Hi Sean,
You can't make depth into a dimension unless it's one-dimensional and
monotonic, which would give it a one-to-one correspondence with
model_level_number. It sounds like that's not the case here.
I believe what you want to do is to declare depth as an auxiliary
coordinate variable by adding the name of the depth variable to the
"coordinates" attribute of your data variables for currents. Sections 5,
5.2 and 6.2 of the CF spec cover auxiliary coordinates.
That ought to be sufficient for depth to be automatically included when
a user selects one of the currents as an output parameter. (And if it's
not, I would say that means the data portal software doesn't understand
CF very well, and needs some fixing up.)
Cheers,
--Seth
Seth McGinnis
NARCCAP Data Manager
IMAGe - CISL - NCAR
On 1/23/2015 3:56 AM, Gaffney, Sean P. wrote:
> Hi everyone,
>
> Sean Gaffney from the British Oceanographic Data Centre here. Apologies
> if I?m posting this in the wrong place, but I could use some advice please.
>
> I?ve been supplied with some numerical model data representing vertical
> and horizontal currents in 40 depth layers in the North Atlantic, as CF
> compliant files. The existing dimensions are longitude, latitude,
> model_level_number and time. However, I?ve also been supplied in the
> file with depth for each 3-D cell, but this has just been supplied as a
> normal variable.
>
> This means that, if someone accesses the BODC model delivery portal,
> unless they explicitly select depth as an output parameter along with
> currents, they won?t get the depth data, but just the model_level_number
> as an indicator of the vertical position of the model output in the
> water column. Feedback from some users is that actual depth values in
> metres are required to make full use of the current data, but that this
> can be lost by having to select depth as an independent additional variable.
>
> I wondered could this potential problem be resolved by converting depth
> into a dimension in the netcdf files? I?m uncertain though of whether
> this will work as the values will be different in every grid point, and
> therefore I?d like advice on whether this is a wise or practical thing
> to do.
>
> Many thanks
>
> Sean Gaffney
> BODC
>
>
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Received on Fri Jan 23 2015 - 08:11:55 GMT
