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MIPAS Validation Summary - Plenary Session -

MIPAS Validation Summary - Plenary Session -. Herbert Nett ESTEC / EEM-PPP. Measured NESR 0. Radiometric Accuracy. Wavenumber range [cm -1 ]. value. In-flight validation. 685 - 970. 2 * NESR T + 5 % [true source radiance]. Ok. 1570 - 2410. 2 * NESR T + 1 % [true source radiance].

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MIPAS Validation Summary - Plenary Session -

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  1. MIPAS Validation Summary - Plenary Session - Herbert Nett ESTEC / EEM-PPP

  2. Measured NESR0

  3. Radiometric Accuracy • Wavenumber range [cm-1] • value • In-flight validation • 685 - 970 • 2 * NESRT+ 5 % [true source radiance] • Ok • 1570 - 2410 • 2 * NESRT+ 1 % [true source radiance] • Ok • Dynamic range (BB source) • (0 – 230) K • Ok Radiometric Performance • Critical aspects • ice contamination on focal plane optics • non-Linearity of detectors in bands A, AB and B -> strongest impact in band A !

  4. Level 2 algorithm verification: critical aspects • variabilities in target gas signatures (latitudinal, day/night dependencies, perturbed chemistry …) • knowledge of systematic error sources (modelling of instrumental errors, interfering species, spectroscopic errors, Non-LTE ...) • code robustness wrt instrumental effects & extreme atmospheric conditions

  5. VMR (ppmv) Water vapour Ozone N2O Altitude [km] CH4 HNO3 NO2 Orbital coordinate [deg] Results of orbit #504 retrievals: all species

  6. GAIN: gain cal error GRA: horizontal T gradient ILS: ILS shape error Tem: temperature error Hitran: spectrocopy error NLTE: Non-LTE effects [ Extracted from presentation A. Dudhia / U. of Oxford ]

  7. By: H. Oelhaf / FZ-IMK MIPAS-B2 vs. MIPAS-Envisat Comparisons Temperature HNO3

  8. NDSC /O3 sonde & MW radiometer Payerne (av., after 13 Nov) NDSC / Lidar OHP Lauder (NZ) By: J.C. Lambert, V. Soebijanta, BIRA/IABS

  9. MIPAS ECMWF By: A. Dethof / ECMWF MIPAS temperatures • Good agreement of MIPAS temperatures with ECMWF analyzed temperatures over large part of stratosphere (diff < 2%) • Largest differences at 0.1 hPa (ECMWF model top) • MIPAS too cold at bottom end of profiles especially in tropics (cloud contamination?). Improvement after upgrade on 13.11.2002. • Very robust. Same features seen every week. Global averages, 11.-17.11.2002 Departures MIPAS - EC Improvement after 13.11.02

  10. By: A. Dethof / ECMWF MIPAS Ozone • Reasonable agreement with ECMWF ozone over large part of stratosphere • Some differences might be explained by known ECMWF model bias: e.g. – tropical O3 max. lower in ECMWF than MIPAS - 90-65ºN: ECMWF > MIPAS over large part of stratosphere • Unrealistically large MIPAS ozone values in lower stratosphere (cloud contamination?). Improvement after upgrade on 13.11.2002. ECMWF 4.-10.11.02 25.11.-1.12.02 MIPAS Improvement after 13.11.02

  11. Cloud top height distribution in MIPAS measurements (~4100 profiles, 7 – 25 Sep 2002) By: J. Remedios/ U. Of Leicester

  12. MIPAS L2: Geophysical validation

  13. MIPAS L2: Geophysical validation / summary temperature: good agreement with correlative measurements & analyses O3: generally good agreement, bias +1…2 ppmv (?) -> spect. database H2O: too high > 55 km -> Non-LTE (?) too low < 20 km -> cloud contamination, MW choice, conv. thresholds HNO3: bias (-) -> updated spectroscopic data (mipas_hitran v2 -> v3) will yield ~ 10 % higher mixing ratios CH4, N2O, NO2: tendency to vertical oscillations -> T error propagation (‘F’ - ‘R’ difference in detector NL correction/band A) ACVT-MASI: “the MIPAS data set (including also HNO3, CH4, NO2) is the only data set that is self-consistent and can be included in existing assimilation systems” ,

  14. -75° Retrieval altitude-range

  15. Lessons learned / critical areas • potential for reduced total errors by extended MW selection (pT, H2O, …) • perturbations in non-regularised profile retrievals due to oscillations in ‘fw’ – ‘rev’ sweep radiances (re-check after enhanced NL correction scheme in place) • extension of retrieval height range towards higher and lower limb heights will improve the profile accuracy also within the nominal height interval • inaccuracies in spectroscopic line data (incl. error correlations) -> essential also for gephysical validation (HNO3 …)

  16. Baseline modifications: L2 algorithm

  17. MIPAS error budgets • Re-assess total budgets, take into account: - mean profiles and variabilities of contaminants - impact of assumed profile shape above highest tangent altitude - impact of convergence thresholds Reporting ESD & temperature error propagation -> Level 2 products Systematic components (HITRAN, NLTE, gain, ..) -> ’off-line’ information, could be provided as TN & coded data sets (as done for MIPAS Averaging Kernels)

  18. Conclusions • MIPAS in-flight calibration & characterisation tasks completed (some activities & documentation under finalisation) • geophysical validation: first intercomparison results available (ground-based, balloon sensors, assimilation studies, …) • instrument in excellent health, consolidated L0 -> L2 processing chain • stable algorithm baseline (May ‘02->), only minor changes in aux data • important update 13 Nov (LOS pointing correction, L2 tuning parameters) • algorithm update in progress (pT/H2O loop, cloud detection)

  19. Recommendations • Level 1B -> release ok • Level 2: -> release after update of IPF (incl. cloud detection, pT-H2O iteration loop, mipas_hitran v.3.0) • Essential: supply MIPAS data users with • - total error budgets • - averaging Kernels • - spectroscopic database • - reports on geophysical validation campaigns

  20. The MIPAS Calibration & Algorithm Verification Team • P. Mosner/R.Gessner Astrium/D [ instrument engineering / operations ] • G. Perron, G. Aubertin ABB BOMEM [ ESL / Level 1B ] • Th. Fiksel DJO [ L1B&2 s/w engineering ] • S. Bartha Astrium/D [ L2 s/w engineering ] • B. Carli, P. Raspollini IFAC-CNR [ ESL / Level 2 ] • M. Carlotti, M. Ridolfi U. of Bologna [ ESL / Level 2 ] • B. Dinelli ISAC-CNR [ ESL / Level 2 ] • Dudhia, C.D. Rodgers Univ. of Oxford [ ESL / Level 2; project AO # 323 ] • J.M. Flaud LPM/Paris [ ESL / Level 2 ] • M. Hoepfner/H. Oelhaf FZ-IMK [ ESL / Level 2 ] • T.v. Clarmann FZ-IMK [AO#145 & AMIL2DA / L1B&2 analysis ] • M. Lopez-Puertas IAA [ project AO # 304 / L2 analysis ] • M. Birk/G. Wagner DLR-IMF [ project AO # 652 / L1B analysis ] • J.J. Remedios/R. Spang Univ. of Leicester [ project AO # 357 / L1B&2 analysis ] • G. Schwarz DLR-IMF [ ESL / Level 2 ] • ESTEC: J.C. Debruyn, A. Burgess (now U. Oxford), J. Langen, M. Sanchez, H. Nett • ESOC: A. O’Connell (now EUMETSAT), D. Patterson , F. Diekmann, A. Rudolph

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