Dear Charles
Thank you for these proposals. Following Jim's question and your answer, I
appreciate that you can't define a threshold value in a particular quantity
for your application of these masks. Perhaps another question to ask is whether
quantities with these standard names are supposed to be comparable across
different datasets. That is the main purpose of standard names, in fact. For
instance, cloud_binary_mask is quite a general-purpose-sounding name. You can
imagine that, if this were in the table with the definition you give it:
> cloud_binary_mask: X_binary_mask has 1 where condition X is met, 0
> elsewhere. 1 = cloud present, 0 = cloud absent (clear)
it might be used to label quantities with many different definitions of cloud
cloud presence/absence. The use of a common standard name would indicate these
quantities are the same, can be compared, and scientific conclusions can be
drawn from the comparison. But that might misleading. Is this acceptable?
If your intention is to define cloud presence/absence in a specific way, then
I feel it would be better to have a more specific standard name that identifies
the algorithm, on the analogy for instance of the existing standard name of
isccp_cloud_area_fraction. I think it is fine to have application-specific
standard names like that then they identify quantities which might be generated
by different providers and which should be labelled as comparable.
Best wishes
Jonathan
----- Forwarded message from Charles Paxson <cpaxson at aer.com> -----
> Date: Wed, 15 May 2013 15:34:02 -0400
> From: Charles Paxson <cpaxson at aer.com>
> To: CF-metadata at cgd.ucar.edu
> Subject: [CF-metadata] GOES-R generated binary mask products under proposal
> User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.28)
> Gecko/20120306 Thunderbird/3.1.20
>
> Dear CF Metadata Users Group,
>
> Through observations and analysis, GOES-R weather products produce
> binary masks for: aerosols, smoke, dust and clouds. No coordinate
> value is warranted (i.e. CF Metadata standard
> surface_snow_binary_mask) for any of these four proposed quantities,
> since a complex set of tests for each case, such as using brightness
> temperatures, are used to derive signatures of the four atmospheric
> constituents. The proposed masks are analogous and defined in a
> similar way as the CF Metadata standard names: land_binary_mask and
> sunlit_binary_mask.
>
> aerosol_binary_mask: X_binary_mask has 1 where condition X is met, 0
> elsewhere. 1 = aerosols present, 0 = aerosolsabsent
> smoke_binary_mask: X_binary_mask has 1 where condition X is met, 0
> elsewhere. 1 = smoke present, 0 = smoke absent
> dust_binary_mask: X_binary_mask has 1 where condition X is met, 0
> elsewhere. 1 = dust present, 0 = dust absent
> cloud_binary_mask: X_binary_mask has 1 where condition X is met, 0
> elsewhere. 1 = cloud present, 0 = cloud absent (clear)
>
> Please accept these four mask names for inclusion into the CF
> Metadata standard.
>
> Sincerely,
>
> Charles Paxson
>
>
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----- End forwarded message -----
Received on Sat May 18 2013 - 08:19:29 BST
