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Status of WG1 Science Plan Issues

Status of WG1 Science Plan Issues. Christoph Schraff Deutscher Wetterdienst, Offenbach, Germany. KENDA LETKF at CNMCA : talk by Lucio Torrisi 3DVar at HMC (Sochi area): not (yet) as good as interpolated GME analyses; will test use of radar radial winds

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Status of WG1 Science Plan Issues

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  1. Status of WG1 Science Plan Issues Christoph SchraffDeutscher Wetterdienst, Offenbach, Germany • KENDA • LETKF at CNMCA : talk by LucioTorrisi • 3DVar at HMC (Sochi area): not (yet) as good as interpolated GME analyses; • will test use of radar radial winds • ARPA-SIM (Virginia Poli): comparison of 1D-Var+nudging and LHN • 1D-Var not as good as LHN • Problem: bias between moist physics of COSMO and diagnostic scheme used in 1D-Var • work will be stopped • at DWD: • Direct nudging of radial velocity • LHN for COSMO-EU • Nudging of GPS-IWV

  2. nudging of radar radial velocity:verif. vs. radar precipitation (1 – 27 May 2012) ETS FSS, 11 g.pts. (30 km) threshold: 0.1 mm / h control (C-DE setup, with LHN) use of radial velocity added 00-UTC forecast runs 12-UTC forecast runs

  3. nudging of radar radial velocity:summary • experiment May 2012 with additional use of vr (control with LHN !) : • small positive impact on (mainly strong) precipitation • otherwise neutral • no show cases with strong positive impact • next: • check and improve efficiency, • add few more tests, • make it operational

  4. Latent Heat Nudging for COSMO-EU • Motivation • Reanalysis Project of HErZ would like to use LHN also on its larger domainconfiguration (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)

  5. LHN for COSMO-EU: radar data coverage • 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

  6. LHN for COSMO-EU: case study hourly precipitation at 2 Aug. 2012, 00 UTC + 4h Radar Control (rout) LHN Experiment

  7. LHN for COSMO-EU:verif. vs. radar precipitation (August 2012) 00 UTC 0.1 mm/h 00 UTC 2.0 mm/h 12 UTC 2.0 mm/h 12 UTC 0.1 mm/h

  8. LHN for COSMO-EU: Summary • LHN in COSMO-EU is beneficial; forecast impact: • Summer: • precipitation improved (esp. convective cases) • most surface parameters slightly improved • Winter: neutral • Work started to extend data coverage using OPERA radar composite

  9. Status of OPERA • 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)

  10. Status of OPERA ODC composite 12 Aug 2013, 15 UTC

  11. Status of OPERA OPERA DC composite (C-DE domain): 1 Z-R relationship ‘EY composite: Input for LHN at DWD, 4 different storm-dep. Z-R relationships 12 Aug. 2013 15 UTC differences particularly for low precip rates; (erroneous spaital alignment ?)

  12. Status of OPERA • 3-D reflectivity and radial wind: • reflectivity sent by almost all member states, • radial wind only by few • (but increasing) • (Courtesy HiddeLeijnse, * 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))

  13. COSMO Science Plan Issues on DA:General strategy • overall strategic goals of COSMO: convective-scale EPS • convective-scale ensemble-based DA • other consortia: focus on 3D-/4D-Var for deterministic, EnKF for EPS • hybrid • Hybrid ‘4D-EnVar’ : without need of TL / adjoint • Environment Canada ! UKMO ? HIRLAM ? • DWD: hybrid 3D-EnVar for global ICON  for COSMO ? • advantages of EnVar over LETKF (for deterministic run !) : • localization on B, not in obs space  better for non-local obs • hybrid approach mitigates sampling error • disadvantages of EnVar over LETKF: • 4D approach limited: Use only obs times where Grib fields used • costs •  COSMO: continue with LETKF

  14. COSMO Science Plan Issues on DA:Action items 2015  2017 (and beyond !) • consolidation of LETKF scheme, wherever found required, • may include extensions: • intrinsic stochastic physics (links to WG3a, WG7) • (other types of) additive covariance inflation • iterative (e.g. running in place like) approaches or latent heat nudging (LHN) in view of improving convection initiation • use of ensemble members with lagged valid time to reduce phase errors • blending techniques to combine information from the larger scales of the nesting model

