global satellite validation of sciamachy o 3 and n o 2 columns with gome wfdoas /3.0

Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1

Astrid Bracher, M. Weber, K. Bramstedt,M. Coldewey-Egbers, L. N. Lamsal, John Burrows

Institute of Environmental Physics (IUP/IFE), University of Bremen

(part of it to be submitted to ACP special issue in December 2004)

SCIAMACHY Validation Workshop, Bremen, Germany, 7 Dec 2003

Global satellite validation of SCIAMACHY O3

and NO2 columns with GOME WFDOAS/3.0

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SCIAMACHY total O3 validation with GOME WFDOAS

All SCIAMACHY 5.01/5.04 from Jan - June 2003 compared to GOME WFDOAS V1.0(to be submitted to ACP SCIAMACHY special issue II)

SCIAMACHY reprocessed data of 2003 mixture of v5.01/5.04:only differences in processing settings, wrong season index in 5.01 for Jan-Mar 2003

equivalent to GOME GDP 2.4:•no efficient temperature correction•AMF calculations: -with ozone climatology based on 2 dim CTM -no iterations to match tO3 a priori with meas.•limited treatment of atmos. profile shape effect •partly unsuitable spectral analysis when atmos-

phere becomes optically thick. UV fit window 325-335 nm

GOME GDP 2.4 known for:strong dependencies to sza, tO3, seasons, latitude

GOME WFDOAS by Coldewey-Egbers et al. (ACPD, 2004)

•Improved Raman correction ( to account for O3-depend. contribution to Ring effect)•ozone temperature correction•Cloud cover and effective scene height from oxygen A-band absorption (Koellemeijer et al. 2001) incl. ghost vertical column correction•Effective UV albedo (surface reflect.) from 377nm•Spectral fitting window: 326.6-335nm


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Comparison of WFDOAS with groundbased data 56 stations

Brewer/Dobson/SAOZ/M124

– mid-latitudes and tropics agreement to within 1% little seasonal variation (cosine amplitudes below 0.5% in general)

– polar latitudes differences of up to +4 to +8% in winter (dependent on individual stations)

– little seasonal variation (cosine amplitudes below 0.5% in general)

SH Polar

NH Polar

mid-lat

&

tropics

coincidence criteria: 300 km & same day

from Weber et al., ACPD 2004

GOME WFD global validation with ground-based


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SCIAMACHY total O3 with GOME WFDOAS

All O3 data of one day (16 Apr 2003)

in 2.5° latitudinal X 2.5° longitudinal grids, only SCIAMACHY data <90° SZA

comparison of SCIAMACHY and GOME within the same grid

GOME WFDOAS V1.0 SCIAMACHY v5.01


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70°S-23°N –1.5% to –3% (+1-2%)23°N-60°N –1.5% to +3% (+2-3%)

(SCIAMACHY v5.01-GOME-WFD)/GOME-WFD at 16 Apr 2004

SCIAMACHY total O3 with GOME WFDOAS


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tO3: (SCIA v5.01/5.04-GOME WFD/GOME WFD)

Polar LatitudesNorth South

SCIAMACHY to GOMEwinter: –7.5 to +2.5% (+3-5%) summer: –1.5 to 0% (+2%) spring-summer: –1.5 to +4% (+3%) fall-winter: –3 to +1% (+2-4%) no. of bins < 300 strong increase in scatter of mean relative deviation and of RMS


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Mid LatitudesNorth South

SCIAMACHY to GOMEwinter: –2 to +3% (+2-3%) summer-fall: –2 to –0.5% (+1-1.5%) spring-summer: –2 to +1% (+1.5-2%) early winter: within 1% (+2-3%)



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Tropics Global

SCIAMACHY to GOME –2.5 to –0.5% (+1%) –2 to +0.5% (+2%)



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comparison as a function of solar zenith angle (SZA)

one day Jan to June 2003

SCIA to GOMEmean relative deviation: 20° to 60° increase of mean relative deviation with SZA,

>60°to 85° decrease, >85° increase again RMS: >85° SZA RMS much higher than below no dependence to number of bins



