1 / 18

Validation of SCIAMACHY total ozone : ESA/DLR V5(W) and IUP WFDOAS V2(W)

Validation of SCIAMACHY total ozone : ESA/DLR V5(W) and IUP WFDOAS V2(W) . M. Weber, S. Dikty , J. P.Burrows , M. Coldewey-Egbers (1) , V. E. Fioletov (2) , S. M. Frith (3) , and D . Loyola (1) Contact : weber@uni-bremen.de DLR Oberpfaffenhofen Environment Canada NASA GSFC.

yule
Download Presentation

Validation of SCIAMACHY total ozone : ESA/DLR V5(W) and IUP WFDOAS V2(W)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Validation of SCIAMACHY total ozone: ESA/DLR V5(W) and IUP WFDOAS V2(W) M. Weber, S. Dikty, J. P.Burrows, M. Coldewey-Egbers(1), V. E. Fioletov(2), S. M. Frith(3), and D. Loyola(1) Contact: weber@uni-bremen.de DLR Oberpfaffenhofen Environment Canada NASA GSFC SQWG Meeting, Bremen, Germany, 13-14 June 2013

  2. The datasets • ESA/DLR V5(W) • WFDOAS V2m(W) • with V7 L1 m-factor • WFDOAS V2(W) • without V7 L1 m-factor

  3. Correlativedatasets • WOUDC database (brewer/dobson/filter) • monthlymean zonal meandata (Fioletov et al. 2002) • Daily stationaverages (collocateddata) • SBUV mergeddata V8.6 • Monthlymean zonal meandata(Frith et al., 2012)

  4. Bias anddriftsof SCIA WFDOAS wrt GOME Drift (%/decade) Bias (% in 2002) w/o m-factors with m-factors

  5. Bias anddriftsof SCIA WFDOAS wrt GOME • GOME stableover a 16 yearperiod • m-factors (Bramstedt et al., 2009 mainlyreducesthedriftsat lowlatitudes, littlechangesabove50° • however, thedriftandbiaspatternlooks a bitmorecomplicated (e.g. someseasonaleffects) Drift (%/decade) Bias (% in 2002) with m-factors

  6. Zonal meancomparisonswith WOUDC • ESA/DLR higherthan WFDOAS (~1.5%), but both in verygoodagreementwith WOUDC (within ~1-2%, ~3-6 DU) • Small (negative) drift evident in ESA/DLR and WFDOAS with m-factorwrtto WOUDC • nosystematicdriftsbetween ESA andWFDm

  7. Zonal meancomparisonswithSBUV V8.6 • Verygoodagreementwith SBUV mergedforboth WFD V2m and ESA V5 (within 2%) • at polar latitudes (high SZA) negative biases in ESA/DLR • gradient in thebiasbetween SCIA and SBUV fromtropicsto high latitudes (biasdecreases) • weak positive driftwith time in thetropics

  8. Collocationwithgrounddata • Collocationcriteria: • 300 km • distanceweighted SCIA averages (withincollocationradius) • Separate comparisonwithdobsonsandbrewers • Seasonalcycle in differencesto Dobson generally larger thantobrewers • constantT in groundretrievals • temperaturesensitivitylower in brewers WFD(m) WFD ESA/DLR Example: comparisonwith Brewer atHohenpeissenberg, Germany (47°N)

  9. Station-by-station comparison • x WFDm: -0.7% WFDm: 0% ESA: +0.5% ESA: +1.0%

  10. Dependenceby SZA WFDm-dobson WFDm-brewer • x ESA-brewer ESA-dobson • Little SZA dependence • SZA dependence in Dobson comparisonrelatedtoseasonalvariations (T issues)

  11. Combinedozoneand SZA dependency: ESA V5 • Low illuminationconditions: high ozoneand/or high SZA: • Bias togroundincreases (straylightissueswithbothgroundandsatellitedata) • Special conditions: ozone hole conditions (verylowozone): • Grounddatatendtounderestimatebyupto 4% (Bernhard et al., 2005)

  12. Combinedozoneand SZA dependency: WFDOAS V2 • Low illuminationconditions: high ozoneand high SZA • Specualconditions: ozone hole conditions (verylowozone

  13. Summary & Conclusion • Verygoodagreementbetween SCIAMACHY (ESA & IUP) and WOUDC & SBUV merged (mostlywithin 1%) • Someissueswith ESA/DLR at polar latitudes (lowbias) • Small differences in biasandseasonalpatterns (ESA/DLR, WFDOAS) in differencesto SBUV and WOUDC aretheresultofslightlydifferingsettings (different scalingsof Bogumil cross-sections, choiceofozoneprofileclimatology, different algorithmapproach, and so on) • The m-factorapproachfor L1 V7 successfullyremovesthedrift in SCIAMACHY total ozonedata (still someissues in thefirstyearofthedatarecord) • WFDOAS V2 with m-factoragreesbetterthan ESA V5, withthenew GTO mergeddataset (based upon GODFIT, Lerot et al. 2014, Chiou et al., 2013) • RECOMMENDATION: GODFIT asthefuture ESA V6 will be an improvementover SGP 5 (see also Lerot et al. 2014)

  14. APPENDIX

  15. DOAS total ozoneretrievalandozonetemperature Weighting function DOAS • DOAS satelliteretrievals (OMI, GOMEs, SCIAMACHY) • 325-335 nm (WFDOAS: 326.6-334.5 nm) • U Bremen retrieval: Weightingfunction DOAS (Coldewey-Egbers et al., 2005, Weber et al., 2005, Lee et al., 2008) • scalartemperatureshift in the a-priori temperatureprofile • effectiveozonetemperature TO3 • Both total ozoneandtemperaturedependon ozonecross-sectionchoice Coldewey-Egbers et al., 2005 Radiation transfer model retrieved total ozone retrieved ozonetemperature

  16. Ozoneandtemperaturetermsin WFDOAS equation GOME • Anti-correlationbetweenozoneandozonetemperatureterm • Depending on fittingwindowsizeandpositioncorrelationrangesbetweenr = -0.4 and -0.6 Coldewey-Egbers et al., 2005

  17. WFDOAS total ozonedatasets& cross-sectionused • WFDOAS appliedto GOME (1995-2011), SCIAMACHY (2002-2012), and GOME-2 (since 2006) • GOME1/ERS : Burrows et al. 1999 (GOME FM), shift: +0.017 nm • SCIAMACHY/ENVISAT: Bogumil et al., 2003 (SCIA FM), scaled 5.3%, shift: +0.008 nm • GOME2/METOP A: Burrows et al., 1999, convolved, shift: +0.017nm • agreementtowithin 1% with WOUDC breweranddobsons • Nevertheless: useof a singlecross-sectiondatafor all instrumentsareneededtobetterunderstandcalibrationdifferencesbetweeninstruments merged WFDOASdatarecord (Weber et al. 2011, 2012 )

  18. Satellitevsground

More Related