  15. COSMO Science Plan Issues on DA:Action items 2015  2017 (and beyond !) • integrated forecasting system for nowcasting (NWC) and very short-range-forecasting based on NWP • towards very high resolution (1 km / sub-km) (link to SFP project COSMO-Airport, incl. Mode-S data; sub-km) • towards very high frequent analysis and forecast update (link to HErZ TB1, KENDA with 5-min update using 3-d radar data) • main issue: quality ! (need to match obs, but maintain balance) • optional: ‘higher weights for latest observations’ (smaller obs errors, weaker data thinning) ? smaller localization scales ? • optional: evaluation of assimilation of NWC products as pseudo-obs such as stability indices and objects (using non-conventional metrics)

  16. COSMO Science Plan Issues on DA:Action items 2015  2017 (and beyond !) • extended use of obs (particularly PBL, low-level humidity, cloud, precip) • consolidate obs focused in KENDA PP: radar, GPS slant path, SEVIRI cloud • improved use of screen-level obs (T2m, RH2m, uv10m) • SEVIRI WV (water vapour) channels • AMDAR humidity ; high-resolution aircraft Mode-S (wind) data • microwave radiometer (+ Raman lidar) T-, q- profiles, Doppler wind lidar, ceilometer cloud base height • (SEVIRI VIS for cloud properties, cloud radar data (CALIPSO, EarthCARE 2015) • renewable energy: power data from wind mill farms and solar power systems satellite • no aerosol assimilation : • for COSMO-ART : accurate description of aerosol sources • would require substantial resources

  17. COSMO Science Plan Issues on DA:Action items 2015  2017 (and beyond !) • lower BC (analysis (link to WG3b) + perturbations (link to WG7) !) • soil moisture SM (soil temperature, etc.), e.g. by: • include SM in control vector, add SMOS / ASCAT satellite SM • separate 2-D column analysis: LETKF, or EPS used in Var-SMA • snow cover and depth • SST (perturbations e.g. by pattern generator) • diagnosis: (explore in EnKF framework) use of • FSO (Forecast Sensitivity to Observations) (→ link to HErZ project) • DFS (Degrees of Freedom for Signal) diagnostics • (to assess usefulness of different observation types) • 2017+ : adapt LETKF to ICON-LAM(review decision LETKF – EnVar)

  18. COSMO Science Plan Issues on DA:Action items 2018  2020 • … see previous slides • MTG-IRS • MW + IR radiance over land + in cloudy areas (dep. on experience in global DA) • parameter estimation ? • observation error correlations ?

  19. COSMO Science Plan Issues on DA:risks • insufficient quality of LETKF ( develop EnVar ?) • need to maintain / increase (often temporary) human resources ! Depends on: • continuation of HErZ after 2014 • new fixed position for radar DA • new temporary positions ? • EUMETSAT fellowship submitted by CNMCA: sat data on soil moisture • further increase of involvement e.g. by MCH, ARPA-SIM, CNMCA, … • … new projects / collaboration with academia • new flexible portable scripts may facilitate experimentation + collaboration • with other institutes on a technical level observation error correlations ?

  20. Science Plan issues on data assimilation:Summary • consolidate /refine LETKF wherever required • (enhancement techniques e.g. to correct phase errors; RIP, LHN …) • integrated forecasting system for NWC – (V)SRNWP • obs: radar, GPS slant, cloud; screen-level; SEVIRI WV, MTG IRS, … • lower BC • diagnosis: FSO , DFS • adapt to ICON-LAM (develop EnVar ?)

  21. Science Plan issues on data assimilation:Summary

  22. developments / plansat other consortia • AROME: • EDA: 3DVar with perturbed obs incl. surface ana (AROME 2014, Arpege LBC) later: revisit breeding / ETKF • multiplicative inflation of forecast perturbations: 1.15 (every 3 hrs) • stochastic physics tendencies (SPPT): large-scale, slowly evolving • also tried: microphysics & turbulence parameter perturbations • perturbed surface initial conditions (SST, SM, Rsmin, LAI, Cveg, Z0oro) • coupling with large-scale analysis: tests with Jk term in Var (weak constraint towards coupling data in Var, truncate Jk info at k=20) • Tests with 1-hrly cycles (3DVar) • use of SEVIRI WV over land • issue: model bias with strong diurnal cycle

  23. developments / plansat other consortia • UKMO: • NWP nowcasting system: Nowcasting Demonstration Project (NDP) • 1hrly 4DVar with sub-hrly obs (…, MSG WV + AMVs, radar radial winds; hourly cloud obs (sat + surf), T2m, RH2m, uv10m) + LHN (!) • 12-hour forecast every hour • 40km-FSS beats STEPS (Lagrangian-extrapolation NWC) after 1.8 hrs • forms basis for next-generation UK NWP nowcasting system • generally: towards 4D-EnVar (without need of TL / adjoint ?)

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