Philip,
I agree that referring to versioned std_name tables is generally a good
idea. The WMO members have (and still have) problems with versioning, in
particularly when I think about grib-tables.
I still have a bad feeling about using a name like
wmosynop_high_cloud_area_fraction or isccp_high_cloud_area_fraction in
particularly since they give a over-specification of a generally well
understood phenomenons. Both wmosynop and isccp are
measurements/measurement networks, and CF generally does not have enough
metadata to cover all measurement-details. E.g. for air-temperature, it
is from a measurement point of view often important what type of
instrument has been measuring it (automatic, human, scale,...). We don't
have a 'human_quicksilver_air_temperature' in CF (or a
wmosynop_air_temperature). For comparing 'air_temperature' between
measurements and possibly different models, the generally understood
'air_temperature' is best.
With high-clouds, this is a similar problem. high, medium and low clouds
is generally well understood and well documented in literature (a simple
search on the net gives more than enough hits).
From a model point of view, I cannot estimate if a cloud is exactly the
one type or the other. There are often estimations like:
sigma < 0.4 -> high cloud
0.4 > sigma > 0.7 -> medium cloud
sigma > 0.7 -> low cloud
It will be difficult for the modeller to say: This is a cloud according
to the wmosynop definition.
Therefore, I think we need at first a general CF-name for
high/medium/low cloud to be able to compare in between measurement
networks and models. ISCCP, WMO synop and models have already the
concept of these clouds, they are not a 100% match, but close enough.
If then one of these networks needs a more exact definition of
high/medium/low clouds, they should ask for a std_name of their own.
Best regards,
Heiko
On 2012-05-14 22:59, Cameron-smith, Philip wrote:
>
> Hi Heiko, Eizi,
>
> You make a good point that any standard, such as WMO or ISCCP, may change. However that is also true for CF, and furthermore I think it is likely that other people will want other cloud description standards in the future, including any changes to your WMO-synop standard.
>
> My suggestion for dealing with this is to use the name of the cloud standard in the CF std_name, and then put details and a version number in the std_name description. This will make it precise, and easily extendable in the future.
>
> BTW, I didn't immediately recognize what you meant by 'synop', although it became more obvious after a quick google search. It initially sounded to me like it was a non-specific reference to synoptic scales. If we do decide to use it as part of the std_name, would it be appropriate to call it 'wmosynop' or 'wmo_synop'?
>
> Best wishes,
>
> Philip
>
> -----------------------------------------------------------------------
> Dr Philip Cameron-Smith, pjc at llnl.gov, Lawrence Livermore National Lab.
> -----------------------------------------------------------------------
>
>
>
>> -----Original Message-----
>> From: TOYODA Eizi [mailto:toyoda at gfd-dennou.org]
>> Sent: Monday, May 14, 2012 1:12 AM
>> To: Heiko Klein
>> Cc: Cameron-smith, Philip; Jonathan Gregory; cf-metadata at cgd.ucar.edu
>> Subject: Re: [CF-metadata] Standard_name for cloud-cover by phenomenon
>>
>> Hi Heiko,
>>
>> Sorry about perturbing.
>>
>> You're right. Currently nobody has requested other "low cloud fraction
>> area" such as ISCCP's.
>> And I should have add one thing: "low cloud" in ISCCP is simply defined
>> using height, so it is possible to describe it using vertical axis.
>> Our
>> synop case is different.
>>
>> Best Regards,
>> Eizi
>> ----- Original Message -----
>> From: "Heiko Klein"<Heiko.Klein at met.no>
>> To: "TOYODA Eizi"<toyoda at gfd-dennou.org>
>> Cc: "Cameron-smith, Philip"<cameronsmith1 at llnl.gov>; "Jonathan
>> Gregory"
>> <j.m.gregory at reading.ac.uk>;<cf-metadata at cgd.ucar.edu>
>> Sent: Monday, May 14, 2012 4:01 PM
>> Subject: Re: [CF-metadata] Standard_name for cloud-cover by phenomenon
>>
>>
>>> Hi,
>>>
>>> the idea of putting a source of the definition to the name makes
>> sense if
>>> you want to include several definitions. This is the case for
>>> cloud_area_fraction and isccp_cloud_area_fraction. So, if we had
>> already
>>> one definition of high_clouds, I would go for the SYNOP_high_clouds.
>> But
>>> we currently don't have several definitions, and CF should make it's
>> own
>>> one. And we currently agree very well on which definition to use.
>>>
>>> I don't like the idea of putting the responsibility for the
>> definition
>>> into others hands. If the SYNOP definition changes, the CF-definition
>>> should not. CF-definitions should be self-describing and not rely on
>> other
>>> parties.
>>>
>>> Even if we used a prefix, we would still need the 'type' as discussed
>> in
>>> the beginning of this thread, i.e. because high is neither altitude
>> nor
>>> height, but a implicit name. So I would currently still prefer
>>>
>>> high_type_cloud_area_fraction
>>> middle_type_cloud_area_fraction
>>> low_type_cloud_area_fraction
>>>
>>> Best regards,
>>>
>>> Heiko
>>>
>>>
>>> On 2012-05-13 20:12, TOYODA Eizi wrote:
>>>> Hi Philip,
>>>>
>>>> Your idea makes sense at least for me.
