1. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 1 Recent developments at DWD christoph.schraff@dwd.de Deutscher Wetterdienst, D-63067 Offenbach, Germany based on experiments / plots by Klaus Stephan Direct Nudging of Radar Radial Velocity Data Status of OPERA Latent Heat Nudging for COSMO-EU

2. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 2 nudging of radar radial velocity: methodology pre-processing, done twice (first use time, obs time) for each radar scan 1.at each observation point: correct observed radial wind for sedimentation speed of the hydrometeors calculate observation increment of radial wind component (at obs point) (requires:- bi-linear interpolation of model horizontal wind to obs point - project model horizontal wind to radial direction ) re-folding aliased measurements (according to quality flags of the obs) exclude all increments > ± 5 m/s

3. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 3 nudging of radar radial velocity: methodology 2.at certain model grid points (i,j) (e.g. every 20 km lat / lon) : create vertical profiles of pseudo obs (of radial velocity, as a kind of superobbing) assign all obs increments (at obs points) within ±1° (azimuth) and ±10 km (range) horizontally to this model grid point pseudo obs (of radial velocity) = radial comp. of model wind + obs increment (at model level) (i,j) range 20 km 2° (i,j) model g. pts. get obs increments at model levels as weighted average of increments at obs points (weights depends on height differences) vertical cross section

4. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 4 nudging of radar radial velocity: methodology u mod v mod u pseudo v pseudo Radar model grid pt. pseudo observation in radial wind current model horizontal wind current model radial wind current increment in radial wind current target wind azimuth processing in nudging at each time step : horizontal plain project current model wind to radial direction current observation increment = pseudo observation of radial velocity - model radial velocity increment :- physically: radial velocity - formally: wind vector, always in radial direction !  treat like radiosonde wind increment in nudging scheme

5. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 5 nudging of radar radial velocity: results shown last year control nudge vr 0-UTC runs TSS FF-10m RMSE FF-10m bias, all sta. sta. < 100 m sta. > 800 m 300m < sta < 800m 100m < sta < 300m These differences were due to different external parameters !

6. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 6 nudging of radar radial velocity: verification against radar precipitation 1 – 27 May 2012 assimilation threshold: 0.1 mm / h control (COSMO-DE setup, with LHN) use of radial velocity added FBI ETS

7. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 7 threshold: 0.1 mm / h FSS, 11 g.pts. (30 km) 12-UTC forecast runs nudging of radar radial velocity: verif. vs. radar precipitation (1 – 27 May 2012) 00-UTC forecast runs ETS control (C-DE setup, with LHN) use of radial velocity added

8. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 8 threshold: 5.0 mm / h FSS, 11 g.pts. (30 km) nudging of radar radial velocity: verif. vs. radar precipitation (1 – 27 May 2012) 00-UTC forecast runs ETS control (C-DE setup, with LHN) use of radial velocity added 12-UTC forecast runs

9. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 9 nudging of radar radial velocity: summary nudging of radar radial velocity implemented still code problems with reproducibility (some error rel. to MPI communication) experiment May 2012 with additional use of v r (control with LHN !) :  small positive impact on (mainly strong) precipitation  otherwise neutral  no show cases with strong positive impact next:  fix reproducibility problem, clean up code,  check and improve efficiency  include in official COSMO version,  add few more tests,  make it operational

10. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 10 Status of OPERA currently 27 member states with about 160 radar stations OPERA Phase 4 : spring 2013 – 2018 Programme manager Elena Saltikoff (FMI) User Group established (total 11 p. from NWP, hydrology, biology) three 2-D composites are available every 15 minutes: current rain rate, sum over last hour, current maximum reflectivity Phillipe Lopez (ECMWF) found out: quality has increased in 2013 (with Baltrad QC) but is still not sufficient everywhere best quality over UK, France, Poland and Germany underestimation over southern Europe underestimation in snow cases lots of spurious ground echoes software transforming it to COSMO grids available (Stephan)

11. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 ODC composite 12 Aug 2013, 15 UTC Status of OPERA

12. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 Ref-Talk 19.09. 2012 Radial Wind Assimilation Status of OPERA ‘EY composite: Input for LHN at DWD, 4 different storm-dep. Z-R relationships OPERA DC composite (C-DE domain): 1 Z-R relationship differences particularly for low precip rates; (erroneous spaital alignment ?) 12 Aug. 2013 15 UTC

13. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 13 Status of OPERA 3-D reflectivity and radial wind: reflectivity sent by almost all member states, radial wind only by few (but increasing) (Courtesy Hidde Leijnse, * indicates max. number) HIRLAM already gets access to volume data, but possible also for other consortia dissemination of volume data to member states planned for end of 2014 (to be decided: with or without quality information ?) discussion about meta data / quality issues are ongoing (e.g. to distinguish ‘zero echo’ – ‘no data’ (compare with raw data))

14. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 14 Latent Heat Nudging for COSMO-EU Motivation Reanalysis Project of HErZ would like to use LHN also on its larger domain configuration (COSMO-CORDEX,  x = 7km) Does it work ? Is there a negative interaction between LHN and the deep convection scheme ? Experiments 2 periods: Summer: August 2012 (incl. convective cases) Winter: 1 Nov. – 15 Dec. 2012 (incl. snow cases) operational COSMO-EU setup (Cosmo V4_27, tk?min=0.4) operational LHN setup except: no blacklist information used no bright band detection LHN within first 25 minutes of forecast (will be ~ 2.5h in operational run)

15. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 same data as for COSMO-DE, currently 17 German Doppler radar stations quality controlled 2 Dutch stations 2 Belgian stations 9 France stations 3 Swiss stations 2 Czech stations soon extended by 2 Polish stations every 5 minutes future: can be extended by OPERA composite outside COSMO-DE domain LHN for COSMO-EU: radar data coverage

16. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 hourly precipitation at 2 Aug. 2012, 00 UTC + 4h Radar Control(rout) LHN Experiment LHN for COSMO-EU: case study

17. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 12 UTC LHN ROUT LHN for COSMO-EU: SYNOP verification, summer: positive

18. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 00 UTC LHN ROUT LHN for COSMO-EU: SYNOP verification, winter: slightly positive

19. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 Experiment Control BIAS RMSE LHN for COSMO-EU: TEMP verification, summer / winter: neutral

20. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 Assimilation 0.1 mm/h LHN ROUT LHN for COSMO-EU: Verification against radar precip (summer)

21. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 12 UTC 0.1 mm/h12 UTC 2.0 mm/h 00 UTC 2.0 mm/h 00 UTC 0.1 mm/h

22. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 LHN in COSMO-EU is beneficial; forecast impact: Summer: precipitation improved (esp. convective cases) most surface parameters improved Winter: most surface parameter slightly improved impact on precipitation and low stratus neutral Work started to extend data coverage using OPERA radar composite LHN for COSMO-EU: Summary

23. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 23

24. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 24 nudging of radar radial velocity: verification against radar precipitation 1 – 27 May 2012 precipitation against radar FSS, 11 g.pts. (30 km) threshold : 2 mm / h control (COSMO-DE setup, with LHN) use of radial velocity added assimilation 00-UTC forecast runs12-UTC forecast runs

25. christoph.schraff@dwd.de Nudging Radial Velocity, OPERA, LHN for COSMO-EU COSMO GM, Sibiu, 2 September 2013 25 nudging of radar radial velocity: example radial velocity at lowest elevation (0.5°) of radar site Feldberg (30 Jan. 2012, 21 UTC). observation Azimuth Range (in m) model (COSMO-DE) observation increment Azimuth Range (in m) southwesterly wind above 2500 m a.s.l.