Institute for Environmental Physics and Remote Sensing (IUP/ife) Physics/Electrical Engineering 1 K.-U. Eichmann, C. von Savigny, G. Rohen, J. Kaiser,

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Institute for Environmental Physics and Remote Sensing (IUP/ife) Physics/Electrical Engineering

K.-U. Eichmann, C. von Savigny, G. Rohen, J. Kaiser, H. Bovensmann, J.P. Burrows

First retrieval of NIR CH4 profiles from SCIAMACHY measurements?

Institute of Environmental PhysicsUniversity of Bremen

Germany

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• vertical resolution: 2.6 km• horizontal resolution in

azimuth direction: 240 km (120 km min.)

• horizontal resolution in flight direction: approx. 400 km

• Duration of Limb sequence: 60 sec.

SCIAMACHY Limb Measurements

Limb view for SOLSE/LORE instruments

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Requirements UV-VIS-SWIR RTM Limb

SCIATRAN/CDIPI

(A. Rozanov 2001)

SCIARAYs

(Kaiser 2001)

Refraction

Full Sphericity

Multiple Scattering (double scattering)

Ground Reflection

Rayleigh, Mie-Scattering

Analytical Weighting Functions

(In progress)

Computational fast for global analysis of data

Occultation included

Modelling the Radiative Transfer

SCIARAYS: LBL mode, SFC included

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Optimal Estimation

x0: ln of the a priori O3 profile xn: ln of the nth estimatey: ln of the measured Chappuis-Triplettsyn: ln of the modelled Chappuis-Tripletts for xn

Sx: covariance matrix of the a priori S: covariance matrix of yK: Weighting function matrix

n3

mcmn zOln

THlnyK

yn and K will be determined by the radiative transfer model SCIARAYS [Kaiser, 2001]

xn+1 = x0 + SxKnT[KnSxKn

T + S] -1 (y - yn - Kn(x0-xn))

S = Sx - SxKT[KSxKT + S]-1 KSx

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Rozanov: Differential retrieval employing O3 Huggins and Chappuis bandsSavigny: 3 wavelength retrieval employing O3 Chappuis bands

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20

30

40

50

0 1x1012 2x1012 3x1012 4x1012 5x1012 6x1012 7x1012

10 - 40 km O3 columns:

SCIAMACHY: 378 DUPOAM III: 384 DU

Total O3 column:

GOME: 459 DUTOMS: 456 DU

SCIAMACHY - POAM III coincidence on April 25, 2002

SCIA, Rozanov Lat: 56o-59o N, Long: 238o-253o, 18:30 UTC

SCIA, Savigny Lat: 56o-59o N, Long: 238o-253o, 18:30 UTC

POAM, Lat: 62o N, Long: 253o, 2:50 UTC

O3 density [cm -3]

Altitu

de

[km

]

Is SCIARAYS good enough?

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CH4 x-section

Ch. 6 (1000-1750 nm, 1.5 nm)

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CH4 x-section channel 8

Ch. 8 (2265-2380 nm, 0.26 nm)

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Convoluted x-section of CH4

Hitran 2000 database

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VMR profiles of NIR absorbers

Profiles from ACE study

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Radiance at 6 km Tangent height

CH4 (using SCIARAYS in LBL mode)

CH4 (after slit function convolution)

Red: H2OBlue: CO2

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Radiance without CO2 and H2O

Dotted Line: without CO2 and H2O

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High resolution

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Modelled Radiances after SFCTangent heightsevery 3 km between3 and 30 km (from top to bottom), Using SCIARAYS as a RTM.

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Smoothed WF

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WF @ 1666 nm

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Different THs @ Channel 6

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SCIAMACHY Level 1 measurementsat 10 and 16 km

TH = 10 km(twilight measurements)

TH = 10 km(daytime measurements)

TH = 16 km(daytime)

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SCIAMACHY Level 1 measurementsat 10 and 16 km

TH = 10 km(twilight measurements)

TH = 10 km(daytime measurements)

TH = 16 km(daytime)

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SCIA L1: 20 and 26 km

With dead/bad pixels

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Without dead/bad pixel

20 km

26 km

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SCIAMACHY Channel 6: TH=65.8 km

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One state (Ch. 6) at 85 km

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Mesospheric OH emission lines

Black:Night

Red:Twilight

Blue:Day

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Conclusions

• NIR retrieval chain is not ready yet, but will be in the next few weeks.

• If it is possible to retrieve CH4 from Channel 6 (or Channel 8) from Limb measurements is still an open question.

• OH (both night and day emissions) seems to be a good candidate for further studies.

Documents

Institute for Environmental Physics and Remote Sensing (IUP/ife) Physics/Electrical Engineering 1 K.-U. Eichmann, C. von Savigny, G. Rohen, J. Kaiser,