1. christoph.schraff@dwd.de Introduction to KENDA KENDA Mini-Workshop., Munich, 28 Feb. 2014 1 Introduction to KENDA as COSMO Priority Project Christoph Schraff Deutscher Wetterdienst, D-63067 Offenbach, Germany Motivation, implementation, status Current & future work KENDA: Km-scale ENsemble-based Data Assimilation

2. christoph.schraff@dwd.de Introduction to KENDA KENDA Mini-Workshop., Munich, 28 Feb. 2014  ensemble-based data assimilation component missing & required convection-permitting NWP: after ‘few’ hours, a forecast of convection is a long-term forecast  deliver probabilistic (pdf) rather than deterministic forecast  need ensemble forecast and data assimilation system (strategic aims in COSMO)  forecast component: COSMO-DE EPS developed & operational at DWD perturbations: LBC + IC + physics GME, IFS, GFS, GSM perturb. Motivation : Why develop Ensemble-Based Data Assimilation ?  replace current nudging-based DA by state-of-the-art DA with flow-dependent B

3. christoph.schraff@dwd.de Introduction to KENDA KENDA Mini-Workshop., Munich, 28 Feb. 2014 3 Germany Greece Italy Poland Romania Russia Switzerland  similar configurations  x = 1 – 3 km ~ 2016 :  x  2 km, LETKF  Local Ensemble Transform Kalman Filter (LETKF, Hunt et al., 2007), (because of its relatively low computational costs) Motivation : Why develop Ensemble-Based Data Assimilation ?  data assimilation: priority project within COSMO consortium Km-scale ENsemble-based Data Assimilation (KENDA):

4. christoph.schraff@dwd.de Introduction to KENDA KENDA Mini-Workshop., Munich, 28 Feb. 2014 analysis step (LETKF) outside COSMO code  ensemble of COSMO runs, collecting obs – f.g.  4D -LETKF  separate analysis step code, LETKF included in 3DVAR package of DWD LETKF (km-scale COSMO) : implementation ensemble K deterministic analysis for a deterministic forecast run : use Kalman Gain K of analysis mean  deterministic run must use same set of observations as the ensemble system !  deterministic run may have higher resolution (not optimal if deterministic f.g. deviates strongly from ensemble mean f.g.) x A = x B + K [y o – H(x B )]

5. christoph.schraff@dwd.de Introduction to KENDA KENDA Mini-Workshop., Munich, 28 Feb. 2014 Lucio TorrisiCNMCA (Lucio Torrisi et al.) : LETKF for 10-km COSMO operational perturbed lateral BC :IFS EPS (MCH, ARPA-SIM) Lateral BC / other LETKF implementations lower resolution analysis ensemble (40 members) high resolution deterministic analysis (or at DWD) hybrid EnVar for ICON (GME) variational formulation (Buehner et al 2005)

6. christoph.schraff@dwd.de Introduction to KENDA KENDA Mini-Workshop., Munich, 28 Feb. 2014 Hendrik Reich main development of LETKF at DWD (Hendrik Reich, Andreas Rhodin), main implemented features: adaptive multiplicative covariance inflation (based on Desroziers statistics) adaptive estimation of obs errors in obs space adaptive estimation of obs errors in ensemble space (to account for limited N ens ) adaptive localisation to keep effective N obs constant (to account for limited N ens ) multi-step analysis implementation of LETKF features in KENDA

7. christoph.schraff@dwd.de Introduction to KENDA KENDA Mini-Workshop., Munich, 28 Feb. 2014 DWD:  stand-alone scripts for 2-day period: many LETKF tests, e.g. adaptive methods  LETKF in operational experimentation system NUMEX  slow (archive) Hendrik Reich  ‘BACY’ (basic cycling scripting environment for KENDA, Hendrik Reich): fast (speed: DA with BACY ~ 1 – 2, i.e. ~ 5 – 10 times faster than with NUMEX) largely portable (if obs / GME fields provided) automatic plotting suite model equivalent calculation (MEC) from forecasts for input to verification  potential: tool to ease collaboration with academia scripting environments for LETKF DA cycle also at  MeteoSwiss: 1-hourly LETKF DA cycle for 1 month using conventional obs Chiara Marsigli  ARPA-SIM: first tests, setting up OSSE (Chiara Marsigli) implementation & LETKF tests (so far using TEMP, aircraft, surface, wind profiler)

8. christoph.schraff@dwd.de Introduction to KENDA KENDA Mini-Workshop., Munich, 28 Feb. 2014 Main aim: reach operationability in (mid/end) 2015 system complete (e.g. ana + perturb surface / soil) + robust + efficient quality KENDA ≥ quality nudging-based opr. DA (incl. LHN) (deterministic) (using similar obs set) additional: provide IC perturbations for EPS evaluation of EPS: EPS: how to use KENDA IC perturbations for EPS (COSMO-DE-EPS) Richard Keane (PP COTEKINO / Richard Keane, DWD) replace or rather combine with current IC perturbations Florian Harnisch  HErZ LMU: structure & impact of KENDA IC perturbations (Florian Harnisch) Matthias SommerDiagnostics: FSO (forecast sensitivity of observations) (Matthias Sommer, LMU) KENDA : main short-term goal

