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Comparison of SCIAMACHY NRT Ozone Columns with GOME Assimilated Ozone Fields. Henk Eskes, Jan Fokke Meirink, Ankie Piters Royal Netherlands Meteorological Institute, De Bilt. GOME ozone data assimilation. TM3DAM: • ECMWF meteo, second moment advection,
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Comparison of SCIAMACHY NRT Ozone Columns with GOME Assimilated Ozone Fields Henk Eskes, Jan Fokke Meirink, Ankie Piters Royal Netherlands Meteorological Institute, De Bilt
GOME ozone data assimilation TM3DAM: • ECMWF meteo, second moment advection, • Gas-phase + heterogeneous chemistry parametrization • Detailed forecast error modelling • KNMI GOME Fast Delivery ozone columns Internet User Service: • 5-day ozone forecast • GOME ozone data bases www.knmi.nl/gome_fd
SCIAMACHY Validation strategy TM3DAM: • Monitoring of Sciamachy ozone columns • SCIA observation minus forecast • Using GOME validation results (D. Balis, J.C. Lambert) Observation minus forecast: • Check on Gaussian statistics • Bias and standard deviation • Dependence on: * latitude, latitude-longitude maps * time * viewing angle * spatial resolution * solar zenith angle * … * cloud parameters
OmF: SCIA vs assimilated GOME Scia NRT Processor 3.53 25/10 to 6/11 (GOME bias corrected)
OmF: latitude dependence Scia NRT Processor 3.53 25/10 to 6/11 (GOME bias corrected)
OmF: distribution Scia NRT Processor 3.53 25/10 to 6/11 (GOME bias corrected) SZA < 60 degree GOME OmF, rms=8DU, Gaussian
Ozone: viewing-angle dependence Scia NRT Processor 3.53 25/10 to 6/11 0.5 sec 1 sec 0.25 sec
OmF: viewing-angle dependence 0.5 sec integr.time Scia NRT Processor 3.53 25/10 to 6/11 GOME bias corr.
CONCLUSIONS: SCIAMACHY NRT total ozone: • Negative bias 20-25 DU Solution: use SCIAMACHY FM ozone cross-sections • Viewing-angle dependence Solution: correct viewing angle • Still biases, especially high Solar Zenith Angles, seasonality Advice: upgrade processor to GOME GDP 3.0 Polarization, realistic cloud information • RMS (noise) very promising: comparable to / better than GOME Validation with data assimilation - OmF differences • Good statistics, to detect subtle effects Small biases, noise statisitics, correlations, jumps in time …
Validation support Validation tools: Sciamachy validation web page: www.sciamachy-validation.org ACVT-MASI activity: Submission of assimilation ozone profiles to NILU
Faraday www.sciamachy-validation.org