>>>> My bottom line is to avoid being forced to use vertical axis to
>> identify
>>>> types of clouds.
>>>>
>>>> One thing: WMO is umbrella for too many programmes. So it is a bit
>>>> unclear to specify cloud definitions in operational synoptic
>>>> meteorology. So following might be clearer.
>>>>
>>>> SYNOP_high_cloud_area_fraction
>>>> SYNOP_middle_cloud_area_fraction
>>>> SYNOP_low_cloud_fraction
>>>>
>>>> (Heiko, what do you think? ?)
>>>>
>>>> Eizi
>>>> ----- Original Message ----- From: "Cameron-smith, Philip"
>>>> <cameronsmith1 at llnl.gov>
>>>> To: "Jonathan Gregory"<j.m.gregory at reading.ac.uk>;
>>>> <cf-metadata at cgd.ucar.edu>
>>>> Sent: Friday, May 11, 2012 4:19 PM
>>>> Subject: Re: [CF-metadata] Standard_name for cloud-cover by
>> phenomenon
>>>>
>>>>
>>>>> Hi All,
>>>>>
>>>>> I am not wild about using 'type'. I had to read the terms several
>>>>> times before I figured out what was being meant, because I could
>> read
>>>>> it different grammatical ways.
>>>>>
>>>>> A second problem is that it seems a particular definition will be
>>>>> linked to these terms (or did I miss something?), yet someone might
>>>>> reasonably want to use a different definition for high/middle/low
>>>>> clouds in the future.
>>>>>
>>>>> Although I generally don't like including the origin of the data in
>>>>> the std_name, I think this may be an exception. I would suggest
>> using
>>>>> either
>>>>>
>>>>> ISCCP_high_cloud_area_fraction
>>>>> ISCCP_middle_cloud_area_fraction
>>>>> ISCCP_low_cloud_fraction
>>>>>
>>>>> or
>>>>>
>>>>> WMO_high_cloud_area_fraction
>>>>> WMO_middle_cloud_area_fraction
>>>>> WMO_low_cloud_fraction
>>>>>
>>>>> I note that isccp_cloud_area_fraction is already an accepted
>> std_name,
>>>>> so the suggestions above follow naturally.
>>>>>
>>>>> This would also allow changes to the high/middle/low definitions in
>>>>> the future. This would be a problem if there is a proliferation of
>>>>> definitions, but I doubt this will be a problem.
>>>>>
>>>>> Best wishes,
>>>>>
>>>>> Philip
>>>>>
>>>>> -------------------------------------------------------------------
>> ----
>>>>> Dr Philip Cameron-Smith, pjc at llnl.gov, Lawrence Livermore National
>> Lab.
>>>>> -------------------------------------------------------------------
>> ----
>>>>>
>>>>>
>>>>> -----Original Message-----
>>>>> From: cf-metadata-bounces at cgd.ucar.edu
>>>>> [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of Jonathan
>> Gregory
>>>>> Sent: Tuesday, May 08, 2012 7:10 AM
>>>>> To: cf-metadata at cgd.ucar.edu
>>>>> Subject: Re: [CF-metadata] Standard_name for cloud-cover by
>> phenomenon
>>>>>
>>>>> Dear Heiko
>>>>>
>>>>>> I just had a short side-discussion with Eizi, and we settled on
>>>>>> 'type', i.e. we propose the standard names:
>>>>>>
>>>>>> high_type_cloud_area_fraction
>>>>>> middle_type_cloud_area_fraction
>>>>>> low_type_cloud_area_fraction
>>>>>
>>>>> These look fine to me. As you said to John, I hope that "type"
>> would
>>>>> trigger
>>>>> people to look up the definition.
>>>>>
>>>>> Best wishes and thanks
>>>>>
>>>>> Jonathan
>>>>> _______________________________________________
>>>>> CF-metadata mailing list
>>>>> CF-metadata at cgd.ucar.edu
>>>>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>>>>> _______________________________________________
>>>>> CF-metadata mailing list
>>>>> CF-metadata at cgd.ucar.edu
>>>>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>>>>
>>>> _______________________________________________
>>>> CF-metadata mailing list
>>>> CF-metadata at cgd.ucar.edu
>>>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>>>
>>> --
>>> Dr. Heiko Klein Tel. + 47 22 96 32 58
>>> Development Section / IT Department Fax. + 47 22 69 63 55
>>> Norwegian Meteorological Institute http://www.met.no
>>> P.O. Box 43 Blindern 0313 Oslo NORWAY
>
--
Dr. Heiko Klein Tel. + 47 22 96 32 58
Development Section / IT Department Fax. + 47 22 69 63 55
Norwegian Meteorological Institute http://www.met.no
P.O. Box 43 Blindern 0313 Oslo NORWAY
Received on Tue May 15 2012 - 02:10:02 BST
