introduction into the absorption channels

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Introduction into the Absorption Channels

Description of characteristics and content of the CO2 channel:

Ch11: 13.4

Contact person:Veronika Zwatz-Meisezwatz-meise@zamg.ac.atVersion 1.0. 13 July 2004

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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)

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„CO2 channel“

Ch11: 13.4 m

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Sun radiation Earth radiation

Ch11: 13.4

Wavelength (micron)

Watt/m2 andmicron

Ozone

Carbondioxid

Watervapour

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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

only VIS

VIS +IR

only IR

• 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 radiationWatt/m2

andmicron

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• Ch11 is in the wing of the CO2 absorption band around 15 m

EnergyspectrumSource:EUMETSAT

Ch11

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Maximal signal from around 870 hPaWeighting

functionsSource:EUMETSAT

8Figure 3d

Maximal signal from around 820 hPaWeightingfunctionsSource:EUMETSAT

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Application areas for the CO2 channel

• Qualitative application of images:– No additional features compared to the IR window

channels

– No special application for qualitative image interpretation (at the time being)

• Quantitative applications:– temperature profiles

– instability

– winds

10Ch11:13.4

11Ch09:10.8

12Ch10:12.0