1. Page 1 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Evaluation of Envisat data using a NWP Assimilation System: A vortex-centred view Authors: W.A. Lahoz, S. Migliorini, R. Bannister, R. Brugge, A. O’Neill Data Assimilation Research Centre, Reading, UK Thanks: ESA, Envisat cal-val teams, Met Office (UK), CNR.IFAC, BADC

2. Page 2 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Talk overview  Aims  Methodology  Results - Qualitative - Quantitative  Conclusions  Further Work

3. Page 3 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Aims  Evaluate L2 GOMOS, MIPAS & SCIAMACHY data (AOID 1039)  Height-resolved and total column data - Temperature - Ozone - Water vapour

4. Page 4 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Methodology  Apply to L2 data (unassimilated): vortex-centred view  Vortex-centred view used to look at UARS MLS water vapour data (Lahoz et al, JAS 1994; QJRMS 1996)  Self-consistency  Comparison against independent datasets  Qualitative/quantitative comparisons  Later: apply to L2+ data (assimilated into a NWP system)

5. Page 5 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Results: qualitative  24/Oct/2002  Geopotential Height: Met Office 12 GMT  1, 10, 100hPa  MIPAS orbit track 18.42 – 19.30 GMT 1hPa10hPa 100hPaOrbit track S E GM ID

6. Page 6 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Results: qualitative  24/Oct/2002  Temperature MIPAS (top)  Temperature Met Off (bottom)  Along orbit track SE SE 1hPa 10hPa 100hPa 1hPa 10hPa 100hPa

7. Page 7 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Results: qualitative  24/Oct/2002  Ozone MIPAS (top)  Water vapour MIPAS (bottom)  Along orbit track SE SE 1hPa 10hPa 100hPa 1hPa 10hPa 100hPa

8. Page 8 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Results: qualitative  24/Oct/2002  CH4 MIPAS (top)  N2O MIPAS (bottom)  Along orbit track SE SE 1hPa 10hPa 100hPa 1hPa 10hPa 100hPa

9. Page 9 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Results: qualitative  24/Oct/2002  HNO3 MIPAS (top)  NO2 MIPAS (bottom)  Along orbit track SE SE 1hPa 10hPa 100hPa 1hPa 10hPa 100hPa DayNight

10. Page 10 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Results: qualitative  27/Sep/2002  MIPAS v sondes (Ny Alesund: 78.9N, 11.9E)  Temperature (top; K)  Ozone (bottom; ppmv) 1hPa 1000hPa 180300 1hPa 1000hPa 015

11. Page 11 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Results: qualitative  27/Sep/2002  MIPAS v sondes (Payerne: 46.8N, 7.0E)  Temperature (top; K)  Ozone (bottom; ppmv) 1hPa 1000hPa 180300 0 1hPa 1000hPa 15

12. Page 12 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Results: qualitative  27/Sep/2002  MIPAS v sondes (Marambio: 64.3S, 56.7W)  Temperature (top; K)  Ozone (bottom; ppmv) 1hPa 1000hPa 180300 1hPa 1000hPa 015

13. Page 13 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Results: qualitative  25/Sep/2002  Total ozone column SCIAMACHY & footprint  Total ozone column analyses (KNMI/ ESA)

14. Page 14 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Results:quantitative  MIPAS v Sonde ( x AK)  Jokioinen (60.8N, 23.5E)  18 Sep 2002  Chi-squared test  Temperature (K) MIPAS Averaging Kernels Red star: MIPAS Green diamond: Sonde x AK

15. Page 15 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Results:quantitative  MIPAS v Sonde ( x AK)  Ny Alesund  200hPa->10hPa  September 2002  Ozone (LH)  Temperature (RH) +1+1

16. Page 16 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Results:quantitative  MIPAS v Sonde( x AK)  Several stations  200hPa->10hPa  September 2002  Ozone (LH)  Temperature (RH)

17. Page 17 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Results: quantitative  23/Sep/2002  Histogram  SCIAMACHY – KNMI/ESA (Total ozone / DU)  GOME bias not removed

18. Page 18 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Results: quantitative  24/Sep/2002  Histogram  SCIAMACHY – KNMI/ESA (Total ozone / DU)  GOME bias not removed

19. Page 19 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Results: quantitative  25/Sep/2002  Histogram  SCIAMACHY – KNMI/ESA (Total ozone / DU)  GOME bias not removed

20. Page 20 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Data Assimilation  Struthers, Brugge, Lahoz, O’Neill & Swinbank, JGR 2002  Cal-val:O: Observations, A: Analyses, B: Background/Forecast - Impact of observations: OSEs - Stability & Bias: O-A differences - Normality of Errors: O-B histograms - Best Linear Unbiased Estimate (BLUE): rms(O-A) - Comparison against independent data

21. Page 21 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Conclusions MIPAS: results suggest:  Consistency between MIPAS data & meteorology  Temperature, ozone vs independent data (sondes x AK): - temperature better characterised than ozone; unrealistic vertical oscillations in temperature retrieval - ozone errors too small (systematic error needed); ozone has a positive bias - MIPAS temperature and ozone errors are close to Gaussian

22. Page 22 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Conclusions SCIAMACHY: results suggest:  SCIAMACHY total column ozone data agrees well with GOME analyses (N.B. GOME biases not removed): - bias magnitude ~  6DU (bias can be positive/negative) - std of differences ~20 DU (Errors are close to Gaussian) - consistent with GOME analyses bias (see BIRA/IASB web-site) GOMOS  Air density in GOMOS needed work (Sep); may be OK now

23. Page 23 Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002 Further Work  MIPAS water vapour data (compare vs balloons)  SCIAMACHY total ozone column biases  GOMOS data (ozone, water vapour)  Assimilation into Met Office system (MIPAS ozone data assimilated for 6 hours & evaluating experiment) - Cal-val - Combine limb and nadir geometries: ASSET project - Averaging kernels/theory