9. christoph.schraff@dwd.de Introduction to KENDA KENDA Mini-Workshop., Munich, 28 Feb. 2014 9 KENDA : short-term tasks general testing, tuning, optimization of LETKF setup  specification of observation errors  use of adaptive methods (localisation, cov. inflation, R in ensemble space),  multi-step and multi-scale analysis with different obs / localisation scales  ensemble size (40 ?),  update frequency  a t ? RUC 1 hr   a t  15 min ! (high-res. obs) non-linearity vs. noise / lack of spread / 4D property ? inclusion of additive covariance inflation, Lucio Torrisi probably using self-evolving perturbations (Lucio Torrisi, CNMCA) testing SPPT in DA cycle, possibly also perturbed physics parameters inclusion of LHN (latent heat nudging) (as long as reflectivity not ready for use) robustness: create new ensemble members, if few crash

10. christoph.schraff@dwd.de Introduction to KENDA KENDA Mini-Workshop., Munich, 28 Feb. 2014 10 Extended Use of Observations (1) Aim: (implementation,) forecast improvements from using these observations 3D radar radial velocity Complete obs operator and efficient approximations suitable for DA developed, thinning and superobbing strategies implemented, preliminary DA cycles Yuefei Zeng, Uli Blahak Yuefei Zeng, Uli Blahak (DWD) (Status of Y. Zeng after June 2014 or other resources at DWD unclear) 3D radar reflectivity (direct use) Complete obs operator and efficient approximations suitable for DA developed, thinning and superobbing strategies implemented, preliminary DA cycles Virginia Poli, Tiziana Paccagnella Virginia Poli, Tiziana Paccagnella (ARPA-SIM); Klaus Stephan Theresa Bick Klaus Stephan (DWD), Theresa Bick (U. Bonn)

11. christoph.schraff@dwd.de Introduction to KENDA KENDA Mini-Workshop., Munich, 28 Feb. 2014 11 Extended Use of Observations (2) GPS Slant Path Delay Obs operators (incl. ray tracer) implemented in DWD global 3DVar; Aim: implement complete and efficient obs operator in COSMO by end of 2014 Michael Bender ; Erdem Altunac Michael Bender ; Erdem Altunac (tomography) (DWD) No resources available yet after 2014 for use in LETKF (challenge to use horizontally + vertically non-local obs in LETKF) Cloud Top Height (CTH) derived from Meteosat SEVIRI Fully implemented, single-obs experiments, cycled DA with dense obs for low-stratus cases Annika Schomburg Annika Schomburg (DWD, talk on Monday) Direct use of SEVIRI IR window channels in view of assimilating cloud info Obs operator (RTTOV) + data flow implemented, next monitoring + DA tests Africa Perianez Africa Perianez, DWD, until Feb. 2015, no resources yet thereafter Leonhard ScheckExploratory: SEVIRI VIS/NIR window channels (Leonhard Scheck. LMU)

12. christoph.schraff@dwd.de Introduction to KENDA KENDA Mini-Workshop., Munich, 28 Feb. 2014 12 Extended Use of Observations (3) : Future Mode-S (high-resolution) wind and temperature data (from aircraft) and application to high-res airport model COSMO-MUC (with radar data) Heiner Lange, Tijana Janjic-Pfander Heiner Lange, Tijana Janjic-Pfander (HErZ LMU) Screen-level observations (T-2m, q-2m, uv-10m) (C. Schraff, DWD) (+ Master Thesis at MeteoSwiss on station selection) Direct use of SEVIRI WV channels (for T, qv; for cloud info; linked to IR window) Great interest by HErZ-LMU for a project, starting 2015

13. christoph.schraff@dwd.de Introduction to KENDA KENDA Mini-Workshop., Munich, 28 Feb. 2014 13 thank you for your attention

14. christoph.schraff@dwd.de Introduction to KENDA KENDA Mini-Workshop., Munich, 28 Feb. 2014 14 implementation following Hunt et al., 2007 basic idea: perform analysis in the space of the ensemble perturbations –computationally efficient, but also restricts corrections to subspace spanned by the ensemble –explicit localization (doing separate analysis at every grid point, select only obs in vicinity and scale R -1 ) –analysis ensemble members are locally linear combinations of first guess ensemble members LETKF for km-scale COSMO : method analysis members forecast members

15. christoph.schraff@dwd.de Introduction to KENDA KENDA Mini-Workshop., Munich, 28 Feb. 2014 15 KENDA : Analysis & Perturbation of Lower Boundary Fields Snow cover and depth, idea: apply snow analysis independently to ensemble members (with perturbed obs ?) Sea surface temperature (SST), idea: add perturbations to deterministic analysis Soil moisture (soil temperature) perturbations only: as in EPS (COTEKINO) Longer-term additional tasks Soil moisture (soil temperature) analysis, by using screen-level obs ; 2 ideas:  add 1 analysis level in LETKF for the soil, and apply strong localization for calculating the transform matrix for this level  use the ensemble in current stand-alone variational SMA (perturbations ?) Soil moisture analysis (+ perturbations) using satellite soil moisture data in LETKF Eumetsat fellowship at CNMCA