1. © Crown copyright Met Office UM 4D-Var Regional Reanalysis Progress Richard Renshaw, Stephen Oxley, Adam Maycock, Peter Jermey, Dale Barker, Tom Green, DingMin Li

2. © Crown copyright Met Office Contents Technical highlights First full reanalysis 2008/9 Validation Developments for 2013/14

3. © Crown copyright Met Office WP2.1 Building capacity for advanced regional data assimilation orography 12km grid 480 x 384 reanalysis period 2008/2009

4. © Crown copyright Met Office Technical Highlights Capability to generate ODBs

5. © Crown copyright Met Office ODB – obs monitoring database ODB stores observations + qc + O-B + O-A +... Established ECMWF database + utilities Array of tools available for free Metview macros (quick look) Obstat (detailed stats / graphics)

6. © Crown copyright Met Office Technical Highlights Capability to generate ODBs Able to archive reanalysis fields in ECMWF mars

7. © Crown copyright Met Office First run 2008/9

8. © Crown copyright Met Office 4 Parallel Streams 2008 2009 A B C D with 1 month overlap for spin-up

9. © Crown copyright Met Office How long to spin up ? rms screen temperature

10. © Crown copyright Met Office How long to spin up ? rms surface pressure

11. © Crown copyright Met Office Var Resolution UM 12km Var 24km

12. © Crown copyright Met Office Var Resolution 4DVar run time: 36km1 node hour 24km3 node hours 12km20 node hours UM T+241.5 node hours

13. © Crown copyright Met Office Var Resolution: 24 vs 36 km

14. © Crown copyright Met Office Observations Surface (SYNOP, buoy, etc) incl visibility Upper air (sonde, pilot, wind profiler) Aircraft AMV (satwinds) GPS-RO Scatterometer winds ATOVS AIRS IASI GPSRO MSG clear sky radiances

15. © Crown copyright Met Office Bias correction of satellite radiances Initial reanalysis: Radiances processed, not assimilated Final reanalysis: Radiances assimilated monthly bias statistics

16. © Crown copyright Met Office Validation Peter Jermey

17. © Crown copyright Met Office Verification - Results +2.7 wtd skill diff +6.6 wtd skill diff +3.2 wtd skill diff Verifying at T+6 – a good analysis should produce a good short range forecast Jan 08 Jul/Aug 08 Sept/Oct 09

18. © Crown copyright Met Office Statistics and EXTREME Statistics!

19. © Crown copyright Met Office First run 2008-2009

20. © Crown copyright Met Office Statistics Standard Statistics Mean Std Dev Range Extreme Statistics Max of Daily Max Max of Daily Min Min of Daily Max Min of Daily Min Icing days, Frost days, Summer days, Tropical Nights Summer Days Count of days for which daily max T>25 degrees Maximum count of consecutive dry/wet days Count of wet days, count of days with precip above 10mm, 20mm. Extreme Statistics are defined as core indices of climate change by The joint CCI/CLIVAR/JCOMM Expert Team on Climate Change Detection and Indices. Wet Days A day on which precip is greater than 1mm Average precip on wet days, max precip on 5 consecutive days, maximum precip on a single day, total precip, precip above 95 th and 99 th percentiles. Percentiles For base period (ERA) 1961-1990 Percentage of days where max temp > 90 th percentile etc … We calculate these statistics for ERA and EURO4M and compare with observations statistics from European Climate Assessment & Dataset ECA&D http://eca.knmi.nl

21. © Crown copyright Met Office Validation of climate indices Peter Jermey

22. © Crown copyright Met Office Validation of climate indices Peter Jermey

23. © Crown copyright Met Office July 2008

24. © Crown copyright Met Office July 2008 Floods ERA EURO4M ERA EURO4M RMS Mean 73 69 -36 -37 Max of 5 Daily Precip/mm mm EURO4M closer to Obs Both models not as wet as Obs EURO4M more detail

25. © Crown copyright Met Office Developments for 2013

26. © Crown copyright Met Office Cloud assimilation NAE assimilates 3D cloud fields from nowcasting system (combines satellite imagery + surface reports) EURO4M will have to rely on using surface reports directly

27. © Crown copyright Met Office Wattisham, 00Z 2012/03/13 AAXX 13004 03590 11238 83504 10064 20060 30240 40352 53002 60001 71022 886// 92350 333 55/// 20411 84703 86706 88708 Cloud from SYNOP reports Peter Francis

28. © Crown copyright Met Office Wattisham, 00Z 2012/03/13 AAXX 13004 03590 11238 83504 10064 20060 30240 40352 53002 60001 71022 886// 92350 333 55/// 20411 84703 86706 88708 Cloud from SYNOP report 847034 oktas Stratus, height 90m

29. © Crown copyright Met Office Wattisham, 00Z 2012/03/13 AAXX 13004 03590 11238 83504 10064 20060 30240 40352 53002 60001 71022 886// 92350 333 55/// 20411 84703 86706 88708 Cloud from SYNOP report 847034 oktas Stratus, height 90m 867066 oktas Stratus, height 180m 887088 oktas Stratus, height 240m

