Arpège model input

Dataset specific topics involving WPS.

Arpège model input

Postby beni » Mon Aug 17, 2015 11:09 am

Hello,

Météo France recently opened up gridded numerical forecast model data for its global model, Arpège.
The files are in GRIB2 format, updated 4 times a day, with 6 hours frequency, and in 0.1 degree resolution for Europe (0.5 degree for the rest of the world).
It can be downloaded from here: https://donneespubliques.meteofrance.fr/?fond=produit&id_produit=130&id_rubrique=51

I wondered if there is a way to use it as an input source and boundary condition for a WRF run - Vtable, download sript, etc. Does anyone have experience with this?
beni
 
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Re: Arpège model input

Postby imdnme » Sun Jul 17, 2016 4:20 am

Download script - you can make one yourself, by right-clicking the active (or finished) downloads in your browser and copying the download link. No more than 4 simultaneous downloads are allowed.
Something like:
Code: Select all
http://dcpc-nwp.meteo.fr/services/PS_GetCache_DCPCPreviNum?token=__5yLVTdr-sGeHoPitnFc7TZ6MhBcJxuSsoZp6y0leVHU__&model=ARPEGE&grid=0.1&package=IP1&time=49H60H&referencetime=2016-07-15T06:00:00Z&format=grib2


Using this data in WRF, however, is tricky.
You can make your own Vtables, based on the GRIB codes and variable names from Vtable.ECMWF ( which is for GRIB1), but you need to add 4 columns to the right (GRIB2, for example look at Vtable.GFS).

You also need to split the ARPEGE GRIB2 files, which contain multiple forecast times (arranged by variable), into time-specific files, so ungrib can read them. This can be done by installing and using wgrib2.

ARPEGE file IP1 has the variables GEOPT, T, U, V, RH; file SP1 - Sea level pressure, U10m , V10m, T2m, RH2m; file SP2 - Surface pressure, SKINTEMP, but soil variables seem to be missing completely.

So far I succeeded in making 3 Vtables and running ungrib, but metgrid complains about the missing soil data and stops.
imdnme
 
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Re: Arpège model input

Postby beni » Tue Jun 13, 2017 12:57 pm

Thank you for your help, Imdnme! I've managed to download and use the GRIB files, based on your instructions. I have to say that I'm really amazed by the skills of the forecast made using these datasets. It clearly shows the adventage of Meteo France's data assimilation procedures. I want to encourage everybody to try these datasets instead of GFS!
beni
 
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Re: Arpège model input

Postby beni » Mon Sep 04, 2017 5:08 am

Tip: If you have troubles with the automated download from Météo France's website, there's a guy, mirroring those grib files with bittorrent: http://212.47.238.202/torrents/meteo-france/arpege/
beni
 
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Re: Arpège model input

Postby beni » Fri Sep 22, 2017 12:01 pm

One issue about using ARPEGE data in WPS - the IP1 GRIB files have the geopotential field in "m2 s-2" units. Based on the ECMWF Vtables I figured out that I should use it with the "GEOPT" metgrid name, but it looks like there's no variable with that name in METGRID.TBL.ARW.
Without that, the sea level pressure data in first few hours are very noisy. Does it need some calculation like calc_ecmwf_p.exe or height_ukmo.exe? Any suggestions?
beni
 
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