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Global satellite validation of SCIAMACHY O 3 and N O 2 columns with GOME WFDOAS /3.0

Global satellite validation of SCIAMACHY O 3 and N O 2 columns with GOME WFDOAS /3.0. Astrid Bracher , M. Weber , K. Bramstedt ,M. Coldewey-Egbers, L. N. Lamsal, John Burrows Institute of Environmental Physics (IUP/IFE), University of Bremen

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Global satellite validation of SCIAMACHY O 3 and N O 2 columns with GOME WFDOAS /3.0

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  1. Global satellite validation of SCIAMACHY O3and NO2 columns with GOME WFDOAS/3.0 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 bracher@uni-bremen.de

  2. 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

  3. Comparison of WFDOAS with groundbased data56 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) GOME WFD global validation with ground-based NH Polar mid-lat & tropics SH Polar coincidence criteria: 300 km & same day from Weber et al., ACPD 2004

  4. SCIAMACHY total O3 with GOME WFDOAS SCIAMACHY v5.01 GOME WFDOAS V1.0 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

  5. SCIAMACHY total O3 with GOME WFDOAS (SCIAMACHY v5.01-GOME-WFD)/GOME-WFD at 16 Apr 2004 70°S-23°N –1.5% to –3% (+1-2%) 23°N-60°N –1.5% to +3% (+2-3%)

  6. tO3: (SCIA v5.01/5.04-GOME WFD/GOME WFD) Polar Latitudes North South SCIAMACHY to GOME winter: –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

  7. tO3: (SCIA v5.01/5.04-GOME WFD/GOME WFD) Mid Latitudes North South SCIAMACHY to GOME winter: –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%)

  8. tO3: (SCIA v5.01/5.04-GOME WFD/GOME WFD) Tropics Global SCIAMACHY to GOME –2.5 to –0.5% (+1%) –2 to +0.5% (+2%)

  9. tO3: (SCIA v5.01/5.04-GOME WFD/GOME WFD) comparison as a function of solar zenith angle (SZA) one day Jan to June 2003 SCIA to GOME mean relative deviation: 20° to 60° increase of mean relative deviation with SZA, >60°to 85° decrease, >85° increase again RMS: >85° SZARMS much higher than below no dependence to number of bins

  10. tO3: (SCIA v5.01/5.04-GOME WFD/GOME WFD) comparison as a function of total ozone one day Jan to June 2003 SCIAMACHY to GOME mean 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

  11. NO2 VCD: (SCIAMACHY-GOME 3.0)/GOME W3.0 Verification orbits 2508 & 2510 23 Aug 2002 SCIAMACHY to GOME 3.0 V4.0:V5.0-old: 70°S-80°N -60%–0% 70°S-80°N -60%–0% (+/-2-15%) (+/-2-15%) % error % error 50 0 50 latitude 50 0 latitude Status March 2004 no latitudinal dependence! % error Case1 from 5.0-verif.: 65°S-80°N -7%–15% (+/-2-15%) 50 0 50 latitude

  12. NO2 VCD: (SCIAMACHY-GOME 3.0)/GOME 3.0 Daily comparisons as function of latitude from Jan-June 2003 v5.01/5.04 10 Jan v5.04 12 May v5.01 % error % error 2 Mar v5.04 20 Jun v5.04 % error % error 50 0 50 latitude 50 0 50 latitude

  13. NO2 SCD: (SCIAMACHY-GOME 3.0)/GOME W3.0 Daily comparisons as function of latitude from Jan-June 2003 v5.01/5.04 10 Jan v5.04 12 May v5.01 % error % error 2 Mar v5.04 20 Jun v5.04 % error % error 50 0 50 latitude 50 0 50 latitude

  14. NO2 VCD: (SCIAMACHY-GOME 3.0)/GOME W3.0 Daily comparisons as function of solar zenith angle (SZA) from Jan-June 2003 v5.01/5.04 SH (solid) NH (light) 10 Jan v5.04 12 May v5.01 % error % error 2 Mar v5.04 20 Jun v5.04 % error % error 30 40 50 60 70 80 sza 20 40 60 80 sza

  15. 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°!

  16. 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!

  17. 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)

  18. GOME WFDOAS & TOMS V8 GOME Brewer DS TOMS from Weber et al., ACPD 2004

  19. GOME WFDOAS & TOMS V8 GOME TOMS from Weber et al., ACPD 2004 Thanks to Bob Evans, NOAA

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