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20040301: MARS netCDF file

>From: "Dr. Hans-Juergen Panitz" <address@hidden>
>Organization: Forschungszentrum Karlsruhe - IMK
>Keywords: 200402271038.i1RAcUrV002883  IDV MARS netCDF

Hi-

>thank you very much for your help.
>It works.

I know it's a hack, but... ;-)

>I was also able to create IDV graphics from a netCDF file with MARS convention
>that contains several parameters,
>e.g. geopotential height, T, u,v, and spec. humidity.
>All data are 3D on pressure levels and are available 4 times a day (6 hourly).
>I selected the data for one day only.
>I attach the ncdump output:  ncdump_air_01082000.nc.out
>It was also possible to plot derived quantities like potential temperature tha
> t
>is implemented in the IDV.

Glad to hear this worked.

>But your trick only works if one selects only 1 day.
>
>I tried it with 2 (see attached ncdump output "ncdump_air_01-02082000.nc.out")
> ,
>August, 1. and 2., 2000.
>IDV cannot handle these data. I assume because the time specification is
>seperated into time (0, 600, 1200, 1800) and date (0, 1) with units "days sinc
> e
>2000-8-1".

Your assumption is correct.

>I try to find a solution with the help of the information from the web-sites
>you mentioned (up to now I wasn't successful).

There is no way to handle this currently.  We are discussing this
with the Java netCDF developers to see if we can come up with a solution.
Essentially, there would have to be some way to handle merging two
coordinate variables (day, time) into one.

>Do you have an idea what can be done?
>
>I attach also two PDF-documents related to the MARS-system of ECMWF.
>
>I downloaded them from
>
>http://www.ecmwf.int/publications/manuals/

Thanks. I had looked at these too, but saw nothing documenting the
MARS convention.  We will look into this further, but at this time
have no solution for the multi-day files like the ones you have.
It's too bad that ECMWF is not using something like the CF conventions
for their output.

I'll let you know if we come up with some solution for this.

Don Murray
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