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

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Presentation on theme: "© Crown copyright Met Office UM 4D-Var Regional Reanalysis Progress Richard Renshaw, Stephen Oxley, Adam Maycock, Peter Jermey, Dale Barker, DingMin Li."— Presentation transcript:

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

2 © Crown copyright Met Office Contents Progress with technical work First attempt at reanalysis Developments for 2012/13

3 © Crown copyright Met Office Set up and demonstrate an advanced regional reanalysis system Based on operational North Atlantic/Europe LAM Planning to analyse 2010 & 2011 WP2.1 Building capacity for advanced regional data assimilation

4 © Crown copyright Met Office 12km grid 480 x 384 MetO Regional Reanalysis: Horizontal Domain

5 © Crown copyright Met Office Technical work Build a reanalysis system to run at ECMWF taking observations, start file, boundary conditions from ECMWF archives storing analyses in ECMWF archives and producing data to validate the reanalysis.

6 © Crown copyright Met Office Running at ECMWF ECMWF interface Met Office

7 © Crown copyright Met Office Technical Highlights Set up Met Office systems on ECMWF IBM Use observations from mars (ECMWF BUFR format) Preprocess satellite radiances reconstruct level 1b files from BUFR data convert level 1b counts to level 1c radiances (AAPP) map between instrument grids (e.g. AMSU+MHS to IASI) Convert and map ERA-Interim GRIB files to UM file format, for start files and boundary conditions Use CYLC to develop and run a reanalysis suite

8 © Crown copyright Met Office CYLC: Scheduling System CYLC, written by Hilary Oliver (NIWA) + ROSE – adds interfaces and configuration management

9 © Crown copyright Met Office Why CYLC ? Will replace ageing Met Office system Can build, run, monitor suites of any complexity Portable – Open source Flexible Intelligent job scheduling - define dependencies for each task - tasks will run early if possible

10 © Crown copyright Met Office sample CYLC suite

11 © Crown copyright Met Office Dales challenge Regional reanalysis - why bother ??!

12 © Crown copyright Met Office Evidence from operational NWP 25km Global vs 12km NAE

13 © Crown copyright Met Office...the benefits of resolution forecast range screen temperature rms error (K) global 25km NAE 12km

14 © Crown copyright Met Office...and the disadvantage of boundaries! forecast range mean sea level pressure rms error (Pa) global NAE

15 © Crown copyright Met Office ERA-Interim vs 12km EURO4M 12km, 70 levels 36km 4D-Var 6-hour analysis window assimilate: conventional obs incl vis satellite radiances Ground-based GPS 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

16 © Crown copyright Met Office model orography ERA-Interim Model T255 (80km) Var T159 (125km) Met Office Model 12km Var 36km

17 © Crown copyright Met Office First attempt at reanalysis... May 2010 June 2010 July 2010 Floods in Poland, eastern Europe Severe storms France/Spain Russian heatwave spreading West, forest fires

18 © Crown copyright Met Office Poland floods, 16 th May e-obs gridded 24hr rainfall

19 © Crown copyright Met Office Poland floods, 16 th May 2010 Czech Hydrometeorological Institute radar 24hr rainfall

20 © Crown copyright Met Office 12km reanalysis e-obs Poland floods, 16 th May 2010

21 © Crown copyright Met Office ERA-Interim e-obs Poland floods, 16 th May 2010

22 © Crown copyright Met Office Russian heatwave, July 2010 Tmax, e-obs

23 © Crown copyright Met Office Tmax ERA-Interim 12km EURO4M obs

24 © Crown copyright Met Office Verification vs Radiosonde T+0T+6 Temperature rms error ERA-Interim EURO4M 12km

25 © Crown copyright Met Office Verification vs Radiosonde T+0T+6 Vector wind rms error ERA-Interim EURO4M 12km

26 © Crown copyright Met Office Developments for 2012/13 Variational bias correction ODB – obs monitoring Extend observations dataset Cloud and Precipitation assimilation Validation – extreme statistics Collaborate on cross-validation

27 © 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 Work is underway – finish in 2012 (DingMin Li, Dale Barker, Andrew Lorenc)

28 © Crown copyright Met Office ODB – obs monitoring database Established ECMWF database + utilities Array of tools available for free Metview macros (quick look) Obstat (detailed stats / graphics) Replaces several diverse monitoring tools at MO Joint development Currently ~1.5 years into 3 year joint funded post at ECMWF (Peter Kuchta) Setting up Obstat at MO Other NMSs already using ODB (CAWCR, KMA)

29 © Crown copyright Met Office Extend observations dataset Work with UEA (WP2.5) to extend surface and sonde datasets Seeking sub-daily raingauge data...

30 © Crown copyright Met Office Cloud + Precip assimilation Operational UK models assimilate cloud products (satellite) and rainfall (radar, latent heat nudging) For EURO4M, plan to assimilate cloud reports and raingauge accumulations from surface stations Needs development work (2012/13): source sub-daily raingauge accumulations decode and interpret surface reports (Peter Francis) quality control assimilate rainfall accumulations in 4D-Var reduce effect that analysis increments trigger rain in model

31 © Crown copyright Met Office Validation - Extremes High impact weather Should show a benefit for regional reanalysis Focus on: precipitation temperature winds Need to look at probability distributions (pdfs), e.g. number of values outside 10 th /90 th percentile count consecutive days with high/low values accumulated precipitation over several days

32 © Crown copyright Met Office Collaboration – Cross-Validation Compare our reanalysis against: SMHI ERA Obs climatologies Others ?

33 © Crown copyright Met Office Summary Reanalysis system ready to run Already better than ERA-Interim in some features, but not all (yet!) Science development and testing this year

34 © Crown copyright Met Office Questions ? With thanks to: Tom Green, Nigel Atkinson, Sreerekha Tr, others...

35 © Crown copyright Met Office Extra slides...

36 © Crown copyright Met Office First attempt at reanalysis... May 2010 June 2010 July x 1 month runs, with overlap

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

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

39 © Crown copyright Met Office 100km 4D-Var12km 4D-Var Impact of Var resolution

40 © Crown copyright Met Office Verification vs Radiosonde T+0T+6 Relative Humidity rms error ERA-Interim EURO4M 12km

41 © Crown copyright Met Office Global ODB trial output NH Surface T mean (o-b)


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