Recent developments in near-Recent developments in near-infrared retrievals of CHinfrared retrievals of CH44 and CO and CO

Christian Frankenberg, Annemieke Gloudemans, Jos de Christian Frankenberg, Annemieke Gloudemans, Jos de Laat, Hans SchrijverLaat, Hans Schrijver

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CHCH44 from channel 6 from channel 6

• New methane spectroscopic parameters in the NIR availableNew methane spectroscopic parameters in the NIR available

• Atmospheric water vapour detected to be a crucial error sourceAtmospheric water vapour detected to be a crucial error source

Seasonal bias over Australia resolvedSeasonal bias over Australia resolved

• Tropical enhancements not as high as previous inversions Tropical enhancements not as high as previous inversions suggestedsuggested

• Inversions still point at underestimated tropical sources but are Inversions still point at underestimated tropical sources but are more consistent with the ground-based networkmore consistent with the ground-based network

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Methane spectroscopy, the 2Methane spectroscopy, the 2νν33 band band

Frankenberg et al, submitted to ACPD

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Multi-spectra fit, results for the Q-BranchMulti-spectra fit, results for the Q-Branch

Frankenberg et al, submitted to ACPD

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High resolution FTIR retrievals as a test-bedHigh resolution FTIR retrievals as a test-bed

Frankenberg et al, submitted to ACPD

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Atmospheric water vaporAtmospheric water vaporImplication on SCIA CHImplication on SCIA CH44 retrievals retrievals

Frankenberg et al, submitted to GRL

About 20-40ppb differenceAbout 20-40ppb difference

Frankenberg et al, Science, 2005

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Implications on SCIAMACHY retrievalsImplications on SCIAMACHY retrievals

Frankenberg et al, submitted to ACPD

Seasonal bias of about 1%Seasonal bias of about 1%

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Atmospheric water vapourAtmospheric water vapourImplication on SCIA CHImplication on SCIA CH44 retrievals retrievals

Frankenberg et al, submitted to GRL

Optimised treatment of water absorptions

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CO retrievals (channel 8)CO retrievals (channel 8)

• Results from R branch (less interference from water lines)Results from R branch (less interference from water lines)

• Developments:Developments:• Results extended to 2006Results extended to 2006• 2007 will be started soon; many pixels die in that year!2007 will be started soon; many pixels die in that year!• Improvements in spectroscopy of water and methaneImprovements in spectroscopy of water and methane• Coming improved correction for scattering by ice layer (?)Coming improved correction for scattering by ice layer (?)

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Monthly averages April 2003 - 2006Monthly averages April 2003 - 2006

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Improvements in spectroscopy (line broadening)Improvements in spectroscopy (line broadening)

HITRAN Janouvrier et al 2007 (H2O), Predoi-Cross et al 2006 (CH4)

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Improvement in error statisticsImprovement in error statistics

Standard deviation SCIA – TM5for old (blue) and new (black) spectroscopy

Average difference (bias) SCIA – TM5 for old (blue) and new (black) spectroscopy