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WG 4 activities. 1. COSMO LEPS. Feasibility study of COSMOLEPS at 7 km (cleps_7).

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Feasibility study of cosmoleps at 7 km cleps 7

Feasibility study of COSMOLEPS at 7 km (cleps_7)

  • “Keep the pace” with deterministic model (x~ 2-3 km): if the gap in resolutions between deterministic and probabilistic systems is too large, the two systems go for different solutions (that is, they forecast different weather!).

Motivations:

Provide a more detailed description of mesoscale processes by incresing the horizontal resolution.

Do not lose a “reasonable advantage” against ECMWF EPS, which will go to x=25 km during 2009.

from 10 to 7 km (plus small domain extensions) does not seem a lot


Cosmo leps at 7 km cleps 7 the answer to forecasters dream
COSMO-LEPS at 7 km (cleps_7): the answer to forecasters’ dream?

New system

x = 7 km

z = 40 ML

t = 72 s

ngp = 510x405x40 = 8.262.000

fcst range = 132h

cost = 1925 BU x run

elapsed time = 138 min

Present system

x = 10 km

z = 40 ML

t = 90 s

ngp = 306x258x40 = 3.157.920

fcst range = 132h

cost = 640 BU x run

elapsed time = 45 min

… cleps_7 is about 3 times more expensive than the present configuration

new computer at ECMWF being installed

Computer resources for each ECMWF member state will increase by a factor of 5 (five)  and ….


The dream is possible
The dream is possible

COSMO-LEPS 10 km

COSMO-LEPS 7 km

  • the grid of cleps_7 would be almost identical to that of COSMO-EU, this making easier and cleaner the use of initial fields provided by DWD (e.g. soil moisture analysis).


Future plans 2008 and 2009
Future plans (2008 and 2009)

  • test the use of the Soil Moisture Analysis fields provided by DWD;

  • run cleps_7 for ~ 40 days in autumn 2008 and assess the impact;

  • within TIGGE-LAM, develop coding of COSMO-LEPS output files in GRIB2 format;

  • migration to the new machine at ECMWF;

  • use a better snow analysis (possibly provided by DWD or Meteoswiss);

  • extend the cluster analysis so as to consider not only ECMWF EPS, but also UKMO MOGREPS as global ensemble providing ic’s and bc’s (first tests);

  • implement cosmoleps_7;

  • gaining from COSMO-SREPS experience, introduce more model perturbations;

  • test COSMO-LEPS nested on the under-development ECMWF EDA over MAP D‑PHASE period;

  • optimise use of reforecasts + calibration of wind gust;

  • support CONSENS + verification


2 postprocessing
2. Postprocessing

  • Provide standard interface for internal postprocessing

    • WG6

      WG4: Provide standard internal postprocessing methods (i.e. formula catalog)

  • Instability indices

  • Front parameter

  • Synthetic satellite images

  • Exchange external postprocessing methods

  • KF, MOS on wind, wind gusts


  • 3 use and interpretation of models

    mm/24h

    COSMO-2

    RADAR

    3. Use and interpretation of models

    Forecasters: we all started to use WRF for precipitation!


    3 use and interpretation of nwp models
    3. Use and interpretation of NWP models

    • Serious problems with “non-equilibrium convection cases ». Neither the 7km (parametrised convection) nor the 2km (explicit deep convection) predict precipitation correctly (even yes or no).

    • Who to blame?

    • The bad model(s)?

    • The forecasters overconfident in model(s)?


    The problem
    The problem

    Quality of models

    Expectations from models

    1960

    1970

    1980

    2000

    2010

    1990


    Expectations promises
    Expectations / promises

    • Small grid spacing  high resolution forecast

    • Good (perfect) timing

    • Desire for sophisticated parameters:

      • Surface temperature

      • Rainfall

      • Cloudiness

      • Fog

      • Wind gusts

      • …..

    • Expectations: from forecasters

    • Promises: from modellers


    Discussion points
    Discussion points

    • What is really the quality of a model?

    • Which model is better?

      • In which situation?

      • For which parameter?

    • In a convective situation, do we look a the model rainfall pattern or a TS index? Or synoptics?

    • How does it compare with a statistical postprocessing on a global model?

    • Conditional verification can (must) be used

      • How can forecasters specify the conditions (weather classification, stability, season,…)

    • How can these informations be communicated?


    Wg4 interpretation and applications
    WG4: Interpretation and applications

    Discussion on these topic also started (recently) within SRNWP

    • Catalog and exchange of posprocessing methods

    • Listing and exchange of end-user applications (agriculture, aviation,…)

    • Use and interpretation of models?

      I am open to any collaborative suggestions for activities in this WG.


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