1. © Crown copyright Met Office CAVIAR Update to Met Office work on field campaigns Stuart Newman Imperial College, 29 March 2011

2. © Crown copyright Met Office Contents This presentation covers the following areas New data Recent work on Camborne B400 case study Improved ARIES profile retrievals CAVIAR 1.0 continuum in LBLRTM Agreement/discrepancies in continuum coefficients

3. © Crown copyright Met Office Recap on ARIES case study data CampaignGood ARIES nadir data?Good ARIES zenith data? Camborne (field of view mis-pointing corrected end 2008) Jungfraujoch Result: lack of data sensitive to the self-broadened continuum in range 800-1200 cm -1 Also desirable to have night-time data to probe spectrum > 2000 cm-1 contaminated by solar radiation in daytime

4. © Crown copyright Met Office New flights during FAAM detachment to Exeter airport CAVIAR evening flight on 7 March VACAR-CAVIAR evening flight on 18 March ARIES performed mostly ok…

5. © Crown copyright Met Office Very preliminary analysis Very dry layer

6. © Crown copyright Met Office Very preliminary analysis Orbits to increase zenith slant path

7. © Crown copyright Met Office Very preliminary analysis

8. © Crown copyright Met Office Very preliminary analysis

9. © Crown copyright Met Office Very preliminary analysis Reduce bias with better T- dependence?

10. © Crown copyright Met Office B400 case (18/9/2008) revisited Look again at retrieving profile information from ARIES monomer channels Characteristics of background errors (matrix of error covariances for temperature and humidity) very important B-matrixAdvantagesDisadvantages ECMWFwell-tested in NWPinflexible, global average toy modelflexiblemay not be realistic campaign- specific directly applicable to case study need good statistics

11. © Crown copyright Met Office Error covariance estimates from dropsondes and radiosondes

12. © Crown copyright Met Office Error covariance estimates from dropsondes and radiosondes Large variance in humidity

13. © Crown copyright Met Office Error covariance estimates from dropsondes and radiosondes Diagonal contains variances 2 : level i versus level i Off-diagonals are covariances ij : level i versus level j

14. © Crown copyright Met Office Error covariance estimates from dropsondes and radiosondes Large variance in humidity near 400 hPa

15. © Crown copyright Met Office Error covariance estimates from dropsondes and radiosondes Can also compute T-q covariances T(level i) versus q(level j)

16. © Crown copyright Met Office ARIES B400 retrievals Temperature

17. © Crown copyright Met Office ARIES B400 retrievals Humidity

18. © Crown copyright Met Office ARIES B400 retrievals Spectral channels used (CO 2 and H 2 O monomer)

19. © Crown copyright Met Office So… in theory now have a better baseline profile of temperature and humidity to probe continuum channels ARIES B400 retrievals

20. © Crown copyright Met Office ARIES B400 foreign continuum Obs-calc residuals are within ± 2 K for continuum-sensitive channels (with LBLRTM as simulation using MT_CKD 2.5)

21. © Crown copyright Met Office Continuum coefficients including ARIES Jungfraujoch results

22. © Crown copyright Met Office Continuum coefficients ARIES nadir data from Camborne in better agreement with MT_CKD and Igor/RAL than Jungfraujoch zenith data outliers

23. © Crown copyright Met Office Continuum coefficients Satellite (IASI) data from Camborne and Jungfraujoch also in reasonable agreement with MT_CKD and Igor/RAL outliers

24. © Crown copyright Met Office CAVIAR 1.0 continuum Thanks to Igor for supplying coefficients Relatively big changes

25. © Crown copyright Met Office Putting new CAVIAR continuum in LBLRTM Interpolate continuum coefficients to 1 cm -1 resolution (instead of 10 cm -1 ) Replace foreign-broadened and self-broadened (260 K and 296 K) coefficients in range 1280-2500 cm -1 as supplied by Igor Seems to run!

26. © Crown copyright Met Office ARIES B400 continuum 1950 cm -1 region stands out

27. © Crown copyright Met Office And finally… far longwave ARIES data Positive bias < 700 cm -1

28. © Crown copyright Met Office Reference with NPL data ARIES performance falls off < 700 cm -1

29. © Crown copyright Met Office Summary and things to do New profile retrievals using ARIES monomer channels, seems to produce better fit to data Water vapour continuum coefficients retrieved from ARIES/IASI nadir data in range 1400-2000 cm -1 are in fairly close agreement with Igor/RAL data, except around 1950 cm -1 where discrepancy is unexplained – able to compare with NPL-FTS data? Continuum coefficients from Jungfraujoch data are still smaller; need to reanalyse these data using ARIES retrievals (as above) Igor/RAL continuum coefficients included in LBLRTM at 1 cm -1 resolution, this seems to work without slowing down program ARIES data at extreme longwave end (overlap with TAFTS) are subject to noise/bias, need to quality control carefully

30. © Crown copyright Met Office Questions and answers

31. © Crown copyright Met Office Field campaign summary: UK (Camborne), Switzerland (Jungfraujoch) FlightDateWeather conditionsNotes B39619.08.08Persistent boundary layer cloudPartial NPL data B39722.08.08Persistent boundary layer cloudPartial NPL data B40018.09.08Good clear sky conditionsSonde chase, good flight B466 16.07.09Cloud at times over JungfraujochPartial NPL data B467 19.07.09Initially thin cirrus which clearedGood NPL data B468 20.7.09Good clear sky conditionsFLASH sonde + MetOp overpass B469 25.07.09Cloud at times over JungfraujochPartial NPL data B470 26.07.09Some thin cirrus encroachingGood NPL data B471 27.07.09Excellent clear sky conditionsMetOp overpass B472 29.07.09Excellent clear sky conditionsARIES failure B473 01.08.09Excellent clear sky conditionsNo TAFTS B474 04.08.09Partial cloud over JungfraujochCancelled am flight, pm only

32. © Crown copyright Met Office Very preliminary analysis

33. © Crown copyright Met Office CAVIAR 1.0 continuum Thanks to Igor for supplying coefficients