1 / 13

# WG 4 activities - PowerPoint PPT Presentation

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

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about ' WG 4 activities' - rendor

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

### 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?

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 ….

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)

• 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

• 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

• COSMO-2

3. Use and interpretation of models

Forecasters: we all started to use WRF for precipitation!

• 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 forecasters overconfident in model(s)?

Quality of models

Expectations from models

1960

1970

1980

2000

2010

1990

• 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

• 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?

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.