SCIAMACHY Validation Workshop, 6-8 Dec 2004, Bremen

CO, CH4, CO2, and N2O columns retrieved from SCIAMACHY by WFM-DOAS: Algorithm, released data products, and initial

validation/verification

M. Buchwitz, R. de Beek, H. Bovensmann, J. P. Burrows (IUP/IFE-Bremen)

Data products released for validation

WFM-DOAS data products: Vertical columns of CO, CH4, CO2, and N2O; Dry air column averaged mixing ratios (O2 normalized columns) XCH4, XCO2, and XN2O

WFM-DOAS Version 0.4 finished in March 2004; processing of first large data set (~30 days of 2003); availability of first products announced on 17 March 2004

Initial validation results presented at 2nd ENVISAT Validation Workshop ACVE-2, May 2004, Frascati, ESA/ESRIN

-> Details see references on next slide

Processing of all consolidated orbits available for the year 2003; availability announced on 6 September 2004 (v0.4)

Improved methane (v0.41) announced on 30 September 2004

Analysis ongoing ...

Recent publications

Atmospheric Chemistry and Physics (ACP/ACPD):Buchwitz, M., R. de Beek, K. Bramstedt, S. Noël, H. Bovensmann, and J. P. Burrows, Global carbon monoxide as retrieved from SCIAMACHY by WFM-DOAS, ACP, 4, 1945-1960, 2004

Buchwitz, M., R. de Beek, J. P. Burrows, H. Bovensmann, T. Warneke, J. Notholt, J. F. Meirink, A. P. H. Goede, P. Bergamaschi, S. Körner, M. Heimann, J.-F. Muller, and A. Schulz, Atmospheric methane and carbon dioxide from SCIAMACHY satellite data: Initial comparison with chemistry and transport models , ACPD, 2004

Warneke, T., de Beek, R., Buchwitz, M., et al., O., Shipborne solar absorption measurements of CO2, CH4, N2O, and CO and comparison the SCIAMACHY WFM-DOAS retrievals, ACPD (submitted), 2004

Sussmann, R., and Buchwitz, M., Validation of ENVISAT/SCIAMACHY columnar CO by FTIR profile retrievals at the ground truthing station Zugspitze, ACPD (submitted), 2004

ENVISAT validation workshop ACVE-2 (May 2004, Frascati):de Maziere, M., Barret, B., Blumenstock, T., Buchwitz, M., de Beek, R., et al., Comparison between SCIAMACHY scientific products and ground-based FTIR data for total columns of CO, CH4, and N2O, proceedings ACVE-2 (ESA Special

Publication), ESA/ESRIN, Frascati, Italy, 3-7 May 2004, 2004

Gloudemans, A. M. S., Schrijver, H., Straume, A. G., Aben, I., Maurellis, A. N., Buchwitz, M., de Beek, R., et al., CH4 and CO

total columns from SCIAMACHY: Comparisons with TM3 and MOPITT, proceedings ACVE-2 (ESA Special Publication), ESA/ESRIN, Frascati, Italy, 3-7 May 2004, 2004

ENVISAT Symposium (Sept. 2004, Salzburg):Buchwitz, M., R. de Beek, S. Noël, H. Bovensmann, and J. P. Burrows, Retrieval of CO, H2O, CH4, CO2, ans N2O columns

from SCIAMACHY/ENVISAT by WFM-DOAS: Current status, ESA Special Publication SP-572, 2004.

WFM-DOAS algorithm

SCIAMACHY nadir spectrum & fitting windows

CH4, N2O CO

O2 CO2

Carbon monoxide from SCIAMACHY

Carbon monoxide (CO)

CO: Single overpass

Mozambique:

CO plumes from fires

Fires due to biomass burning in Africa Oct 2003

Buchwitz et al., ACP, 2004

CO: Single overpass II

Buchwitz et al., ACP, 2004

CO averaging kernels: SCIAMACHY and MOPITT

Emmons et al., JGR, 2004

MOPITTSCIAMACHY

Buchwitz et al., ACP, 2004

CO: Seasonal averages

CO: Monthly means compared with MOPITT

MOPITT data: H. Bremer, IUP-Bremen

CO: Monthly means compared with MOPITT II

ATSR Fire Atlas

Fires Portugal Aug 2003

MOPITT data: H. Bremer, IUP-Bremen

Methane from SCIAMACHY

Methane (CH4)

Methane v0.4: Comparison with models

Day 2003

IHD SCIA

[ppbv]

IHD model

[ppbv]

Mean difference

SCIA – model

[ppbv]

Standard

Deviation

[ppbv]

Jan 24 53 56 +10 (+0.6%) 97 (5.6%)

Mar 28 30 48 -186 (-10.6%) 89 (5.1%)

May 30 110 56 +48 (+2.7%) 200 (11.3%)

Jul 23 31 63 -266 (-15.1%) 122 (6.8%)

TM5 data: P. Bergamaschi, JRC, Ispra

Methane v0.4: Bias analysis/correction

Gives daily

correction factor

based on SOST

throughput

analysis

Methane v0.41

1st order bias corrected XCH4 monthly averages:

v0.4: XCH4=CH4col/(O2col/0.2095) v0.41: XCH4=XCH4v0.4/(XCO2v0.4/370)

Normalization by CO2, see also results from C. Frankenberg, IUP/Heidelberg

Error source CH4 column O2 column CO2 column CH4/O2 CH4/CO2

Aerosol(OD 0.0) -0,3 -2,5 -0,8 2,2 0,5Subvisual cirrus(OD 0.03) -3,7 2,8 -1,4 -6,5 -2,3

Albedo(0.3 instead of 0.1) 0,8 -3,0 1,4 3,8 -0,6

WFM-DOAS v0.4 retrieval

errors (in percent)

Buchwitz and Burrows,

SPIE, 2004

Methane v0.41: Comparison with KNMI/TM3 model

7%

Methane v0.41: Comparison with JRC/TM5 model

Courtesy: P. Bergamaschi, JRC, Ispra

Correlation SCIA/WFMD CH4 v0.41 with JRC/TM5

Bias [ppbv]

0%

~5%

Carbon dioxide from SCIAMACHY

Carbon dioxide (CO2)

CO2 v0.4: Comparison with TM3/MPI-BGC model

Buchwitz et al., ACPD, 2004 TM3 data: S. Körner, MPI-BGC, Jena

CO2 v0.4: Comparison with TM3 /MPI-BGC model II

Buchwitz et al., ACPD, 2004 TM3 data: S. Körner, MPI-BGC, Jena

CO2 v0.4: Comparison with TM3 /MPI-BGC model III

XCO2-offset MPI-Jena

8 ppm

25 ppm (7%)May 03

Jul 03

Sep 03

Summary

Horizontal

resolution

[km x km]

Estimated

Precision

(scatter)

Estimated

Accuracy

(bias)

CO 30 x 120 10 - 20% 10 - 30%

CH4 30 x 120 1- 6% 2 - 15%

(v0.41: <5%)

CO2 30 x 60 1 - 4% 2 - 5%

N2O 30 x 120 10 – 20% 30%

Preliminary precision and accuracy estimates *)

WFM-DOAS Version 0.4 column retrieval

*) Status ACVE-2 (May 2004)

For measurements over land; based on a limited number of data (several days of the year 2003)

Details see: Buchwitz et al., Envisat Sym., 2004, and references given therein

Acknowledgements

This work has been funded by:

• BMBF via GSF and DLR-Bonn,

• the European Commission (5th Framework project EVERGREEN)

• and the State and the University of Bremen