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comparison as a function of total ozone

one day Jan to June 2003

SCIAMACHY to GOMEmean relative deviation: increase with total ozone to <390 DU

>390 DU small decrease with total ozone RMS: dependence to no. of bins only for half year mean



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V4.0: V5.0-old: 70°S-80°N -60%–0% 70°S-80°N -60%–0%

(+/-2-15%) (+/-2-15%)

Verification orbits 2508 & 251023 Aug 2002

SCIAMACHYto GOME 3.0

Case1 from 5.0-verif.: 65°S-80°N -7%–15%

(+/-2-15%)

NO2 VCD : (SCIAMACHY-GOME 3.0)/GOME W3.0

Status March 2004no latitudinal dependence!

% e

rror

50 0

latitude

50 0 50

latitude

% e

rror

% e

rror

50 0 50

latitude


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NO2 VCD : (SCIAMACHY-GOME 3.0)/GOME 3.0

Daily comparisons

as function of latitude

from Jan-June2003

v5.01/5.04

% e

rror

% e

rror

50 0 50

latitude

10 Janv5.04

2 Marv5.04

20 Junv5.04

12 Mayv5.01

50 0 50

latitude

% e

rror

% e

rror


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NO2 SCD : (SCIAMACHY-GOME 3.0)/GOME W3.0%

err

or

% e

rror

% e

rror

10 Janv5.04

2 Marv5.04

50 0 50

latitude

12 Mayv5.01

Daily comparisonsas function of latitude

from Jan-June2003

v5.01/5.04

20 Junv5.04

% e

rror

50 0 50

latitude


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NO2 VCD : (SCIAMACHY-GOME 3.0)/GOME W3.0

% e

rror

% e

rror

20 Junv5.04

20 40 60 80

sza

12 Mayv5.01

10 Janv5.04

% e

rror

2 Marv5.04

% e

rror

30 40 50 60 70 80

sza

Daily comparisons

as function of solar zenith angle

(SZA)

from Jan-June2003

v5.01/5.04

SH (solid)NH (light)


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Summary: SCIAMACHY total ozone v5.01/5.04

Global validation with GOME WFDOAS V1 from Jan-June 2003 by fast binning method

Slight underestimation of GOME WFDOAS (within +0.5 to –2%, RMS 2%), in accordance with ACVE-2 results

Results improves when only SCIAMACHY data below 85° or even 75° SZA are used

(Coupled) dependencies to seasons, latitudes and total ozone: • increase of deviation from summer to winter as atmospheric variability

increases• detected in GOME GDP 2.4 (see Lambert et al., 2000) and attributed to:

no temp. correction in O3 cross sections, AMF calculations, atmospheric profile shape effect, spectral analysis when atmosphere optically thick, not including ozone filling-in as part of Ring effect

Update to ~ GDP 4.0 or to WFDOAS of SCIAMACHY total ozone will probably lead to agreements within 1% with groundbased or GOME WFDOAS for SCIAMACHY data <85°!


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Summary: SCIAMACHY total NO2 v5.01/5.04

Global validation with GOME 3.0 from Jan-June 2003 by fast binning method

Results show latitudinal dependence and in Winter-Spring in the Northern Hemisphere strong dependence to SZA!

Results for SCIAMACHY 5.01/5.04 worse then for verification orbits v5.0 case 1 or case 4 (release 3/2004) and the results of ACVE-2!


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ACKNOLEDGEMENTS

DLR & ESA/ESRIN for GOME and SCIAMACHY lv 1 & lv 2 data

For Funding:ESA-ESRIN (AO-project 651 SATVAL and contract 16402/02/I-LG)DLR-Bonn (contract No. 50 EE0025) BMBF (FKZ 01 SF9994, 7ATF42 (GOMSTRAT) within the AFO 2000) European Union (EU project EVK2-CT-2001-00133 CANDIDOZ)


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GOME WFDOAS & TOMS V8

Brewer DS

GOME

TOMS



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GOME WFDOAS & TOMS V8

GOME

TOMS

Thanks to Bob Evans, NOAA


global satellite validation of sciamachy o 3 and n o 2 columns with gome wfdoas /3.0

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