30. © Crown copyright Met Office Precipitation assimilation Operational UK models assimilate radar rainrate (latent heat nudging) For EURO4M, aim to assimilate raingauge accumulations

31. © Crown copyright Met Office Precipitation assimilation Plan Use E-Obs gridded daily precipitations Keith Ngan, Andrew Lorenc, Richard

32. © Crown copyright Met Office Precipitation assimilation Plan Use E-Obs gridded daily precipitations System to disaggregate 24hr accumulations to 6hrs Var outer loop with spin-up problems minimised (analysis increments trigger rain in model). Keith Ngan, Andrew Lorenc, Richard

33. © Crown copyright Met Office Variational Bias Correction Airmass-dependent bias correction of satellite radiances (based on Harris and Kelly, 2001) Currently coeffs c are calculated off-line monthly VarBC will give smooth and automatic updating Code is in place – hope to trial in 2013 (DingMin Li, Andrew Lorenc, Dale Barker)

34. © Crown copyright Met Office Collaboration – Cross-Validation Compare our reanalysis against: SMHI ERA Obs climatologies Peter

35. © Crown copyright Met Office Summary Initial reanalysis is run (2008-9) new validation tools Production reanalysis will be better: satellite radiances surface cloud ODBs and mars archive A final reanalysis aims to include later developments precipitation assimilation variational bias correction

36. © Crown copyright Met Office Questions ?

37. © Crown copyright Met Office Extra slides...

38. © Crown copyright Met Office model orography ERA-Interim Model T255 (80km) Var T159 (125km) Met Office Model 12km Var 24km

39. © Crown copyright Met Office ERA-Interim vs EURO4M 12km, 70 levels 24km 4D-Var 6-hour analysis window assimilate: conventional obs incl vis satellite radiances GPS (ground & RO) Cloud Precipitation Initial state and boundary conditions from ERA- Interim analyses T255 (80km), 60 levels T159 (125km) 4D-Var 12-hour analysis window assimilate: conventional obs satellite radiances

40. © Crown copyright Met Office Observation processing Corrections to radiosonde temperature, surface pressure, - use same as UKMO Global Rejection lists - use old UKMO Global and NAE lists

41. © Crown copyright Met Office Observations from ECMWF Surface (SYNOP, buoy, etc) incl visibility Upper air (sonde, pilot, wind profiler) Aircraft AMV (satwinds) ATOVS AIRS IASI GPSRO MSG clear sky radiances

42. © Crown copyright Met Office Observations from MetDB Ground-based GPS Scatterometer winds

43. © Crown copyright Met Office Verification Description of Work: Temperature, Wind, Water Vapour, Surf. P.,Surf. Radiation Budget, Earth Radiation Budget, Cloud Properties, SST,Precip, Snow Cover, and Visibility. Rel. Hum. Skill Scores (as in NWP Index): Skill = (Per(Anal)) 2 – Fc 2 (Per(Anal)) 2 ETS as (in UK Index): Tot/Base Total Cloud Cloud Base 3, 5, 7 octs. 100m, 500m, 1500m Precip 0.5mm, 1mm, 4mm Vis (1.5m) 200m, 1000m, 4000m

44. © Crown copyright Met Office February 2009

45. © Crown copyright Met Office February 2009 Snow Min of Daily Min Temp/degrees Max of Daily Precip/mm ERA EURO4M

46. © Crown copyright Met Office February 2009 Snow Min of Daily Min Temp/degrees ERA EURO4M ERA EURO4M RMS Mean 2.8 2.3 0.9 0.3 EURO4M closer to Obs EURO4M larger bias EURO4M and ERA warmer than obs

47. © Crown copyright Met Office February 2009 Snow ERA EURO4M ERA EURO4M RMS Mean 7.5 6.2 -0.45 -5.6 Max of Daily Precip/mm EURO4M closer to Obs EURO4M smaller bias EURO4M and ERA dryer than obs

48. © Crown copyright Met Office Reports of 24hr accum precip

49. © Crown copyright Met Office 12Z Reports of 6hr precip

50. © Crown copyright Met Office 00Z Reports of 6hr precip

51. © Crown copyright Met Office 15Z Reports of 6hr precip

52. © Crown copyright Met Office Covariances NAE Old covariances from Global model Horizontal length scales are guesses EURO4M Covariances calculated (NMC method) in CVT Horizontal length scales also from CVT Marek, Gordon, Jean-Francois

53. © Crown copyright Met Office CVT covariances: psi horizontal length scales 350km 100km vertical mode (1 to 70)

54. © Crown copyright Met Office CVT covariances: psi horizontal length scales 350km 100km vertical mode (1 to 70) NAE 180km

55. © Crown copyright Met Office Cov: CVT vs NAE