[gradsusr] error with zinterp.gs and gfs_hd nomads

[Adrian Scherzinger]

Jennifer
thanks a lot!
Cheers
Adrian

___________________________
Adrian Scherzinger
Stv. Leiter Wetterprognosen

Genossenschaft METEOTEST
Fabrikstrasse 14, CH-3012 Bern
Tel +41 (0)31 307 26 26
Fax +41 (0)31 307 26 10
adrian.scherzinger at meteotest.ch
http://www.meteotest.ch

******************************************************************
METEOFON - Wetterauskünfte im direkten Dialog mit dem Prognostiker
0900 57 61 52 (CHF 3.13/Min ab Festnetz) So-Fr 5-17:30, Sa 5-13:30
******************************************************************


Am 14.04.2011 16:03, schrieb Jennifer Adams:
>
> On Apr 13, 2011, at 9:25 AM, Adrian Scherzinger wrote:
>
>> hi
>>
>> i have to make wind maps on a certain height above ground with gradsdods
>> and the nomads gfs_hd (0.5) data. To solve this, i use the zinterp.gs
>> function for an area which is quite big (lat 40 70, lon -15 40). The
>> calculation of one timestep takes around 20 minutes.
> That's because you've made a large 3-D request from a GDS of data in 
> GRIB2 format, which takes a long time, especially if you are using 
> 'gradsdods', an old deprecated build, which is not optimized for doing 
> I/O from an opendap server. You are doing the I/O on row by row basis, 
> slamming the server with small requests. zinterp.gs is not designed to 
> work with remote data sets.
>
>
>> however, after one or two timesteps, the zinterp.gs function just takes
>> a few seconds and gradsdods just delivers "entire grid empty" data.
>> the same script with nomads gfs 1 degree or 2.5 degree data is working
>> fine for all timesteps.
> It may be because the server has enabled a DOS after your 20 minutes 
> of 1-row requests. The administrator of the nomads GDS may be willing 
> to check the logs for an explanation of why your data requests are 
> failing.
>
> My suggestion:
> 1. Upgrade to the latest version of GrADS
> 2. Use a separate script to create a local data set (using fwrite or 
> sdfwrite) that is the subset of gfs_hd grid, only the lat/lon/levels 
> that you need for zinterp.gs to work. Optimize this for hitting the 
> server a minimum number of times, and don't ask for more than one 
> level per request -- that will slow down your script.
> 3. After you have a created a local data set, then run zinterp.gs.
>
> --Jennifer
>
>
>
>
>>
>> what is going wrong?
>>
>> thanks for any help
>> adrian
>>
>> -- 
>> ___________________________
>> Adrian Scherzinger
>> Stv. Leiter Wetterprognosen
>>
>> Genossenschaft METEOTEST
>> Fabrikstrasse 14, CH-3012 Bern
>> Tel +41 (0)31 307 26 26
>> Fax +41 (0)31 307 26 10
>> adrian.scherzinger at meteotest.ch <mailto:adrian.scherzinger at meteotest.ch>
>> http://www.meteotest.ch
>>
>> ******************************************************************
>> METEOFON - Wetterauskünfte im direkten Dialog mit dem Prognostiker
>> 0900 57 61 52 (CHF 3.13/Min ab Festnetz) So-Fr 5-17:30, Sa 5-13:30
>> ******************************************************************
>>
>> _______________________________________________
>> gradsusr mailing list
>> gradsusr at gradsusr.org
>> http://gradsusr.org/mailman/listinfo/gradsusr
>
> --
> Jennifer M. Adams
> IGES/COLA
> 4041 Powder Mill Road, Suite 302
> Calverton, MD 20705
> jma at cola.iges.org <mailto:jma at cola.iges.org>
>
>
>
>
> _______________________________________________
> gradsusr mailing list
> gradsusr at gradsusr.org
> http://gradsusr.org/mailman/listinfo/gradsusr
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://gradsusr.org/pipermail/gradsusr/attachments/20110415/7aa8c3a7/attachment-0003.html