Re: [thredds] use of thredds data server

Hi Isabelle,

if you look into the monthly files for that catalog (http://www.ncdc.noaa.gov/thredds/catalog/gpcp/monthly/catalog.html) there are to types of files gpcp_v2.2_esg.YYYY.gz and gpcp_v2.2_psg.YYYY.gz. Both types of files range from 1979 to 2010 and contain a variable with the same name (precipitation) so I am afraid that the aggregation aggregates both in one single series that goes from 1979 to 2010 and then again from 1979 to 2010 and when you request data from any date up to the last available date (2010-12-01) the Netcdf Subset Service finds the first occurrence of 2010-12-01 in the series but the next date available is 1979-01-01 that is before than the last date requested so it keeps writing data into the response until the second occurrence and you end up getting that file that contains your requested times + 384. One trick, but you'll miss the 2010-12-01 date, is request data from 1991-01-01 to 2010-11-01. Since we don't have control on that THREDDS server I'm ccing Steve Ansari who is the contact that appears in the WMS capabilities document and perhaps he is more helpful.

Cheers,
Marcos.

On 04/17/2012 03:31 AM, isabelle.charon wrote:
Dear all,

Thanks for the very useful tool NetcdfSubset. http://www.ncdc.noaa.gov/thredds/ncss/grid/gpcp_agg/dataset.html I try to use it to extract monthly mean GPCP precipitation, for years from 1991 to 2010, in netcdf format. I obtain a file which contains 624 time steps. I've expected 240: 12 months * 20 years. I think I obtain first the 240 time steps I've required in the file, then the entire archive from 1979 to 2010 (384 time steps more). Can you explain me this think? Is it possible to extract only the 240 time steps?
Thank you very much.

Isabelle Charon (Meteo-France, Frebch meteorology service)

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