[Wrf-users] How to use NESDIS snow cover data in WRF

[Ólafur Rögnvaldsson]

Dear fellow WRF-users.

I was wondering if you could assist me in one matter. We would like to start using the daily (more or less) snow cover updates from NESDIS to improve (hopefully:) our operational forecasts here in Iceland.

Could you please inform me about how one should make the most of these data? In particular:

1) Is this the proper ftp-site for downloading the snow-cover (grib) files: ftp://140.90.213.161/autosnow/4kmNH/ ?
2) What changes should one make to the Vtable file?
3) Is there some code modification (and/or additions) that need to be done to WRF and/or WPS?

In particular, I was unable to ungrib this file:

ftp://140.90.213.161/autosnow/4kmNH/NH4km_autosnow_11042012.grb

using this Vtable snipped:

GRIB1| Level| From |  To  | metgrid  | metgrid | metgrid                                 |GRIB2|GRIB2|GRIB2|GRIB2|
Param| Type |Level1|Level2| Name     | Units   | Description                             |Discp|Catgy|Param|Level|
-----+------+------+------+----------+---------+-----------------------------------------+-----------------------+
  42 |   1  |   0  |      | SNOWCOVER| 0/1     | Snow cover                              |  0  |  1  | 42  |   1 |

as I get the following error message:

or at dofri:~/dofri/wrf/V3.3.1/WPS$ ./ungrib.exe 
 *** Starting program ungrib.exe ***
Start_date =  2012-11-04_08:10:00 ,      End_date = 2012-11_04_08:20:00
output format is WPS
Path to intermediate files is ./
 ungrib - grib edition num            2
ERROR: Time unit in ipdtmpl(8), 4 is not suported
Warning: ieee_inexact is signaling
FORTRAN STOP

Looking forward to read your advice.

Kind regards, Óli.
--
Kveðja/regards,
Ólafur Rögnvaldsson
Reiknistofa í veðurfræði - Belgingur
www.riv.is - www.belgingur.is