Hi Alejandro,
maybe it is worthwhile to have a look at the "section" definition of the
proposal for Point Observation Measurements (Trac #37): *section*: a
collection of profiles which originate along a trajectory. This
definition seems to be quite close to your satellite track explanation.
**
A lot of additional information and examples can be found on the
accompanied wiki
(
https://cf-pcmdi.llnl.gov/trac/wiki/PointObservationConventions).
Best wishes,
Martina
Bryan Lawrence wrote:
> Hi Alejandro
>
>
>> This is a satellite track. Model data will be sampled along this
>> satellite track, and the data will be stored as a 'curtain' of vertical
>> profiles, with each point defined by (lon,lat,time).
>>
>
> I suspected as much :-)
>
>
>> This coordinate is defined in the MIP tables for CMIP5
>> but the standard name is missing (the MIP name is 'location'). My
>> understanding is that all CMIP5 variable and coordinate names have to be
>> mapped to CF standard names, but I'm not 100% sure about this. I will
>> find out whether a standard name is always required.
>>
>
> Well, currently, I think "the official position" might be that standard names
> are only for physical variables, but this is a rather interesting and important
> special case ...
>
> ... and in the absence of a convention extension which covers this
> properly, the following is my gut feeling:
>
> In terms of information content it's just a special case of a timeseries of
> station data, but where the word "station" is inappropriate, what we've
> actually got is the subsatellite_location
>
> Example 5.4
> http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.4/ch05s04.html
> suggests that one doens't need standard names for the variables
> for the station list, and my gut feeling is that we probably don't
> from a CF point of view for this example either.
>
> It become a CMIP5 issue. I suspect for this instance we just need
> to agree the CMIP5 long name which is more useful than
> "location", and I think it should probably be something like
> subsatellite_location (and we probably need which satellite
> in the metadata too).
>
> But none of the above is authoratative :-)
>
>
> (Which MIP table are you looking at? Can you give me the
> context, perhaps in offline email, this is of some interest to me for
> a number of reasons.)
>
> Bryan
>
>
>
>
>
>> Cheers,
>>
>> Alejandro
>>
>> On Wed, 2009-09-16 at 09:49 +0100, Bryan Lawrence wrote:
>>
>>> Hi Alejandro
>>>
>>>
>>>> This is going to be used as the horizontal
>>>> dimension for a stream of atmospheric vertical profiles (e.g.
>>>> temperature(position,height)). It will be an index running from 1 to N
>>>> (number of profiles). Then, the variables [latitude(position),longitude
>>>> (position),time(position)] will give the geographical position and time
>>>> of the profiles. Is there any CF standard name suitable for this?
>>>>
>>> this is really a special case of the observational data issue.
>>>
>>> we have this with profiles from flights, ships etc, intersections between observations on the ground and swaths overhead etc ...
>>>
>>> So, in this case, is there an intrinsic meaning (as Jonathan is implicitly asking)? What
>>> does this position actually mean?
>>>
>>> Bryan
>>>
>>>
>>> On Wednesday 16 September 2009 08:58:54 Jonathan Gregory wrote:
>>>
>>>> Dear Alejandro
>>>>
>>>> Ah, I see. No, I don't think there is a standard name for that. If the index
>>>> had some meaning e.g. if it was a standardised station number, a standard name
>>>> could indicate that. If it is purely an index with no intrinsic meaning, I am
>>>> not sure that it would add any information to give it a standard name. What do
>>>> you think? In a sense, I would say that the variable exists only because it is
>>>> not possible to construct the netCDF file without it. All you're really
>>>> interested in is its dimension.
>>>>
>>>> Cheers
>>>>
>>>> Jonathan
>>>> _______________________________________________
>>>> CF-metadata mailing list
>>>> CF-metadata at cgd.ucar.edu
>>>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>>>>
>>>>
>>>
>>>
>
>
>
>
--
---- Integrated Climate Data Center (ICDC) ----
Martina Stockhause
University of Hamburg / KlimaCampus
Grindelberg 5
D-20144 Hamburg
Germany
phone: +49-40-42838-7780
FAX: +49-40-42838-7711
e-mail: martina.stockhause at zmaw.de
ICDC: www.icdc.zmaw.de icdc at zmaw.de
-----------------------------------------------
Received on Thu Sep 17 2009 - 00:55:46 BST
