. First icingwhitelight greygreyblack (transformation in Cb)opt thicksmall icesmall icevery cold IV. Large icingwhitedark greyblackblack (Cb anvils)opt thicklarge icelarge icevery cold *This phase is more frequent in Africa, i.e. it is more easy to find examples for this phase in tropical convection

RedGreenBlue VIS0.6IR3.9IR10.8RGB I. Very early stage white-light yellow II. First convection yellow III. First icing orange IV. Large icing25500red RGB

RGB 0.6 / 3.9 / 10.8 I. Very early stagewhite-light yellow II. First convectionyellow III. First icingorange IV. Large icingred I II III IV RGB

RedGreenBlue VIS0.6NIR1.6IR10.8RGB I. Very early stage white-light yellow II. First convection yellow III. First icing orange IV. Large icing red-orange RGB

II. First Convection (Supercooled Clouds) MSG-1, 5 June 2003, 10:00 UTC, RGB Supercooled Water Clouds

III. First Icing MSG-1, 5 June 2003, 10:30 UTC, RGB Cb Icing

IV. Large Icing MSG-1, 5 June 2003, 11:30 UTC, RGB Large Ice Small Ice

V. Very Large Icing MSG-1, 5 June 2003, 13:30 UTC, RGB Large Ice

PART 2: CHANNEL DIFFERENCES USEFUL TO MONITOR CONVECTION NIGHT-TIME

Recommended Differences IR3.9 - IR10.8particle size, phase IR8.7 - IR10.8optical thickness IR IR10.8optical thickness WV6.2 - IR10.8overshooting tops WV6.2 - WV7.3overshooting tops

PART 3: RECOMMENDED RED-GREEN-BLUE (RGB) COLOUR COMPOSITES FOR MONITORING CONVECTION NIGHT-TIME

Recommended RGBs Night-time Red:Cloud optical depth, approximated by the  m or brightness temperature. Green:Cloud particle size and phase, approximated by the  m brightness temperature. Blue:Temperature, provided by 10.8  m brightness temperature.

Typical Convective Development - Nighttime I. Very early stagewhitewhitewhitelight grey (low, warm water cloud)opt thickopt thicklow waterwarm II. First convection*whitewhitelight greydark grey (first convective towers)opt thicksupercooledsupercooledcoldwater III. First icingwhitegreyb/w noiseblack (transformation in Cb)opt thickice cloudvery coldvery cold IV. Large icingwhitegreyb/w noiseblack (Cb anvils)opt thickice cloudvery coldvery cold *This phase is more frequent in Africa, i.e. it is more easy to find examples for this phase in tropical convection

RedGreenBlue RGB I. Very early stage white-light yellow II. First convection light brown III. First icing255100/2550red-yellow IV. Large icing255100/2550red-yellow RGB / / 09

summary day RGB for deep convection during day time – Day RGB149 or RGB139 Deep Convection 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