In principle a measurement could be humidified, although that seems unlikely.
How about _due_to_specified_humidity. That will indicate that someone needs to check on what the humidity is, and will cover all possibilities.
I would therefore suggest the following:
_due_to_ambient_aerosol [humidity information is optional, but recommended]
_due_to_dry_aerosol [humidity is low enough that there is negligible swelling, eg humidity < 20%]
_due_to_specified_humidity [humidity information is required]
Best wishes,
Philip
-----Original Message-----
From: cf-metadata-bounces at cgd.ucar.edu [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of John Graybeal
Sent: Monday, May 21, 2012 7:26 PM
To: Markus Fiebig
Cc: cf-metadata at cgd.ucar.edu
Subject: Re: [CF-metadata] new standard names for surface aerosol optical properties
I think the fundamental question is: Is the data in every measurement sense fully interoperable with data that is _due_to_ambient_aerosol? If not, why not?
In this case, it isn't fully interoperable because the values have been changed due to a process (partial drying) that's been applied, right? So wouldn't it be better to say "_due_to_drier_aerosol" or, less ambiguously, "_due_to_partially_dried_aerosol"? This explicitly points out the reason this is neither ambient nor dry. (I would have assumed the lack of any qualifier means we just don't know whether it's ambient or dry.)
John
On May 21, 2012, at 05:28, Markus Fiebig wrote:
> Dear all,
>
> a couple of weeks ago, I proposed a list of new CF variable names for surface aerosol optics properties (last version repeated at the end of this mail). We had a good discussion of the proposal, and due to lots of valuable comments, we managed to even out almost all issues, except for one, which left the proposal in an "almost accepted" state. I would therefore like to try to revive the discussion and bring it to a conclusion.
>
> The issue:
> CF aerosol variable names so far use the terms "_due_to_ambient_aerosol" and "due_to_dry_aerosol". For variables with "_due_to_ambient_aerosol", a co-ordinate variable relative_humidity is required since most aerosol properties are strongly dependent on particle humidification, and not taking this effect into account would render any model-observation comparison meaningless. The observations of surface aerosol optical properties I'm concerned with are intended to be on the dry aerosol. In some locations however (e.g. in the tropics), sample drying can be incomplete at times, leaving the sample in a state between ambient and dry. For this reason, I proposed a subset of variables with "_due_to_aerosol", also requiring a co-ordinate variable relative_humidity. In practice, these data would be used for comparisons in the same way as those with "_due_to_ambient_aerosol", where the humidity state needs to be taken into account, except that the humidity is neither ambient nor dry.
>
> I know that it has been CF policy to define "clean, textbook" definitions of standard names, and this is certainly desirable from a model point of view. On the other hand, measurements oftentimes just aren't textbook clean. Also, we need to continue to bring models and observations closer together, and such a variable would be a good way of achieving this without too much compromise.
>
> I'm curious to hear opinions, and hopefully come to a conclusion on this issue.
>
> Best regards,
> Markus
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Received on Mon May 21 2012 - 14:49:55 BST
