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Introduction into the Window Channels. Description of characteristics and content of the channels: Ch07: 8.7 Ch09: 10.8 Ch10: 12.0 . Contact person: Veronika Zwatz-Meise zwatz-meise@zamg.ac.at Version 1.0. 13 July 2004. All MSG channels. Channel 01: VIS 0.6
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Introduction into the Window Channels Description of characteristics and content of the channels:Ch07: 8.7 Ch09: 10.8 Ch10: 12.0 Contact person: Veronika Zwatz-Meise zwatz-meise@zamg.ac.at Version 1.0. 13 July 2004
All MSG channels • Channel 01: VIS 0.6 • Channel 02: VIS 0.8 • Channel 03: NIR 1.6 • Channel 04: MIR 3.9 • Channel 05 WV 6.2 • Channel 06: WV 7.3 • Channel 07: IR 8.7 • Channel 08: IR 9.7 („Ozon“) • Channel 09: IR 10.8 • Channel 10: IR 12.0 • Channel 11: IR 13.4 („CO2“) • Chanell 12: HRV (High Resolution Visible)
Ch07: 8.7 Ch09: 10.8 Ch10: 12.0 Sun radiation Earth radiation Watt/ m2 and micron Ozone Carbon dioxid Water vapour Wavelength (micron)
Comparison of radiation sources sun - earth • For wave length < 5 m solar radiation is dominant • For wave length > 5 m radiation of earth is dominant • Ch01, 02, 03, 12: only sun radiation • Ch04: both: radiation from sun and earth • Ch 05, 06, 07, 08, 09, 10, 11: only thermal earth radiation Sun radiation Earth radiation Watt/ m2 and micron only VIS VIS + IR only IR
Ch07, 09, 10 in window region Therefore: no fundamental attenuation of the radiation through absorption Energy spectrum Source:EUMETSAT Ch07 Ch09 Ch10
Max. signal in the window channels from the surface and lower part of troposphere Weighting functions Source:EUMETSAT Figure 3c
Application areas for the window channels • Recognition of cloud systems because of the thermal radiation of cloud and earth surface • Extraction of high thin Cirrus from the whole cloud systems
Some characteristica: Ch07: 8.7 • Indicative for high, thin Cirrus cloud • improved recognition of Cirrus • best use through preparation of RGBs and differences • Support for discrimination between ice- and water cloud • From optical point of view (at the time being) no typical new features recognisable
Ch09: 10.8 and Ch10: 12.0 These channels are comparable to the relevant NOAA channels
Some characteristica: Ch09: 10.8 and Ch10: 12.0 • Usual evaluation of cloud in both channels • Not much difference between the apperance in the three window channels • Ch10 is more sensitive for high thin Cirrus • not easy to recognise through checking by eyes • difference images give information
Split window Ch09: 10.8 and Ch10: 12.0 • Ch10 is more sensitive for high thin Cirrus • not easy to recognise through checking by eyes • difference images give information
Different Absorption of Ice- and Watercloud between 10.8 and 12.0 m Higher absorption in the ice phase in 12.0 Absorption of Ice- and Water cloud After Source: D. Rosenfeld
Examples for visualisation of high Cirrus Differencen of I07, I09, I10 Source: Jochen Kerkmann kerkmann@eumetsat.de
Difference I07 - I09 Angola
Difference I09 - I10 Angola
Difference I07 - I09 S-Atlantic
Difference I09 - I10 S-Atlantic