[Go-essp-tech] units of wetso4

[alison.pamment at stfc.ac.uk]

Dear Michael and Karl,

I am not in a position to change anything in the CMIP5 tables, however, I can do something about the CF standard name if it is incorrect. I would suggest creating a new standard name of
tendency_of_atmosphere_mass_content_of_sulfate_dry_aerosol_due_to_wet_deposition (i.e. removing the 'expressed_as_sulfur') with units of kg m-2 s-1. The definition could emphasise that the mass is expressed in terms of SO4. I think we need a new name rather than an alias for the existing one because this clearly isn't the same geophysical quantity as tendency_of_atmosphere_mass_content_of_sulfate_expressed_as_sulfur_dry_aerosol_due_to_wet_deposition. Would you like me to create the name? Can the aero table be amended or would that simply cause confusion at this late stage?

I noticed that the aero table also refers to a standard name of tendency_of_atmosphere_mass_content_of_sulfate_dry_aerosol_due_to_dry_deposition for the quantity dryso4. In fact this CF standard name does not exist (the 'expressed_as_sulfur' version does exist) so it looks as though we need a new name for this quantity also.

The standard name tendency_of_atmosphere_mass_content_of_sulfate_dry_aerosol_due_to_emission which is used in the aero table for emiso4 does already exist in CF. 

The aero table contains the question 'Is this "dry" or "ambient"?' next to the loadso4 quantity. Currently it is associated with the standard name atmosphere_mass_content_of_sulfate_dry_aerosol which does exist. There is also an existing standard name of atmosphere_mass_content_of_sulfate_ambient_aerosol if that would be a more appropriate choice.

Please let me know how you would like to proceed with the standard names. I leave it to the folks at PCMDI to make any necessary changes to the CMIP5 tables.

Best wishes,
Alison

------
Alison Pamment                          Tel: +44 1235 778065
NCAS/British Atmospheric Data Centre    Email: alison.pamment at stfc.ac.uk
STFC Rutherford Appleton Laboratory     
R25, 2.22
Harwell Oxford, Didcot, OX11 0QX, U.K.


From: Michael Schulz [mailto:michael.schulz at lsce.ipsl.fr] 
Sent: 15 June 2012 10:45
To: Karl Taylor
Cc: mark collier; go-essp-tech at ucar.edu; Jeffrey Stephen; Olivier Boucher; Pamment, Alison (STFC,RAL,RALSP)
Subject: Re: [Go-essp-tech] units of wetso4

Dear Karl and all,

that is indeed not what was intended and slipped through.

The unit should not be in "sulphur" but in "sulphate".  As indicated in the unit  kg m-2 s-1. I would expect the use of kgS m-2 s-1 if intended otherwise.

But now indeed it is written sulphur. I would think most people did not notice this standard name and data will be in sulphate unit. But this is not sure and might be a problem in interpretation of course. Probably nothing can be done about CMIP5. In Aerocom we try to check budgets "all-the-time" and then such factor 3 differences mostly surface.

regards
Michael 



Am 14 Jun 2012 um 19:09 schrieb Karl Taylor:


Dear Michael and all,

I have received an question (see below) from Mark wondering if there is a typo in the CMIP5 "aero" table.  Here is the entry:

1    Wet Deposition Rate of SO4    kg m-2 s-1            wetso4         tendency_of_atmosphere_mass_content_of_sulfate_expressed_as_sulfur_dry_aerosol_due_to_wet_deposition

I would note that the standard name above is an alias for 
tendency_of_atmosphere_mass_content_of_sulfate_dry_aerosol_expressed_as_sulfur_due_to_wet_deposition

Anyway, just wanted you to confirm I hadn't transcribed anything incorrectly. 

Even if there is some "inconsistency" in units between wetso4 and related variables, I think it is too late to change the CMIP5 specifications.  But we might want to rethink what we request the next time around.

best regards,
Karl



On 6/13/12 8:14 PM, mark collier wrote:
We just noticed that for the field wetso4 (Wet Deposition Rate of SO4) in table aero, the requested units say "tendency_of_atmosphere_mass_content_of_sulfate_expressed_as_sulfur_dry_aerosol_due_to_wet_deposition". We wonder if that was the intention, or if it is a typo, as every other variable was requested in units of species (SO4, SO2 or DMS), not sulfur. We overlooked that it says sulfur, so we provided data in units of sulfate, consistent with other related variables. 


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 	Dr. Michael Schulz                                               
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