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First Results on Verification of LMK Test Runs Basing on SYNOP Data

First Results on Verification of LMK Test Runs Basing on SYNOP Data. Lenz, Claus-Jürgen; Damrath, Ulrich claus-juergen.lenz@dwd.de; ulrich.damrath@dwd.de. Overview. survey on LMK test runs performed verification results summary and outlook. Survey on LMK experiments performed (1)

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First Results on Verification of LMK Test Runs Basing on SYNOP Data

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  1. First Results on Verification of LMK Test RunsBasing on SYNOP Data Lenz, Claus-Jürgen; Damrath, Ulrich claus-juergen.lenz@dwd.de; ulrich.damrath@dwd.de 21.11.2014 - 1 -

  2. Overview • survey on LMK test runs performed • verification results • summary and outlook 21.11.2014 - 2 -

  3. Survey on LMK experiments performed (1) - center of model area 10° E, 50° N - 421 x 461 grid points horizontally - grid length: 2.8 km - 50 vertical layers, height of lowest layer: 40 m, height of lowest half level: 22 m above ground - values for initialisation and boundaries from operational LM run 21.11.2014 - 3 -

  4. Survey on LMK experiments performed (2) testsuites performed for winter (Januar 2004) 21.11.2014 - 4 -

  5. Survey on LMK experiments performed (3) testsuites for summer (July 2004) und autumn (September 2004) - time integration: TVD Runge-Kutta 3. order, time step: Δt = 30 s - scheme for horizontal advection: upwind 5. order - prognostic calculation of precipitation - thermodynamics: advection of T=T0+T* - relaxation at lateral boundaries: explicit formulated cosine function 21.11.2014 - 5 -

  6. LM and LMK: TSS precipitation rates > 0.1 mm/h (top left), > 2 mm/h (top right), > 10 mm/h (left) January 2004, 00 h runs 21.11.2014 - 6 -

  7. Frequency Bias (FBI) for coverage due to low clouds July 2004, 00 h runs cloud coverage <= 2/8 cloud coverage >= 6/8 21.11.2014 - 7 -

  8. Bias (mean error) for 2 m temperature, July 2004, 00 h runs 21.11.2014 - 8 -

  9. LM and LMK: TSS for precipitation rates > 0.1 mm/h (top left), > 2 mm/h (top right), > 10 mm/h (left) September 2004, 00 h runs 21.11.2014 - 9 -

  10. Bias (mean error) for 2 m temperature, September 2004, 00 h runs 21.11.2014 - 10 -

  11. prec. > 2 mm/h prec. > 0.1 mm/h sensitivity of TSS for precipitation with respect to Latent Heat Nudging 07 - 19 July 2004, 12 h runs prec. > 10 mm/h 21.11.2014 - 11 -

  12. prec. > 2 mm/h prec. > 0.1 mm/h sensitivity of TSS for precipitation with respect to interpolation method LMK, experiment 701 September 2004, 12 h runs prec. > 10 mm/h 21.11.2014 - 12 -

  13. Summary: - gusts (not shown here): enhanced forecast accuracy in LMK due to finer grid resolution - precipitation: results of the smaller scale model lead to partly better verification results than the LM routine forecast - different tests (e.g. introduction of a parameterization scheme for shallow convection, data assimilation) lead to higher accuracy for some parameters, but other parameters may be affected negatively - interpolation method during verification: higher TSS values at small precipitation rates and lower TSS values at higher precipitation rates using a larger averaging area than the nearest grid point 21.11.2014 - 13 -

  14. Outlook: - further continuous work on verification of past and future LMK experiments - development of a tool for application of conditional verification is ongoing - calculation of synthetic radar images using the radar simulation model by Haase (1998) - verification of LM and LMK using the synthetic radar images 21.11.2014 - 14 -

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